# Tunnel Hulll ?



## wyodeputy

Can anyone here elaborate on the benefits of a tunnel hull for a Outboard Jet. I've started a mod (16x48 w/ 35 HP jet). The hull is beat up pretty bad and I'm really having to work on it removing and covering dents. So this would be a good point to stop and fabricate a tunnel but I've never run a jet with a tunnel hull so can anybody mention the pros / cons? Don't wanna waste the time, effort and materials in fabrication if the difference is negligible. Thanks in advance !


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## crazymanme2

It gives your jet cleaner water.With a tunnel the water doesn't get pushed down in that area & the motor can be run higher on the transom.That is the differences that I noticed when I made a tunnel out of mine.


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## semojetman

I am also interested in making mine into a tunnel hull.

Would like to hear some before and after stories


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## optaylor823

I would say that if it does not cost to much money to add the tunnel then do it. It may save your jet foot one day. With the jet foot sitting higher than the bottom of the boat it helps to protect the foot and we all know a jet foot is not cheap. I run a tunnel on my boat and I think I can ran a little shallower then some of the boat that I had before with out a tunnel. The boats were not the same brand.


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## JMR

Sometimes, the difference between skimming cleanly over ledges and rock, or smashing the intake into a underwater wall of stone ...is inches. 
A tunnel gives you about 3 extra inches of clearance....which I have really wished I had before.


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## semojetman

I really like the tunnel idea, unfortuantely my boat is a flat bottom, and outboard jets do not recomend a tunnel on a flat bottom. I'm still looking into to it though.


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## Lil' Blue Rude

Tunnel hull + jet= cavitation! A jet intake can only be raised so much before it will begin to suck air. It's not the same thing as a prop. Even if the jet doesn't cavitate it will be hurting the performance of your boat because the nozzle off the jet will be 3 inches higher so it won't be pushing against as much water. it will be shooting alot more of the jet of water into the air. It will be the same as over triming your motor on a boat that won't bounce, once the jet gets trimmed so high you start losing speed because you don't have the opposing force from the water to push off of. . If there was something to a tunnel hull and outboard jets I think Blazer jet boat company would have had a tunnel hull model in production by now. That's just my 2 cents from years of outboard jet experience.


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## crazymanme2

A tunnel hull will let you run your motor a little higher than a normal flat bottom boat.The boat pushes the water down,that's why you have a wake.With a tunnel hull there is no bottom in the center to push the water down which lets you run your motor higher & in clean water.That's why some boat manufactures have a partial tunnel on the back of their boat.
A tunnel hull raises the jet foot above the bottom of the boat, protecting it from damage.

Here's a link to a tunnel boat:

https://www.akmining.com/boat/lor1655.htm


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## reedjj

Lil' Blue Rude said:


> Tunnel hull + jet= cavitation! A jet intake can only be raised so much before it will begin to suck air. It's not the same thing as a prop. Even if the jet doesn't cavitate it will be hurting the performance of your boat because the nozzle off the jet will be 3 inches higher so it won't be pushing against as much water. it will be shooting alot more of the jet of water into the air. It will be the same as over triming your motor on a boat that won't bounce, once the jet gets trimmed so high you start losing speed because you don't have the opposing force from the water to push off of. . If there was something to a tunnel hull and outboard jets I think Blazer jet boat company would have had a tunnel hull model in production by now. That's just my 2 cents from years of outboard jet experience.



So your saying that a jet motor and a tunnell hull don't mix? I thought that was the whole pt behind a tunnell hull. A lot of the manufacturers offer models in a Jet Tunnel... Lowe, G3, SeaArk, on and on.

Do you reccommend a regular flat bottom over a tunnell hull for a Jet outboard Application? I know lots of guys do it but I thought the tunnell with a jet was the best way to go for shallow running.


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## Lil' Blue Rude

When I said that none of the leading manufactures don't make a tunnel hull model I was talking about companies like Blazer, Legend, LegendCraft, Alweld, Weldbuilt. Here in SE Mo. Outboard jets are mostly what people are running and these are the main companies that tailor build boat for the outboard jet enthuisist. I've never considered Lowe, G3, SeaArk a leading manufacture for outboardjets because for ever jet you will see two with props. 99% of the boat that are made by the manufcturers I listed have jets on them.

If your raising the motor up 3 inches out of the water that would just mean that your are puttin 3 inches of your boat that wasn't tunnelled into the water so you boat hits instead of you motor. " A jet tunnel doesn’t work well with a flat bottom boat due to air ingestion." That is staight from the outboardjets site. It might work on a semi v brecause the jet foot would have to sit lower in the water then it would on a flat bottom boat. 

When I said leading manufatcure I should have also said that they are leaders in flat bottoms. If you want to run shallow get a light set up and make sure you've got the power to push it. The black lines in the pic show where a semi v bottom would be and the red line shows where the foot would need to be. If you have a flat bottom and you want to mod the bottom you can flatten out the center rib from the back to around 12" forward. Most manufactures have started to do this anyway. I do recomend a flat bottom over a tunnel hull for a jet. If you don't load your boat down way to much and keep it in atleast 3 inches of water you'll be ok for running skinny. They can run shallower but your probably gonna bump.


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## JMR

Based on where I've seen different hull types around the country, it seems that most of the non-tunnel jet outboard hulls (like Blazer Boats, which is located in Missouri) are in areas like Missouri and the mid-west where the shallow rivers don't have very much rock to deal with...and non-tunnel hulls run just fine.
And in areas like Virginia and Penn, the shallow rivers have a lot rock to deal with, and that's where the tunnel hulls (like James River Jets in VA, and RockProof Boats in PA) start showing up, because they are an advantage in those conditions.

You can get a Blazer hull that's as thin as .080, because it works just fine if rocks and ledges are not involved, and the lighter weight is more a performance advantage than the durability of a heavier hull gauge.
Going the other direction, you can get a hull from James River Jets with a .190 bottom, and if rocks are still a problem, have that bottom covered with UHMW. 

Just my opinion, ...I'm guessing mostly.


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## georgiaken

Up here in PA, it's a mixed bag and a matter of preference/budget. When buying used, you often have to compromise to what is available on the market and at what price.

Lots of guys run tunnels, but they also complain about cavitation.

The guys with tunnels and UHMW can usually get into slightly skinnier water than the guys with just a tunnel (no UHMW) or no tunnel at all.

By slightly, I mean an inch to three or so inches skinnier for the guys with tunnels. The UHMW gives you some confidence running areas that people without UHMW would avoid...it's slippery enough to slide over some areas when running fast, but it does add weight.

I am by no means an expert, but I have not seen the same enthusiasm up here for racing jets etc. It's more a means to get to fish than anything.

In the end, it's a matter of choice I suppose, but in PA, people seem to really go for the tunnel boats.

You'll see tunnels on many, if not most of the custom boats up here...you'll also see side fins, splash guards and sometimes jack plates as well.

Our rivers can be treacherous...


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## Lil' Blue Rude

JMR said:


> Based on where I've seen different hull types around the country, it seems that most of the non-tunnel jet outboard hulls (like Blazer Boats, which is located in Missouri) are in areas like Missouri and the mid-west where the shallow rivers don't have very much rock to deal with...and non-tunnel hulls run just fine.
> And in areas like Virginia and Penn, the shallow rivers have a lot rock to deal with, and that's where the tunnel hulls (like James River Jets in VA, and RockProof Boats in PA) start showing up, because they are an advantage in those conditions.
> 
> You can get a Blazer hull that's as thin as .080, because it works just fine if rocks and ledges are not involved, and the lighter weight is more a performance advantage than the durability of a heavier hull gauge.
> Going the other direction, you can get a hull from James River Jets with a .190 bottom, and if rocks are still a problem, have that bottom covered with UHMW.
> 
> Just my opinion, ...I'm guessing mostly.


 :mrgreen: I don't know what part of Missouri you where in but we got plenty of rocks and gravel. :mrgreen: You just have to watch what your doin and be quick enoughto get out of trouble.(or have good insurance) My biggest thing is if there was something to a flat bottomm tunnel, Blazer would be making or have made something considering they where dezined around outboard jets.


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## semojetman

I have checked with Outboard Jets Co. and they agree with the fact that tunnels are not good on flat bottoms. I see the advantage and the disadvantage on a semi-V.

From what I've seen, read, and heard, I believe for me, i'm just gonna run my flat bottom and be happy.

I've ran a flat bottom 1752 thru 3 inches, so I dont have any business in anything skinnier than that anyways


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## Scottinva

On the East Coast, where we are not just dealing with gravel and rocks, but razor sharp ledges, pretty much all of the custom builders put tunnels on their boats - Snyder, JRJ, Rockproof, etc. If they are properly setup, they are a non issue for cavitation. Most are also going from building flat bottom boats to a slight semi V. I have a custom Snyder with a tunnel and 6" hydraulic jackplate - a big no no. I have cavitated 4 times in 3 years (over 40 trips a year) and every time was running through 1-2 footers. I am very happy with my setup and wouldn't trade it for anything.

Scott


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## Lil' Blue Rude

1-2 footers?? We don't have ledges but we to have some bad showels with rocks as big around as a 55 gallon drum. They'll split a boat wide open.


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## Scottinva

I think the big difference is our boats are built to run into big boulders and take the impact. They are not speed demons by any stretch of the imagination - mid to upper 30s max! and any loss in speed due to the tunnel is not an issue. Our boats have 3/16 to 1/4 in bottoms with 3/8 to 3/4 UHMW screwed to the bottom of that. I have hit boulders running 30 mph so hard that the we went completely airborn. The only damage to the boat was a small gouge in the UHMW. Just a different type of boat for a different area. Out here we run tunnels. There may be a loss of speed, but I would rather have the protection the tunnel provides. Just something different. I love the big boats with the 250 outboard jets, but they really aren't that practical around here unless it is built like aa absolute tank.

Scott


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## reedjj

Its very interesting... All the different points of view from members from different parts of the country. 

I was gonna do a jet on my boat but all the Fl guys I talked to said DO NOT do it. Apparently here in Fl the impellers suck up so much sand that they wear aout so fast the benefit of a Jet outboard does not outweigh the cost. I was told if I wanna run really shallow swampy land to get a mud motor.


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## Lil' Blue Rude

Is it really that bad of a river that you can't dodge the rocks? Please don't think I'm meaning that as a smart blank comment I'm just curious why you guys need such beefy boats. We don't run big 250hp motors where I run. I personaly own a 40/28 Evinrude and love it. I run the Current River here in SE Mo and there are alot of places that are 3 inches deep and around 30 feet wide. What are boats lack in durabilty the more then make up for in speed and manuverability. I can go from about 40mph down river to a dead stop pointing back up river with the crack of the throttle.(Scare the crap out of you too :shock: ) Did once, don't want to do it again unless I have to.


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## Seth

Lil' Blue Rude said:


> Is it really that bad of a river that you can't dodge the rocks? Please don't think I'm meaning that as a smart blank comment I'm just curious why you guys need such beefy boats. We don't run big 250hp motors where I run. I personaly own a 40/28 Evinrude and love it. I run the Current River here in SE Mo and there are alot of places that are 3 inches deep and around 30 feet wide. What are boats lack in durabilty the more then make up for in speed and manuverability. I can go from about 40mph down river to a dead stop pointing back up river with the crack of the throttle.(Scare the crap out of you too :shock: ) Did once, don't want to do it again unless I have to.



180's in a flat bottom are fun. It's good for scaring and soaking your passengers too. :lol:


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## georgiaken

Lil' Blue Rude said:


> Is it really that bad of a river that you can't dodge the rocks? Please don't think I'm meaning that as a smart blank comment I'm just curious why you guys need such beefy boats. We don't run big 250hp motors where I run. I personaly own a 40/28 Evinrude and love it. I run the Current River here in SE Mo and there are alot of places that are 3 inches deep and around 30 feet wide. What are boats lack in durabilty the more then make up for in speed and manuverability. I can go from about 40mph down river to a dead stop pointing back up river with the crack of the throttle.(Scare the crap out of you too :shock: ) Did once, don't want to do it again unless I have to.



Yes, it really is that bad.

They refer to sections of the river as the "X rock garden" or the "Y rock garden." We literally have rock gardens and ledges and boulders and the changes in the terrain can happen almost instantly.

We have rocks that jut up under what appear to be clear chutes...the list goes on and on...of course, I am referring to the Susquehanna River.

So, to use your point of view in reverse...if it wasn't needed, boat builders in our area wouldn't bother to add tunnels and UHMW plastic, just like in your area, if it was needed, Blazer would have done it already.

I can't think of too many guys who would voluntarily pay more money to be heavier and go slower unless it was needed. When guys talk about taking thin bottom aluminum hulls out on the river with jets, people always caution them...there are countless stories of guys opening up like sardine cans...

Some of the guys I know joke about the "aluminum that lines the river." Sometimes, you can look down while going up the river and see the glints of aluminum where people have hit over the years 

Again, I am no expert, but the rivers up here run wide and often fast in some area (Class II and III rapids) and are full of rocks...I guess the wide variety of terrains is what makes it such a great smallmouth fishery...


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## Lil' Blue Rude

Ok I'm curios now, do any of you guys have some pictures of this river.


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## optaylor823

Ok I will throw my 2 cents in. I fish the Duck River in TN and the river is not that bad, but it does have its bad spots. After having 2 jet boats. One a 15 flat bottom with a 25/20 jet and the other a Triton 176 Sport with a 90/65. I now own a Snyder with a tunnel and UHMW on the bottom. I put a hole in the Triton, because the motor was not big enough to let me run any other way but wide open, and we all know that is not good in a jet when you try to turn. The other reason was the boat was not balanced good and was rear heavy. So now I have a heavy slow boat, but I do not have to worry about hitting rocks. I do have a tunnel in my boat and believe I can run a little shallower with it. I do agree that a tunnel is not for every boat, but in my boat I believe it works great. I do agree that certain boats are better in different rivers. The UHMW is great because I do not have to worry about that dreaded noise of aluminum against the rocks. I guess one thing I am trying to say is that some people may have the extra protection and not need it, but it does ease their mind.

This picture was posted at one time over at RiverSmallies and I think it come from some one trying to show part of the Susquehanna river.


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## bajacoop

I think we are talkign about 2 completly different kinds of rivers. Here is MO we are running skinny water mixed with rocks and such. Where they are running is more like a white water rafting type river. Is that correct?

We have lots of areas where you have to run real skinny because there just is not any water. I think they are in a situation where the depth of the river is much greater but there are a lot of rocks sticking up all over the place.


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## RPjet

The Susquehanna is a huge river. In some places it is nearly one mile wide but very shallow. It is not the rocks you have to worry about....it is the ledges! They are immoveable objects. Pictured above is probably the most notorious stretch on the Susquehanna for destroying boats, called the "Ft. Hunter" area. This area regularly eats boats, intakes and propellers with regularity. You do not want to run this area with a boat of less than .125. The only boats that survive in this area are built of .190 or better and also have UHMW of between 3/8 and 3/4 bolted onto the bottoms of the hull. Thus the reason that tunnel hulls rule on this river.

The whole river between Sunbury and Columbia is owned by shallow running jet boats. Boat owners are lumped into two categories on this stretch.....those that have tunnels and those that wished that they had tunnels. This area is so tough on jet foots that it has spawned two companies to offer jet foots made of UHMW.....Rockproof boats and Top Notch CNC. Both offer a quality option for those that do not have tunnels. I give the nod to Rockproof for those that do not have a tunneled boat and the Top Notch to those that do.

Me?........I run a RiverPro inboard so I don't have to deal with any of this!


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## georgiaken

You beat me to it re: Ft. Hunter. It's a great place to fish if you're down river of that rock garden in the pool...if you want to go up river, through that rock garden, you'd better have a thick hull and/or UHMW on your hull.

My boat doesn't have a tunnel and is only .1 I think...at any rate, I would not run that stretch of the river through the rock garden...no way.

Guys like me (without a tunnel or UHMW) have to get out, trailer and re-launch.

The worst part...depending on the time of year, some of the ledges are spectular in terms of the fishing.

I haven't been fishing long, nor have I been running the Susky for any extended period of time, but I know better than to get out there and sink my rig...






Edited: This video shows what some of the rocks look like in the shallows down near the mouth of the river...

https://www.youtube.com/watch?v=8fXk1LFK8OY
(it's not my video, but it does show what it looks like...and no, folks don't run through that)

End edit...

The whole river doesn't look like this, but there are definitely areas like this. There are also areas where the river is only 2 feet deep or so, with small pools that are 5-8 feet deep and rocks everywhere.

It's not advisable, but you could walk across the river at some points and only have to be worried about being "underwater" for 25 yards or so, and then, just barely....but the river would still be a mile wide.

Oh yeah...RiverPros rock! That's like a dream boat...for me anyway.


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## S&amp;MFISH

Do you guys know the story behind RiverPro boats? They are built about 35miles south of St.Louis in Hillsboro,Mo. By a man who could not find what he wanted in a "river boat" manufactured by the usual suspects. So he designed at started building his own line the way he thought they should be built. He started in his garage behind his house,and then moved the operation into town a few years ago.I live about 15min fron his shop. At the time I bought my Alumacraft MV1756RiverRunner, I was looking hard at them,but couldn't afford one so I got the RiverRunner for about 14k less. They test run them on the Big River,which I fish regularly.Very small river,some places only 20-30ft wide and 3-6in deep, mostly about 50-100 ft wide and 2-7ft deep.

Oh,by the way the RiverRunner is an Mod V Jon with a 2'' tunnel.It has a 115/80 Merc Jet on it. And I couldn't be happier with it.I could only be happier if I had a RiverPro in the garage next to it.


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## reedjj

hahahaha! That looks crazy! Gravel bottoms and logs look like childs play compared to that place!

And to think I DID NOT get a jet because I was worried about a little sand getting sucked into it.


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## reedjj

Any pics of the UHMW? What is it? Like a hard plastic coating for your hull? Carbon fiber shield material?


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## optaylor823

UHMW is ultra-high-molecular-weight. I compare it to a teflon cutting board. I do not have any good pics of it on the bottom of a boat, but here it is on the side and it is put on the same way on the bottom. On my boat it covers the whole bottom of the boat.


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## turne032

https://www.youtube.com/watch?v=Q8lnpPG9Hs4&feature=related

this is our little stretch of Current River~


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## turne032

https://www.youtube.com/watch?v=yU_tltc2v7U


and another one


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## georgiaken

turne032 said:


> https://www.youtube.com/watch?v=yU_tltc2v7U
> 
> and another one



So, this is kind of funny for me...when I was dreaming of getting a jet in late fall/early winter, I started watching youtube videos of jet boats. I was wondering what size jet to put on my old boat (14ft Roughneck). I did the math and for the cost of the jet, I could upgrade and sell my old boat.

But, the point is: I watched this video on more than one occasion. I was always taken aback by the guy who commented about you being an "outsider" to Van Buren. As a matter of fact, that comment is what let's me know this is the video I watched...it kind of stood out as a little "off."

Here's a video of a guy hitting on the Susky...he went up a ledge and I guess he judged it wrong. He has a tunnel and still split his rig...

https://www.youtube.com/watch?v=ENDLTH-DTmg

I don't know the guy or anything, I just found this on youtube a few days ago when looking for videos to show on here...


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## turne032

wow!!! we have a couple places that have big granite rocks like that. but i cant get over how wide that river is. that amazes me. I would never take my boat through that. 


that second video is not me. but i do know him, a very nice guy. this area of missouri is very territorial. locals think they own it, outsiders think their entitled to, government tries to take a little more of it every day. 

i just enjoy being their. ive never been to a place so beautiful as the current river. big bluffs, clean gravel bars, cold clear water, eagles soaring....its really awesome. and...i enjoy jet boats.


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## semojetman

The current River is beautiful. And like you said, the locals think they own it.

Well, to a point I think they deserve a little recognition for being there through everything but it a great river that should be enjoyed by all that love that sort of thing.

They complain about "tourist", but they should just be happy that they have something nice enough that people want to come see it.

I am not a river local, but not a far away visiting tourist.
I was born and raised in Poplar Bluff MO but own property near river in Ripley County.
Grew up with friends in Grandin,Hunter, Ellsinore, Doniphan, and other towns close to the river.


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## georgiaken

There are definitely some wide open places on the river as well, with less ledges, boulders and rocks, but yeah, it tends to be pretty wide.

The river has a few impoundments between dams where people can run props, but even there, they ave to know the place or they might hit.

When you learn different areas, you can run them without a lot of issues.

We use river gauge height to determine when the best times are to go out...strictly in terms of the river (we use the weather to, for fishing)...


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## Scottinva

I have been away for a while and just have a few comments. Yes the Susky is that bad. I fish there and the James River and New River in VA. The James gets so low in the summer that you literally have to drive over rocks to get to water. Thus the need for the heavy duty boat. Another comment - it was stated that you would lose performance with a tunnel because the motor was higher. I think this is a little flawed. I have a 6" hydraulic jackplate on my boat and I run the fastest when it it all the way up and pretty much of he jet is out of the water. If I lower it an inch I lose performance. For the record, I run a 16x60 Snyder Mod V with tunnel and with a 115 Etec. UHMW bottom and UHMW intake with a 6" hydraulic jackplate. Optaylor do you have a Jackplate on your Snyder?? Any comments on that?

Scott


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## semojetman

After seeing what these guys over in VA and over there are running, I have to admit, we do not have rocks, We run our boats through pillows and mattresses compared to some of the stuff I've seen from over there.


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## Lil' Blue Rude

I wasn't sayin it doesn't help to trim your motor up it hurts performance to raise the motor up too much. I can get my boat to lay down flat when I'm running wide open down river off a shoal and it won't bounce if I keep triming it gets to the point it starts to slow down because the jet is raised to high, it doesn't cavitate or any thing like that you just feel it lose speed and I can look at the gps and it will have lost a mph.
Yeah you guys have it ruff there for sure, If someone knew what they were doing and had the guts to could they make it through a place like that without spliting a normal boat open? Don't think I would want to take my boat through that, maybe a junker that could pick up cheap, but not mine. It would be wild ride and make for a real good youtube video. :mrgreen:


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## optaylor823

I do have a jack plate on my Snyder. I also agree that if I drop the motor I lose some performance. The only time I ever drop the jack plate down is if the water gets a little choppy and the motor goes to sucking air. I can still trim the motor up a little with the jack plate all the way up, but I only do that when I am running real shallow water, because it also seem to make the performance drop. Like I said earlier tunnels are great on some boats, but not meant for all. I feel the same way about jack plates.


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## Scottinva

One more advantage to a tunnel - if you damage the area right in front of the intake on a flat bottom boat, you may not even be able to get on plane. By having a tunnel, the area in front of the intake is protected and isn't prone to damage. My dad had an Xpress and it a ledge and put a dent about 1.5" deep right in front of the intake. He went from beng able to run about 25 mph to not being able to get on plane at all due to this damage. He ended up putting a tunnel in and never had any more problems. He still hit a rocksand ledges, but the damage never affected performance because the tunnel is somewhat protected. Just another + for a tunnel.

Scott


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## reedjj

Scottinva said:


> I have been away for a while and just have a few comments. Yes the Susky is that bad. I fish there and the James River and New River in VA. The James gets so low in the summer that you literally have to drive over rocks to get to water. Thus the need for the heavy duty boat. Another comment - it was stated that you would lose performance with a tunnel because the motor was higher. I think this is a little flawed. I have a 6" hydraulic jackplate on my boat and I run the fastest when it it all the way up and pretty much of he jet is out of the water. If I lower it an inch I lose performance. For the record, I run a 16x60 Snyder Mod V with tunnel and with a 115 Etec. UHMW bottom and UHMW intake with a 6" hydraulic jackplate. Optaylor do you have a Jackplate on your Snyder?? Any comments on that?
> 
> Scott



you got any pics of your rig? Sounds awesome!


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## Scottinva

Here is a pic. 

Scott


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## gotasquirt

nice looking ride what are the specs on the hull length with hull thickness huow much v thanks will


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## semojetman

odd looking boat.

But it looks like its all about function.

Looks like a strudy built boat too.


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## georgiaken

Snyder boats are like tanks.

Even the Pennsylvania Fish Commission ran one of their boats on the Susky at some point (don't know if they still do or not).

They are the hardcore boats that Susky fisherman dream of having...bottom line, they get the job done.

I went on a guided trip in one of those...an 18 footer...that boat flat out does what it was built to do.


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## reedjj

Wow! That is a nice boat!


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## Scottinva

It is 16' long with a 60" wide bottom. 3/16" thick aluminum + 3/8" UHMW screwed on the bottom.


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## georgiaken

Really nice boat...

I wish my ranger had a thicker skin


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## optaylor823

Nice looking boat Scott. Mine looks very similar just is 6" wider.


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## riverracer

I have read some of these posts and it is a catch-22, ok u put a tunnel on ur outboard jet to set ur motor up so u wont damage ur shoe, by putting a tunnel in ur boat u will loose a little of floatation so therefore ur boat is setting deeper in the water. :?:


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## Scottinva

WIth the tunnel, you aren't going to be any noticble distance deeper either on plane or while drifitng I guess in theory you would have a little less surface area, but you are raising your intake up way more than the amount you would lose. I would much rather my boat hit than my motor. If you fish any area that will damage intakes, imo the tunnel is well worth it. If your area isn't that treacherous, you may not need one.


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## optaylor823

I never thought about it before, but I guess you do lose a little bit of surface area when you put a tunnel on a boat. I also have to agree that the pros out way the cons if you are running where something may tear the jet foot off. Think about the cost of the tunnel compared to replacing a jet foot or two. Not to mention the time you would lose off the water.


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## turne032

coppied from jetdoctor.net

Shoe for large jet-when ordering please specify: 
6 5/8" part # 141.1
6 7/8" part # 141.2
7 3/16" part # 141.3
7 3/8" part # 141.4 $370.00 
Large Intake Assembly (Shoe) - $365.00 


i would say it is cheaper for me to replace a shoe on my motor than trying to repair the bottom of my boat!


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## semojetman

Well we have heard pretty good argument from both sides. Sounds like it is all personal preference. The pros outway the cons for some and the cons outway the pros for others. Just depends what your going for.


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## Scottinva

Again, it is personal preference. For my boat, I am not worried about damaging the hull. That is why I have the 3/16 bottom and UHMW on top of that. I would have to do something real stupid to damage the hull to the point that it would need repaired. So for me, the intake is the weak link and the most expensive repair item and I want it protected - hence the tunnel.

Scott


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## Lil' Blue Rude

I see how the tunnel hulls work with a jet but I still think the boat would set down in the water a little farther. When I was thinking of tunnel hulls I've been thinking of light wieght hydros where there going fast enough to pick the tunnel up out of the water. Now that I think about it a heavy boat would be funneling the water up to the jet because it's to heavy to have lift like a small hydro.
How shallow will your guys boats run without hitting the bottom of the boat? I know I've run 2 inches before and I hit with my shoe but the boat never touched. ( I have to thank the canoes for putting be in that position :evil: )


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## Scottinva

The length of the tunnel is only about 2 ft long and maybe 1 ft wide. So the total surface area reduction is only about 2 sq ft. Not sure how shallow I can run but I would estimate 4-5 inches depending on bottom structure and possibly shallower over short sections.

Scott


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## reedjj

Up untill I learned about Blazers, Legend, SJX, and all these custom boats I've seen on here, I thought this G3 was the ultimate boat. "my dream boat".

The pic's illustrate what a Tunnel means to some us. I say this because I think depending on where your from a "Tunnell Hull" may mean somethinng entirely different to one person than it does to another.

I think most of us east coast guys think of a Jet Tunnell as this.


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## reedjj

Prop Tunnel


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## Lil' Blue Rude

I was thinking for some reason that the tunel ran the lenght of the boat. It doesn't look like the G3 pictured has it's motor raised any higher then the motor on my boat. Could be how the picture is. How much higher is that motor raised?


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## S&amp;MFISH

Hey Rude,on my Alumacraft with a 2'' tunnel,the shoe sits 2'' higher than it would without a tunnel.It would still get wacked if I ran over a rock.Because it has before,on the Big. The tunnel starts about 3-4ft from the transom. I believe it would take a 4-6'' tunnel to protect your shoe.


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## reedjj

S&MFish,

Do you have the 1546 DDT?


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## S&amp;MFISH

No reed. It's an '06 MV1756RR with a 115/80 Merc jet.


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## reedjj

S&MFISH said:


> No reed. It's an '06 MV1756RR with a 115/80 Merc jet.



Is there a thread with pics? Sounds nice!


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## S&amp;MFISH

Here you go reed.These are from '08-09. Scroll down about halfway down the page.
The first 2 are at Lake of the Ozarks and the last 2 are from CouncilBluff.
We bought it new in spring of '07.I'm going to get some recent pics after I do a good cleaning when the weather clears up around here.I'm about halfway thru it now,just needs the wash job.

https://www.tinboats.net/forum/viewtopic.php?f=48&t=7593


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## reedjj

Im so jealous of the jet motors.


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## sparkbr

A boat with a tunnel will sit lower in the water, but it is minimal. In order for something to float, it must displace it's weight in water. Assume something around a 16' boat weighing 1000 lb loaded evenly (for simplicity) and lets say it's footprint in the water is 13' x 4'. So 1000 lbs divided by 8.34lbs per gallon of water is 119.9 gallons it must displace to float. 119.9 times 231 cubic inches per gallon is 27696.9 cubic inches... 27696.9 divided by 7488 (the foot print of the boat) equals 3.69" submersed.

For a 2" tunnel 4 feet long and 10" wide, that reduces 480 square inches, or 2.07 gallons. The same as adding 17.32 lbs in the rear of your boat. If we were to refigure the above for a boat weighing 1017.32, it comes out to 3.76" submersed. So that 2" tunnel makes the boat a 1000 lb boat sit .07" lower in the water, or a little over 1/16"

Now, lets say we go extreme and take the area of the tunnel completely out of the picture (which could not happen unless the tunnel had no 'ceiling' to it) say the tunnel is 10" wide by 4 feet long again - Now the foot print of the boat becomes 7008" instead of 7488. The boat would now be submersed 3.95"


Now granted all of this is assuming the boat is loaded evenly in the water, so all of the numbers here are just for comparison, but all in all, the tunnel has a minimal effect on how low the boat sits in the water


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## Lil' Blue Rude

This post has gotten way to in depth. :lol: When I said sets lower in the water I meant rides lower in the water. peolpe with the tunnel hulls are claming they can run shallower water then they could if they had a flat bottoms. I think the oppisite is true. Your jet might run shallower put your boat won't. Here's a pic of a 17' 52" blazer sport with 4 people in the back half of the boat and it isn't running as deep in the water as the G3 posted earlier.


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## reedjj

I was just looking on the Sea Ark Website at tunel hulls and Jet tunnel hulls. There is a difference between the two different types of Tunnel huls in thier boats. 

The Prop tunnel hull is described as....

Copied from Sea Ark Website: https://www.seaarkboats.com/boat.php?measure=Standard&boat=1652MVT

"SeaArk’s Tunnel Hulls are designed to be used with a conventional prop driven engine. The transom is higher than on a conventional hull and a “tunnel” is designed into the bottom of the boat which allows the engine to be raised so the prop turns inside the “tunnel.” Tunnel Hulls are most often used when the operator needs to run in very shallow water but does not want to lose the “bite” of the prop. Standard features and options are similar to Non-Tunnel Hull models".

And the Jet Tunnel hull is described as: 

Copied from Sea Ark Website: https://www.seaarkboats.com/boat.php?measure=Standard&boat=1652MVJT

"SeaArk’s Jet Tunnel Hulls are designed to be used with a jet driven outboard. The Jet Tunnel design includes a flat roof in the tunnel to direct water back to the intake of the jet. The thrust of a jet outboard is about 70% of an equal sized engine with a prop. This fact and the fact that a jet uses water for propulsion instead of a metal prop, means that the operator loses some speed, directional control, and performance. What is gained with a jet is the ability to operate in extreme shallow water conditions without the fear of ruining a prop. Most of our customers using Jet Tunnel boats use them in shallow rivers where they need to pass through extreme shallow spots. Standard features and options are similar to Non-Jet Tunnel Hull models, however, they are offered in center console only".

I would only guess that a jet outboard would not work AS WELL on a tunnel hull meant for a prop, and the other way around due to the specific designs. 

When I was looking at buying the G3 I noticed that the Jet Tunnel was very shallow, just enough to give the shoe some clearance (you can see this in the pic above). And the Prop tunnel was much more pronounced to make room for almost the entire prop. Only the skeg was below the hull of the boat.

I think the engineering, design, and science behind boat hulls, even something as simple as a "Tin-Boat" is very interesting. I am really enjoying this thread. Especially learning about the different pts of view, applications, hull designs and materials used on everyones boats from all over the country (and Canada). The guys in MO are running different setups than the guys in Ak, and the guys in PA are running heavy duty with UHMW. Some are running jets in FL and yet others swear up and down that its a bad idea. Inboard Jets running class 5 rapids in Idaho, and guys in Alabama running jets on riveted jon boats.

I am learning a lot from everyone on here and will put it to good use on my next boat.


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## optaylor823

LiL Blue Rude peaople maybe claiming they can run shallower, but we all know the only true way to find out is if we take a boat with out a tunnel and add one. Maybe this is a case for Mythbusters. 
Reedjj. A tunnel hull for a prop does not work good for a jet outboard. They are to big. Also if any one is interested here is some good reading on jet tunnels, and other information about setting up a jet boat.


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## fender66

optaylor823 said:


> LiL Blue Rude peaople maybe claiming they can run shallower, but we all know the only true way to find out is if we take a boat with out a tunnel and add one. Maybe this is a case for Mythbusters.
> Reedjj. A tunnel hull for a prop does not work good for a jet outboard. They are to big. Also if any one is interested here is some good reading on jet tunnels, and other information about setting up a jet boat.



Um....optaylor.....think you forgot to add a link to that reading you mentioned.


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## Lil' Blue Rude

Lets see a tunnel do this :mrgreen: . https://www.youtube.com/watch?v=V9iXL-omjkA&feature=related


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## optaylor823

Yes I did sorry about that. https://www.snyderboats.com/faq.htm


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## RPjet

Lil Blue,

Believe it or not but a tunneled jet will go the same place that the boat you posted the video for with one exception. If you watch closely the motor actually hit and kicked up upon contact with the bottom. A tunneled hull boat may or may not hit under the same circumstances but I believe that the motor would not have made contact as much.

You seem to be misinformed or under the wrong impression about tunneled hulls. They will run as shallow as a non-tunneled hull. Most east coast tunnels are only about two inches high, about one foot wide and two feet long. They do not stretch the length of the boat. 

And another thing - east coast boats are made much heavier and thicker than those you keep posting pictures of. A hull of less than .125 will not survive very long on the east coast rivers. Sure lighter boats will run shallow but will not take a hit and survive like those that we run in our rivers.

BTW.......I run a boat from Missouri......a RiverPro LoPro! So someone out there knows what it takes to run the east coast rivers (Thank you Kevin Turner!).


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## Lil' Blue Rude

I meant that as more of a joke, like look how shallow this thing runs. :shock: I know the motor hit. But still pretty cool that he ran that shallow.
Like I said in an earlier post I see how your tunnels work. I was thinking of the tunnels like the ones on a small hydro plane where the tunnel runs the length of the boat.


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## Scottinva

It really all just comes down to what you want and where you run it. None of our jets could handle the big waters in the Northwest. They have totally different waters. Our boats on the East coast are made for the Susquehanna, James, and New Rivers. No offense inteded, but one of those thin hulled boats would not last very long on the Susky at summer lows running as fast as those boats run. That is why our boats are built the way they are. They still run real shallow and can take a beating. If you look at the Snyder website, you will see how heavy duty they are made. They may not run as shallow as a Blazer Sport, but it is not because of the tunnel, it is because they probably weigh 2x as much or more. However, if we hit a ledge running 30 mph, we will live to see another day with maybe a small dent in the UHMW. A thinner hull with no UHMW will not be so lucky. Just different boats for different waters. You don't need those heavy duty boats like we need. Ours may be slightly overkill, but I like the insurance.

Scott


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## Lil' Blue Rude

I know your guys boats are alot tougher then what we run. I'm glad we don't need boats to be that heavy duty around here. Kinda cool to get all of the diffrent points of veiws from diffrent people on diffrent boats.


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## sparkbr

Here is a pic of the tunnel I welded into my 1652 roughneck. I run a 60hp prop driven mariner on a hydraulic jackplate and can run on plane in about 3-4" of water and at low speeds in about 5-6" depending on how loaded I am. There is alot of mud bottomed water around here though so making a mistake is rarely costly.


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## shallowminedid

my buddy has a beaver tail that was rebuilt into a tunnel hull by snyders.. had the uhmw bottom added.. it now leaks like a civ? and is almost twice as heavy but it will drive onto land and not hurt anything he can park it up out of the water on the shapest nastiest rocks and not worry about his foot.. if u get the tunnel add the splash sheilds and cav plate if needed and u should be fine.. my boat is not a tunnel and i can not get to some of the places he can


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