# flat bottom vs modified v



## goose (Apr 13, 2014)

Fairly new to jet boating and looking into having a boat built. What are the advantages/disadvantages of flat bottom vs a modified v hull.


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## LarryMc (Apr 13, 2014)

Can't completely answer your question since I have never owned a flat bottom jet. I have ridden and fished in them though and can make a few observations. The flat bottom rides a lot rougher in choppy water than a modified V. Also, the flat bottom will slide more in turns than a Mod V. On the positive side, all things being equal, a flat bottom will run a bit shallower than a mod V. 

One thing to be sure to check out when choosing a boat. Make sure that it doesn't have a big center keel. I used to have a 1750 Duracraft Mod V with a Merc 60/40 jet (same one now on my Lowe 1655CC). The Duracraft had a big center keel with a drain plug in it and it gave me trouble with cavitation as long as I had it. I finally gave up on it, bought the Lowe and put my motor on it. The Lowe has a small keel, but it has never given me trouble with cavitation under normal conditions . 

You might want to take a look at the Outboard Jets boat selection site at the link below, some good advice on choosing a boat for a jet.

https://www.outboardjets.com/boat-selection/

You didn't ask about this, but I would like to add that you should strongly consider either a center console or a stick steering setup for your boat. The increased visibility of either over a side console or tiller steer is tremendous. I've had all of them except a tiller steer and of the three I've used I much prefer the stick steer, but they are a bit harder to come by.


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## smackdaddy53 (Apr 13, 2014)

Outboard Jets recommends at least 6 degrees deadrise at the transom meaning flat bottoms are not ideal for jets BUT a local dealer has been running flat bottoms with tunnels for years, he actually has Alweld build a tunnel he designed into their boats from the shop and he has no problems.


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## TwoEyedJack (Apr 13, 2014)

I was out in the boat in my signature yesterday. We put in on the Snake River above Swan Falls dam and ran upstream (east) about 10 miles and back. There was a sustained 35 MPH wind west to east aligned with the river and opposing the current. Down wind was not too bad, but coming back was nasty with white caps. This is the first time I have had this boat in rough water. The bottom has a very shallow V. At first I was hitting the waves like I would with a V-hull and it slammed pretty good a few times. Then I slowed way down and was pleasantly surprised at how slow I could go and still maintain a plane. In fact, there is such a subtle change from planing to non-planing that you hardly notice it. So we went slow on the way back and I tried to hug the bank with the smallest waves. 

The V-hull boats I have run in the past have been very sensitive to weight distribution. This boat is far less sensitive. 

For running rivers with shallow spots, my boat is perfect. If I were running exclusively in lakes, I would get a deeper V to deal with the rough water better at speed.


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## goose (Apr 13, 2014)

Thank you for your responses. I am going to have a Alweld boat built but not sure how i want it speced out. I know i want a 16-17ft boat with a 60/40 jet.


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## smackdaddy53 (Apr 14, 2014)

You should call the owner of Sonny's Marine in Port O'Connor Texas and ask about the boats he has made for his shop. He sells a lot of rigged out 16 foot outboard jet boats with 60/40 Yamahas.

the outboard jet rigs


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## dhoganjr (Apr 14, 2014)

It should depend mostly on how you want to use it. Most jet boats around here are flat bottom and are run mostly on rivers and occasionally on the lakes. I have never seen a tunnel hull flat bottom jet around here, may be a few, but not common.

If you plan on running mostly lakes and bigger rivers a mod-v might be a better choice. With that being said I have never been in a mod-v, only flat bottoms.

When I ordered mine in '02, my main plan was for gigging. A flat bottom is more stable, runs shallower and is very suitable for jet use. 3 people can stand across the front deck and I can stand on any corner of the boat with little movement. Though my boat is also wider than most, with a 60" bottom and 85" across the beam with 28" sides. Yes they do slide in the turns which takes some getting use to and are rougher riding in heavy chop and waves. After 12 years of use, I would build it the same way today. I run rivers and creeks the most, from ankle deep water to water not much wider than the boat. I also use it on smaller lakes around here and Lake of The Ozarks several times a year (mostly at night and in the upper part of the lake). 

Just my .02 worth, Good luck and enjoy whatever choice you make. If at all possible see if you can get anyone to take you for a ride, should help with your choice.

Give www.trouttandsons.com/ in St. James, Mo a call, they will be able to answer any questions you have.


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## pramnut (Apr 15, 2014)

Even a shallow v (4-7 degrees) will make a huge difference in the way the boat turns. Flatbottoms (especially wide ones) are real slippery and can be hard for seasoned v boat folks to get used to.
When I run my friend's 15X54 Wooldridge with hardly any deadrise, I get thrown off balance because I habitualy set up my stance to slide into a hard turn, which is does very little compared to my 16X60 flatbottom. Turn timing, angle, and recovery is a lot different with even a little v all the way back to the transom. A flatbottom can also come out from under you real quick like overcorrecting on ice in a car.

Flatbottoms are more stable and less expensive to build.

Ride is slightly better with a shallow v (more of a sound difference really). Much better with a mod or or deep v.

Cavitation can be an issue in riffles, chop, and rapids with a flatbottom because air gets pushed underneath and straight back into the intake. Air goes more off to the sides with a v for a cleaner prime.

V hulls "push" a little more water and are slightly less efficient and slower than a flatbottom with comparable power. Many builders agree on this but we are talking about jetboats here.

Flatbottoms draw less water on step, but an inch or two at most? The chine won't dip as much on a turn in shallow water, but you can't push a cushion of water up a riffle as well as with a v.

V's have become much more popular in recent years and few custom builders offer straight sleds anymore.


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## semojetman (Apr 15, 2014)

If your looking at jets, you obviously want to run shallow.
If you want to run shallow, flat bottom is the way to go.

If you plan on staying in deeper rivers and lakes a V bottom will ride better and turn easier.


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