# Cleat mounting



## llbaker2

I just got a Blazer 1752 Standard with the flat heavy duty gunwales. I need to mount some cleats for docking etc. I originally planed to attach cleats using SS screws but I read that just attaching cleats to gunwales with SS screws is not a good idea. Better to use machine screws and nuts with backing plates. Is it possible to use machine screws an backing plate on the flat Blazer gunwale? If so, how would one go about doing that? Guess what Im really asking is what is the best way to mount cleats on Blazer with flat HD gunwales?

Also like some input on whether I should go with a 4" or 6" cleat. Was leaning toward a 6" nylon.


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## bcbouy

i'd go with rivnuts,machine screws and thread locker.


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## DaleH

bcbouy said:


> i'd go with rivnuts,machine screws and thread locker.


Rivnuts - if aluminum - IMHO aren’t strong enough to hold a cleat worth holding your boat with ...

A cleat is a high strength item, sometimes a safety item (towing, anchoring to avoid a bigger issue etc.) subject to tremendous shear stresses! I’d only through-bolt them, with backing plates and using SS hardware. Put adhesive-lined heatshrink or el-tape over the bolt body where the SS fastener pieces thru the tin and if your backing plate is metal, put nylon washers or more el-tape under the SS washer before the nut.

Never put SS fasteners or hardware in direct contact with aluminum, or the galvanic corrosion will eat away at the tin ... made 10X worse if/when boating in the salt.


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## Scott F

I have to agree with DaleH. I used to use rivnuts on the job but I'd never trust them to hold under any kind of stress. I recently bought a new Blazer 1648 which is probably basically the same as the 1752 but I don't quite understand what you mean by "flat heavy duty gunwales" Could you provide a picture? I'm considering adding cleats myself. What I plan to do is to add them mounted just like the oar lock that is on the boat now.


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## ppine

Cleats can be under a lot of stress during towing or a storm or some other conditions. When a nylon line streches and then a cleat lets go it can become a projectile. The best way to mount a cleat on an aluminum or steel boat is to weld it to the deck. The second best way is to bolt it to the deck with a backing plate and large fender washers. Use some decent sized bolts and lock nuts. Don't mess around with cleats.


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## bcbouy

funny.my brand new boat came with s/s bolts and nylon cleats,but i guess you guys know better.of course a docking cleat will fail if you try and tow with it.no matter how its secured.it's not designed for that amount of shear stress,and i defy you to show me a cleat that failed from using a riv nut or a nutstud.


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## jtf

These are welded bow double eyes, no problem with snagging fishing line. Shop suggested welding to the side seams for strength, at a corner to prevent shear.

The company has both weldable cleats and small and large bow eyes, not expensive. https://www.dierksanchors.com/products.html

Have seen the cleats with a full flat plate foot, weldable on 4 sides. This isn't a close up, best pic I had to show the cleat.


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## llbaker2

DaleH said:


> bcbouy said:
> 
> 
> 
> i'd go with rivnuts,machine screws and thread locker.
> 
> 
> 
> Rivnuts - if aluminum - IMHO aren’t strong enough to hold a cleat worth holding your boat with ...
> 
> A cleat is a high strength item, sometimes a safety item (towing, anchoring to avoid a bigger issue etc.) subject to tremendous shear stresses! I’d only through-bolt them, with backing plates and using SS hardware. Put adhesive-lined heatshrink or el-tape over the bolt body where the SS fastener pieces thru the tin and if your backing plate is metal, put nylon washers or more el-tape under the SS washer before the nut.
> 
> Never put SS fasteners or hardware in direct contact with aluminum, or the galvanic corrosion will eat away at the tin ... made 10X worse if/when boating in the salt.
Click to expand...


What is el tape? Only thing I can find is electroluminescent tape. Dont see how that would help. Must not be what you are talking about. If you have sacrificial anodes mounted in various spots is galvanic corrosion still an issue? Like the idea of adhesive-lined heat shrink. My issue is trying to mount cleats on flat heavy duty gunnel. Gunnel is extruded aluminum molding about 1 1/2 - 2 inches wide and 1 inch thick
attached to the top of the side of boat. Not sure how practical it would be to thru bolt the gunnel. Not much room for backing plate other than some small finder washers and cleats would have to be offset to inside or outside since "vertical" side of boat "Ts" with gunnel at its center.


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## llbaker2

Scott F said:


> I have to agree with DaleH. I used to use rivnuts on the job but I'd never trust them to hold under any kind of stress. I recently bought a new Blazer 1648 which is probably basically the same as the 1752 but I don't quite understand what you mean by "flat heavy duty gunwales" Could you provide a picture? I'm considering adding cleats myself. What I plan to do is to add them mounted just like the oar lock that is on the boat now.



I dont have access to the boat right now. Having a hard time finding sample picture. I attached a image of a canoe with very similar gunwale. Its flat on top rather than round like a pipe. Its about 1 1/2" - 2" wide and about 3/4" - 1" thick. Look pretty much like the one in photo.


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## DaleH

llbaker2 said:


> What is el tape?


Electrical tape ... it works, as all it does is INSULATE the stainless steel fastener from the tin.



> If you have sacrificial anodes mounted in various spots is galvanic corrosion still an issue?


Yes, as metal-to-metal actions between dissimilar metals is galvanic corrosion. Those anodes you're talking about prevent electrolysis.

*Electrolysis *is the forced introduction of an electrical current in an electrolyte (water, or even worse ... SALTwater) that causes a chemical reaction that separate the components of metals into the water, where the less noble metal gets eaten away.

*Galvanic Corrosion* is a form of electrolysis, in that it too is an electrochemical reaction that causes electrons to flow from the less noble metal to the higher noble metal, but occurs locally at the site where the 2 metals touch each other. See the chart? The farther away the 2 metals are on the chart, the more the corrosion can occur.

It ain't rocket science, heck when I first learned of this topic I just added duct tape under the heads of SS washers. Took a boat apart (used in saltwater) many years later and all was fine. Nowadays I've just 'refined' my build techniques and use the little bit more elegant solutions of nylon washers and heatshrink. Regardless of the material used - insulating different metals from each other works!

Shear Strength
While we're back on this topic last night ... I looked it up in my engineering books and SS through bolts in 10-32 or 1/4" sizes offer shear and tensile strengths > 6X times that of comparable sized rivnuts, and pull out strength far, far greater, as an FYI.


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## llbaker2

DaleH said:


> llbaker2 said:
> 
> 
> 
> What is el tape?
> 
> 
> 
> Electrical tape ... it works, as all it does is INSULATE the stainless steel fastener from the tin.
> 
> 
> 
> 
> If you have sacrificial anodes mounted in various spots is galvanic corrosion still an issue?
> 
> Click to expand...
> 
> Yes, as metal-to-metal actions between dissimilar metals is galvanic corrosion. Those anodes you're talking about prevent electrolysis.
> 
> *Electrolysis *is the forced introduction of an electrical current in an electrolyte (water, or even worse ... SALTwater) that causes a chemical reaction that separate the components of metals into the water, where the less noble metal gets eaten away.
> 
> *Galvanic Corrosion* is a form of electrolysis, in that it too is an electrochemical reaction that causes electrons to flow from the less noble metal to the higher noble metal, but occurs locally at the site where the 2 metals touch each other. See the chart? The farther away the 2 metals are on the chart, the more the corrosion can occur.
> 
> It ain't rocket science, heck when I first learned of this topic I just added duct tape under the heads of SS washers. Took a boat apart (used in saltwater) many years later and all was fine. Nowadays I've just 'refined' my build techniques and use the little bit more elegant solutions of nylon washers and heatshrink. Regardless of the material used - insulating different metals from each other works!
> 
> Shear Strength
> While we're back on this topic last night ... I looked it up in my engineering books and SS through bolts in 10-32 or 1/4" sizes offer shear and tensile strengths > 6X times that of comparable sized rivnuts, and pull out strength far, far greater, as an FYI.
Click to expand...


DaleH thanks for your time and guidance. Just the kind of info i was looking for. Guess if I cant thru bolt to top of gunwale I could mount cleats to inside of vertical side wall inch or so below gunwale. If I go that route think I will use a piece of aluminum bar stock (around 1/16" - 1/8") rather than washers as back plate. May put plate on both inside and out. Use heat shrink and fill holes with 3M 5200 Marine Adhesive and nylon washer to further insulate metal types. I might be able to mount cleats near outside edge of gunwale in such a fashion that still have room for nuts and backing plate. Think I will only have about 1/2" of flat area (gunwale is rounded on the sides, flat on top and bottom, sort of a flat oval if that makes sense) to accommodate backing plate and nuts. 

Debating between 4" and 6 1/2" nylon cleats. Fear 4 inch might be to small. Leaning toward 6 1/2 which might be a little overkill but guess that wont hurt anything. Got any input on cleat size? Im talkin bout a 1752 aluminum flat bottomed shallow water jet boat. Not a big boat.


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## llbaker2

DaleH do you know anything about Tef Gel (https://www.ultratef-gel.com/tef-gel-product-reviews/). I hear its a sticky coating that can be applied to stainless fasteners when used with aluminum. They claim it solves galvanic corrosion issues. Not sure if it works on screws or if it just gets squeezed out when you tighten screw.


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## richg99

Cleats.....bigger are better..IMHO


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## DaleH

llbaker2 said:


> DaleH do you know anything about Tef Gel (https://www.ultratef-gel.com/tef-gel-product-reviews/). I hear its a sticky coating that can be applied to stainless fasteners when used with aluminum. They claim it solves galvanic corrosion issues. Not sure if it works on screws or if it just gets squeezed out when you tighten screw.


Yes, very familiar with it! *It really works!* 

It was developed for the US Navy to prevent galvanic corrosion on their ships as there’s a ton of tin hardware bolted on their steel hulls. When I actively ran (still own it) my www.classicparker.com website they offered to send me some to test and use, but for the average guy ... it is co$t prohibitive, so I passed on their offer (although I certainly appreciated it!).


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## jethro

I didn't even use rivnuts to attach my rod holders and downriggers! Surface welding the cleats to flat aluminum sheet may sound strong, but it's not. You want the cleats through bolted with a backing plate for sure, as it was factory done on my 2100. I actually had to cut access panels in my hull to get the rear rod holders through bolted, but it's done right and done forever.


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## bcbouy

yeah, they're just like an oversized rivet anyway.good thing our boats don't have any of those pesky rivets right?.


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## jethro

bcbouy said:


> yeah, they're just like an oversized rivet anyway.good thing our boats don't have any of those pesky rivets right?.



Bucked rivets are a whole different animal than friction fitted rivnuts though. You'll never see a manufacturer of quality, riveted boats like Lund using rivnuts (or even bucked rivets) to attach cleats to flat aluminum plate. They always through bolt them with backer plates.


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## ppine

If I found a new boat with nylon cleats, or steel cleats screwed to the deck I would run the other direction. 
It tells you a lot about the construction that you cannot see. 
I like welded aluminum boats with welded cleats.


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