# Skiff Rebuild With a Foam Suprise



## bwwboating (Apr 9, 2011)

I ran into the same water problem when I started the demo on the Manatee. The front false floor and rear seats were completely full of water. I drilled holes in the rear seats and broke the glue bonding the front deck plug to the glass (why it was sealed? who knows!) I must have drained twenty plus gallons of water out of the hull. I then pulled three five gallon buckets of completely saturated wood from between the transom skins. Some people are just not very nice to their boats.

I too have been debating on cutting the rear seats out as they seem to be too far forward. My 13 year old has a hard time reaching the tiller when he has the helm. I haven't thought out what I would do though if I did. 

It will be interesting to see how you progress since our hulls are so similar.


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## DuckNut (Apr 3, 2009)

And that foam is said not to absorb water...really?


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## WhiteDog70810 (May 6, 2008)

I am with DuckNut.  I am leery of  sealing foam into areas that will never see the light of day again.  I'll still use the closed cell pourable foam, but there will be some engineering involved in making sure that it stays dry and I can get to it if I crack a chine without ripping out deck or bulkheads.  Even closed celled foam will eventually find a way to saturate if you lock it in a hole with some water and no way to dry out.

What info do you need regarding the decks?  Most of us would recommend ply/epoxy FG.  If you put the decks in flat, use 3/8" ply (marine or exterior) supported by a bulkhead or a stiffener every 16" or less.  Cover the upper surface with 6 oz woven FG cloth and epoxy for durability.  If you camber the decks, you can use 1/4" ply (marine will bend much better) with 6 oz cloth on the upper surface.  I asked the Bateau.com forum what lamination I should use for a 1/4" ply cambered deck that is supported by a bulkhead or a stiffener every 16" or less and Shine told me that only one layer of 6 oz cloth on the top is necessary.  I was surprised, but happy because it shaves off some more weight.  I've been told to use 1/4" camber for every foot of run, which is 1" of camber for a 4' wide deck.  That camber is inferred from non-marine sources that only address quickly moving rain water in a desired direction and is not based on the mechanics of 1/4" ply under compression, so it is just a number to start with.  I would make some mock ups before I committed to anything.

That looks like a neat little boat.  Enjoy the build.

Nate


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## WhiteDog70810 (May 6, 2008)

Oh yeah, since I got to you before you are in the middle of the deck construction... avoid the dimensional lumber. 2x4s, etc add way more weight than is necessary, plus they are not as straight and consistent as ply. Bulkheads and stiffeners can be 3/8" ply. 

Nate


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## PonoThe1 (Jan 17, 2011)

> I ran into the same water problem when I started the demo on the Manatee.  The front false floor and rear seats were completely full of water.  I drilled holes in the rear seats and broke the glue bonding the front deck plug to the glass (why it was sealed?  who knows!)   I must have drained twenty plus gallons of water out of the hull.  I then pulled three five gallon buckets of completely saturated wood from between the transom skins.  Some people are just not very nice to their boats.
> 
> I too have been debating on cutting the rear seats out as they seem to be too far forward.  My 13 year old has a hard time reaching the tiller when he has the helm.  I haven't thought out what I would do though if I did.
> 
> It will be interesting to see how you progress since our hulls are so similar.



Thats Incredible. I bet you removed a lot of weight!


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## PonoThe1 (Jan 17, 2011)

> I am with DuckNut.  I am leery of  sealing foam into areas that will never see the light of day again.  I'll still use the closed cell pourable foam, but there will be some engineering involved in making sure that it stays dry and I can get to it if I crack a chine without ripping out deck or bulkheads.  Even closed celled foam will eventually find a way to saturate if you lock it in a hole with some water and no way to dry out.
> 
> What info do you need regarding the decks?  Most of us would recommend ply/epoxy FG.  If you put the decks in flat, use 3/8" ply (marine or exterior) supported by a bulkhead or a stiffener every 16" or less.  Cover the upper surface with 6 oz woven FG cloth and epoxy for durability.  If you camber the decks, you can use 1/4" ply (marine will bend much better) with 6 oz cloth on the upper surface.  I asked the Bateau.com forum what lamination I should use for a 1/4" ply cambered deck that is supported by a bulkhead or a stiffener every 16" or less and Shine told me that only one layer of 6 oz cloth on the top is necessary.  I was surprised, but happy because it shaves off some more weight.  I've been told to use 1/4" camber for every foot of run, which is 1" of camber for a 4' wide deck.  That camber is inferred from non-marine sources that only address quickly moving rain water in a desired direction and is not based on the mechanics of 1/4" ply under compression, so it is just a number to start with.  I would make some mock ups before I committed to anything.
> 
> ...


Thanks this is helpful. I plan on using marine plywood with glass but wasn't sure what thickness, 3/8 is thinner than I expected... I'm unsure exactly what you mean by a cambered deck but it sounds interesting.. I tried to look it up for an example but I guess it would have an actual bend to it? I'm just unsure how high up i would like to put the deck on the gunwales. If the gunwales had a flat top placing the deck right on top seems like it would be the easiest way to go and would be add strength in addition to the bulk heads.although given that these gunwales have that curved edge i don't think it would look good. so it sounds like it as long as the bulk heads are in place and it the deck gets glassed well to the gunwales it should be strong..I appreciate the help!


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## DuckNut (Apr 3, 2009)

A camber is where the center is higher than the sides. A slight bend/curve in the deck. A cambered piece of wood is significantly stiffer than a flat piece.


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## bwwboating (Apr 9, 2011)

> Thats Incredible. I bet you removed a lot of weight!


Four of us could barely lift it up to get it on my trailer. By the time I drained the water and let the boat dry out in the garage over the winter, my 13 yr old and I can flip it over. HUGE change! Still a heavy boat.


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## WhiteDog70810 (May 6, 2008)

I'd probably camber the deck in this hull. As you noticed, if you make a deck that follows that chine, it will curve up as it approaches the bow. It will be very stiff across the width of the boat, but it might be uncomfortable to stand on and you are arcing the ply downward which is weaker than keeping it flat (...but with 3/8" ply, I suspect the loss of strength would be negligible for your purposes, assuming proper deck supports). A transversely cambered deck will stiffen the hull just as much as a flat deck because it will be epoxied to the bulkheads. It will also allow you to use lighter materials. 

I am thinking my way through the build as I write because I have nothing more pressing to do at the moment and I have the exact same job waiting for me at home. If you already know how you would do it or if you want to do something different, please ignore the rest of this post. 

I would have a bulkhead at the back of the deck (duh). I'll call it the wide bulkhead. I would also have another one somewhere 4-12" behind the cut water, depending on what looks right. I'll call it the little bulkhead. You can make them beforehand and cut the camber later. Leave them a bit taller than you think you want the deck level to be. Plans change during mock-ups. Even if you are dead sure you want the deck 15" above the sole, leave enough height on these bulkheads to allow for a 17" deck. 

I'd mock-up the deck in the hull before I epoxied it down. Make a temp center "joist" out of a 1x4 that extends from the bow level at the intended deck height that extends back to the aft edge of the deck. Get some rough deck dimensions by hand fitting a cardboard or masonite template across the joist and transfer the dimensions to the marine ply. Gently bend the 1/4 ply until it looks right and stiffens up. You'll have to hand fit it with a belt sander and Sureform as you bend it. Don't worry excessively about gaps . You want at least an 1/8" gap and 1/2" gaps are no problem. The fillet compound will also fill the "ooshit!" gaps if you make them. I have a few 1.5" gaps buried in my hull.
:-[
Start with 1" camber across the widest width and see what it looks like. Once you find what looks and feels right, ie 1.5" camber over a 50" span, scribe it to the top of your wide bulkhead. The camber should stay the same from the widest bulkhead to the bow, so you will have to scribe the curve of the top of the little bulkhead from the center of the wide bulkhead.

I am stunned at the strength of these materials, but if Shine or Jacques on Bateau say a specific scantling or lamination schedule is strong enough, I am going to listen. Most us over-build if left to our druthers (ie 1/2" ply deck screwed to 2x4's) and it takes some untraining to move beyond. Dig around in the Bateau.com How-To section. It will greatly increase you comfort with the materials and techniques.

Nate


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## firecat1981 (Nov 27, 2007)

> And that foam is said not to absorb water...really?





> I am with DuckNut. I am leery of sealing foam into areas that will never see the light of day again.


This is the exact reason I try to stay away from pourable foam. I still had to use some in oddle shapped areas, but for the majority of the areas I stick to styrofoam.
http://i50.photobucket.com/albums/f332/firecat1981/The%20Plytanic/P4110269.jpg


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## cutrunner (Jun 8, 2010)

Firecat: nice boat, is that the new one your working on or the one that got hit in traffic? And where do you find large pieces of styrofoam


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## firecat1981 (Nov 27, 2007)

That's my new one, you can buy 2" thick sheets at home depot in 4'x8' size. I have about a sheet and a half in mine, plus poured in foam in the curved front.

If you do the math 48"x96"x2" = 9216 cu. in. 

9216/1728 = 5.3 cubic feet which will float about 320lbs 

Add to that a bilge pump and a automatic float switch and you have a pretty good chance of making it back to the dock in most any situation.


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## [email protected] (Nov 18, 2010)

Great looking boat! 
Quick question, whats the piece of wood on the bow in the first picture (looks like a fence post)? Do you mount your trolling motor to it?
Have fun!
Sean


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## PonoThe1 (Jan 17, 2011)

> Great looking boat!
> Quick question, whats the piece of wood on the bow in the first picture (looks like a fence post)? Do you mount your trolling motor to it?
> Have fun!
> Sean


Its a trolling motor mount that was on the boat when I got it. Its made from one of those 2 1/2 x 4 (i think) landscaping timbers used for bordering beds n stuff. It seemed sturdy enough with the 4 through bolts!


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## [email protected] (Nov 18, 2010)

Thats what I figured.. as long as it works!
Have fun!
Sean


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