What I did was to glue the foam blocks together with Liquid Nails.  It takes about a week for it to fully harden but it is cheap  ($6 for 2 tubes).  Then shape it with a sanding block of 80 grit, radius the edges, and cover with 1 layer of 6 oz cloth.  There is more than enough from the kit.  Further 1 -2 coats of clear epoxy and you're done.  Light sand with 220 and paint color of your choice.  I painted mine a sand color, the same as the inside of the boat. So far it has held up well, even with feet against it.

I suppose you could veneer it, but then it requires a coat of varnish and will need varnishing all the time to look good.  No thanks.  Paint is easier to put on, clean or repaint. But this is what makes the world go around.

Agree with Adm. Sink about the varnish and paint. If I were to have a do over I'd use graphite + epoxy to cover foam, with or without glass. Glass, (only on exposed face) would be more durable. Graphite filled epoxy eliminates need to paint and is very easy to repair. Also, I've made so many modifications I'm getting a little sensitive to weight and the wood veneer would add a bit more. 

I used black (the charcoal color specified in the order just about equals black) closed cell foam. I'd do it again, and in fact just added some semi-permanent side seats with foam under them.  In net, I believe it will cost just a bit MORE, with just a bit LESS total work, to use closed cell foam, but when done it looks very nice, will last a very long time, and will be unbreakable, maintenance free and virtually indestructible.  I press my feet up against mine just as hard as I like when rowing or bracing when heeled over under sail.  I've noticed (seeing as it is basically the same stuff as pool noodles (but denser and more durable)) that long term direct exposure to sunlight will result in U/V degradation, but I'd only worry if I expected the boat to be out in direct sun without a cover for many years.  

The foam might look a little pricey, but perhaps not so much when you add the total expense of the alternative (styrofoam, glass cloth, epoxy, sandpaper, paint).  You can buy foam from:

Foam Factory Inc · 17500 23 Mile Road · Macomb, MI 48044 US · [email protected] · Phone: 586-627-3626 

Here is what I bought most recently to make some additional floatation for my side seats,

Product Quantity Price Subtotal

2.2LB Polyethylene - 54x24 - 2" 

PECOLOR: Charcoal  $43.99 

but if memory serves me right I bought different thicknesses so that gluing the two pieces together resulted in the correct total width to go under the athwartship seats.  The max thickness you can buy is 2 inches, but you can get 1/2 inch increments from .5 inch to 2 inches thick. (All sizes are made from 1/2 inch thick sheets, even when pre-glued by the factory.) For instance, if you want something 3.5 inches thick, buy pieces one piece 2 inches thick and one piece 1.5 inches thick and glue the sheets together prior to cutting them to shape for use.  You can use some 3M super strength spray adhesive or plain old yellow contact cement to glue sheets together, with a board and plenty of weight on top.  Both types of glue seem to work fine - the contact cement actually seemed better to me.  Always spray or spread on both sides to be glued.  I then used a clear acrylic adhesive caulk to stick the shaped pieces under the seats.  The foam can be installed with seats off (leaving the proper center gap) or with seats in place, by shimming between the foam and hull bottom to create a lot of upwards pressure (so long as you don't go crazy with the caulk so that squeze-out doesn't stick to the athwartships rib. You do need to leave the same gap as specified in the plans (1/2" ?) to allow water to flow freely under the floatation.

A friend of mine painted them black and then glued open cane webbing on, made for a classic look. 

George K

Hi I had the same concern.  I took extra plywood from build and glued it to polystyrene and then varnished it. Much better looking and more durable  the polystyrene painted black. 

We followed the manual to the letter and shaping styrofoam for the flotation on our NE Dory was the part of the build we enjoyed least. As for the end product ... still functional, but looking rather the worse for wear. Admittedly we're hard on our stuff. I don't think we'll ever remove any thwart, and I'm wondering about building water-tight boxes under the thwarts with okume facing, possibly with some access points, and keeping some kind of channel for water to slosh through... not that we've ever had much in the boat but might be useful if we ever need to bail ... knock on wood.

I like John's idea to build little watertight boxes. We may make that modification at some point. 

Our NED has only been floating for a few weeks now, but we've already got a number of dents in our epoxied-over foam. We've got tons of cloth leftover from the build and, if doing again, would simply glass on a layer before painting. It wouldn't add much work to the build as the manual already calls for layers of epoxy. 

In our case, we put three coats of epoxy over the foam, then painted with leftover polyurethane paint from the hull (in our case off-white). It ties in well to the overall aesthetic.  

Update: we've had the dory out a lot this summer and I've now completely broken off two of the under-thwart styrofoams. I can't help kicking them when I'm scrambling about on a tack change for example.

   And thus my vote (again) for the closed cell foam.  Virtually indestructible - stab it with your steely knife and you just can't kill the beast. Scuff it, whack it with an oar, tear a chunk out of it with the hooks on your Rapala, whatever, it still looks basically the same. Both the foam and the adhesive caulk used to attach it uner the seats are flexible enough that (if you keep the gap between foam and under seat rib/bulkhead relatively small) you can brace your feet on it as firmly as you'd like without any fear of dislodging it.  Maybe a project for this winter if you're up for it.  With all materials in hand, an hour to glue the sheets together, then after allowing the lamination to dry for a day or so, a few hours to shape the foam and glue to the seats.

Again, my two cents here and I woulnd't have bothered with the following comment except that I revisited the thread to advertise for the closed cell foam:  I don't like the idea of "watertight" boxes or compartments anywhere on wooden boats.  I think that sooner or later water always finds a way in, and without ventillation (like one of the watertight hand-hole ports you can open when the boat is not in use) you're running the risk of rot.  Plus, building wooden floatation boxes seems like an awful lot of work for this application (when you could be using closed cell foam).

   I got nothing to add but a story. 

A little more than fifty years ago we used to keep a row boat at the lake. It was stored upside down near the dock. It got cold in Indiana in the winter time. The boat was not special but had foam flotation under the seats, thwarts. 

It seems foam is a good insulator and home for critters. 

One spring we popped that boat upright, slid it into the water and boarded for a quick row across the lake.  My grandmother and I liked that boat. Well it seemed that field mice liked it too. Maybe 20 feet from the dock they started coming out of the nest in the foam seat flotation under grandma. Panic, screeming and pandamonia erupted as the six pack ran for the safety of the shore line amid the swats of hats and other objects of mice eviction.  They swim pretty good. 

In the least  make the foam mouse resistant. 

Do you even need the foam? On the face of it, it's a wooden boat and wood floats. Presumably the passengers and crew can swim, have PFDs, etc., so they float. What does the foam accomplish? Is it to keep the sheer above the waterline when swamped? Or is it just a regulatory requirement to keep the Coast Guard happy?

Laszlo

   I just want to say thank you to the person posting abou the closed cell foam. I am at the point I need to add the floatation and was in a quandry about what to use. I didn't want to use the building insulation.. even if I cover it with Fiberglass.. It just doesn't seem like  a good way to go.

My plan is to cut this closed cell foam to fit with a gap between it and the floor deck. I plan to use silicon to glue the foam to the actual thward, not the underside of the seat. This way it will stay in place, I can push on it with my feet to no effect and If I have to remove a seat the flotation stays there.. seems the easiest way to go.

   Laszio

The coast guard requires that all boats have a certain amout of posative floation. I am dubious about the wood floating after we put all the epoxy and paint and fiberglass on it. I would not want to dump the boat over only to find that the small anchor I have is enough to send my boat to the bottom instead of it floating happily. Also with floatation you have the possability to self rescue if you dump the boat over.

Hi Pat,

An epoxy/glass layup ends up with pretty much the same density as water, so it's neutrally buoyant. It doesn't affect the ability of a flooded boat to float.

On the other hand, it seems that you're right about making self-rescue easier. Last night I remembered Silver Salt's posts about the caspize tests that the did with his NE Dory. He said that the extra flotation does in fact make the sheer float higher above the water and makes draining the boat easier.

So I guess there's a reason for adding foam instead of just relying on the boat's natural flotation.

Laszlo

   Super appreciative of the closed-cell foam recommendation as well. 

And the follow up recommendation to glue to thwart rather than seat. Seems some mention (from Silver Salt posts link above) that the bouyany on the seat will cause the seat to pop off. Float the boat, not the seat makes sense.

Questioned the durability of the foam floats from the get-go. Confirmed my suspicions when my cut, epoxied, black spray-painted floats were left in the Las Vegas sun to dry and they melted in a few hours. 

Closed-cell foam all the way for round 2. Thanks,

Joe

   Note of clarification: I've taken my seats off a lot and had enlarged the screw holes in that soft pine. My remark was more an indication of how much positive buoyancy the foam provides. Installed seats with #10 screws and coated screw holes with epoxy. Worked a treat.
I’ve knocked flotation blocks off too. Reapplied with polyurethane glue. Seems to be working well. Might try 5200 next time but that would be a mess to repair.
Had I known then what I know now I’d have added graphite to final coat of epoxy and skipped painting. Would have also skipped epoxy coating on non visible areas of flotation. The graphite epoxy would be super easy to touch up when the ugliness ratio goes too high.

Floatation test part three is coming up before long. I added lowdown tiedowns for use with Watershed dry bags. This should more than double buoyancy in the stock boat. Pretty sure it will make the boat easier to empty by displacing water. Not sure it will make the boat float much higher. It’s sure warm enough to test these days!

What do you mean by "closed cell foarm"?

What's recommended and what I used is molded sheets for building insulation. It's expanded polystyrene (EPS) made of pre-expanded polystyrene beads.

EPS (aka "styrofoam") is closed cell foam.

The polyethylene closed cell foam recommended earlier is different than builder-store EPS or XPS (those "PS"-es stand for polystyrene, either extruded -E, which is usually white and in low density formats has those beads and is called Styrofoam, or expanded -X, which is the usual pink stuff. If you're at all environmentally careful, you'll avoid the XPS unless its unique properties are actually needed, due to the very damaging blowing agent used in its manufacture.).

Polyethylene foam is basically the same foam as pool noodles, but in a denser format. I'd be curious to hear how the denser black material holds up when left exposed- my experience with pool noodles is that weather turns their surface to powder in about a year.

   I'm the person that has a couple of unattributed posts on this thread - the one that gave the sorce for the polyethelene foam in Michigan.  I've had the foam in my dory for 3.5 years now.  I'll grant you the boat is garage kept, and therefore only sees the sun when in use, which is typically 2 or 3 times/month, 4-6 hours outside of the garage per outing.  So that doesn't really equate to very many hours in the sun. However, the garage here in TX is very hot all summer, so there's that.  Also, the foam seems to be significantly better quality than pool noodles - denser, with a smooth "skin" surface - and unlike a pool noodles where if you sqeeze it hard and get a "permanent" dent, this foam doesn't deform easily.  So anyway, after 3 years I can't really tell the foam from new.  Still highly recommended by me.

Thanks. I'm in Canada. Does this look right? (Search polyethelene foam on amazon.ca).

PROTIP Bubblehead, when typing a reply, after an unknown period of time your login "session" times out and your post goes in as "Submitted by -" If you need time to compose, do it in notepad or somewhere ...

 Yeah, the time-out has caught me a few times.  Dinner, barking dogs, whatever.  I'm not really concerned when unattributed.  Anyway, no, the neoprene foam at the Amazon link does not look right.  Neoprene foam will be much softer and more prone to being torn by things poking at it.  Most importantly, I'm sure that it will be quite a bit heavier.

The link below has the correct stuff on Amazon - it doesn't say the exact density you're getting, but it will probably be good. This is the type of foam used in quality packing, like when you get a box with (for example) 6 stage microphones in it, all with individual shapes cut out to protect each individual mic.  (Or, in gun cases, like everyone at the Amazon link comments is talking about.) So, this Amazon stuff should work.  Make sure to stick with the polyethylene, not polyurethane.  I just checked measurements, one 54x16x2 inch sized piece should do one side of the center seat with little waste, as you can cut lengthwise and glue together to end up with a blank chunk 54x8x4 inches.  The 4 inch thichess is just right to come out to the edge of the seat.  You can go 1/2 inch thinner if you want it slightly recessed under the seat lip, but I wanted max possible floatation.  Things do get expensive, so you can lay what you need out on paper to buy the right amount while minimizing waste.  It is OK to butt-seam the pieces if desired, and when laying up thickness, offset the seams so they don't line up, like this.  Or if you want to spend more, just buy more and avoid the butt seams.

xxxxxxxxxxxxxxxzzzzzzz

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https://smile.amazon.com/Case-Club-Closed-Military-Grade/dp/B015JRXH1W/ref=sr_1_2?dchild=1&keywords=polyethylene%2Bfoam&qid=1591621464&s=sporting-goods&sr=1-2&th=1

You might want to price out the factory rather than Amazon, the price below gets you a bigger (24 inch wide) chunk for less money, not sure about shipping.  You get more choices with size, density and color and things might be cheaper.  You can get the foam below in differing densities - the less dense, the more likely to "dent."  I didn't search to see if there is a Canadian equivalent company somewhere, but at least this is close to the border.    Below is what I purchased. 

Foam Factory Inc · 17500 23 Mile Road · Macomb, MI 48044 US · [email protected] · Phone: 586-627-3626 

Here is what I bought most recently to make some additional floatation for my side seats,

Product Quantity Price Subtotal

2.2LB Polyethylene - 54x24 - 2" 

PECOLOR: Charcoal  $43.99 

And having gone out to measure the boat, I probably timed out agian this time, we'll see.

   Just making a post so that the thread gets logged with a new post in case John C. was watching for one.