foaming the hull on a 20'???

[billythekid]

I know that the 20' is hollow with very little foam. I am planning on redoing the decks on my boat and when they are out after I redo the plumbing and electrical. can I 2 part foam the hull has anyone done it before? Will it make the boat sit higher in the water? will it affect the ride of the boat?

[NoBones]

Foam everything that you can. It cannot hurt.
When I ripped the deck out of my 20 I two part foamed every nook and crany. To sink or not to sink that is the question.
Go for it!!!!
See ya, Ken

[strick]

can I 2 part foam the hull? Will it make the boat sit higher in the water? will it affect the ride of the boat?

If you throw rocks into your boat will it make it sit higher? Question: what weighs more... a pound of foam or a pound of rocks?

Adding foam to your boat only add's weight to the boat and will effect the boat as you would expect. The only time foam gives flotation to your boat is when the boat is swamped.

strick

[GroveGuy]

I too have considered foaming the hull of my 1969 20.
My deck has held up surprisingly well over the years but when I eventually replace it would seem like the logical time to foam. My biggest concern is waterlogging, so many times I've heard complaints of "wet foam" and the excess weight that it brings with it. I'd assume it would make sense to place conduit along the keel to allow water drainage from bow to stern and compartmentally, foam over that. Trayder in his redo has some good examples of this if I recall.

I've even seen someone somewhere mention filling the hull with airtight, sealed, empty 2 liter plastic bottles!
Maybe crazy, maybe ingenious.

[ButchF20]

Hi Folks,
Although this is my first post here I have been lurking for some time. This is a topic I am familiar with. I recently replaced the foam, deck, stringers and bulkheads in a 1980 20 ft Formula. After removing over 30 lawn and leaf bags of wet foam, weighing over 1000 #'s, I thought there must be a better way. I have removed foam from several boats and thought I would try something new this time.

I ran a 1-1/2" PVC pipe in the bottom of each section that I refoamed. i drilled 1/2" holes in the pipe every 6" or so and plumbed this to empty into engine compartment (I/O).

Before pouring in the foam, I placed strips of cardboard over the pvc pipe to keep the foam from plugging the holes. My thought was similar to a French Drain system, if water ever does get in, at least it has a way out. I put expandable plugs in the pipe where it enters the engine compart to keep bilge water from backing up into the foamed areas. In the winter or trailering for a long period of time I just remove the plugs, its been 2 years now and no water as of yet.

When you look at these bioats with foam it really is a poor design with no waty yo get water out or air in. I also placed several of the pier plate covers in the deck over the foamed sections so i could see what was going on down there and get air in from time to time. So far so good and without all the additional weight removed the boat peforms unbelievably better that before. Just thought i would give you another idea to think about.

Also if anyone ever tells you that floatation foam does not absorb water, they have never done this job.

Thanks,
Butch

[GroveGuy]

Welcome to the site Butch and thanks for contributing

That sounds like a pretty sophisticated setup. How many compatrments did you have and any Pics?

[ButchF20]

It was really only two main compartments that I ran the pipe in. I have two main stringers that run for and aft, from the transome to the forward bulkhead, where the cuddy is. They about 16" high and were originally just 1 by lumber that was just mush by the time I got to it. I replaced with plywood that was liberaly soaked with resin before glassing in.

In between these stringer is where the tank would be which I also replaced. This area already had a pvc pipe in it which would allow any water in the front cabin area, run to the back. I drilled a couple of 1/2" holes in this pipe, which would allow any water in there to escape. Orriginaly when I removed the tank and foam, I had about 10" of very SWEET smelling water that had no place to escape.

The sections I put the drain in were the two that were outboard of the two main stringers, the PVC pipes were about 12 ft long and extended into the engine bilge area about an inch, where any water can be removed by the bilge pumps. I have some photo's I will have to post.

All of the dammage, rotten stringers, floor, bulkhead and pitted and leaking gas tank were all caused because water gets trapped in there with no way to ever dry out or escape. i guess when the built these boats they never expected them to last this long. The older Grady Whites are really famous for this, I know of at least six in my area that have had the same problem.

Thanks,
Butch