Foam issue on Aluminum Boat

stellwagen33

Cadet
Joined
Jul 23, 2010
Messages
13
Hi I have a 1970 18' center console. The make is 'AMRICRAFT' on the title, registration and on the little plate on the console. The bottom is riveted aluminum but the sides are fiberglass along with the gunwales. The aluminum and the fiberglass join pretty much at the waterline. The floor is fiberglass and between the floor and the hull is all foam. I estimate that this foam puts another 1000 lbs in the boat. I took some of it out and weighed with a fish scale and it is about 20 lbs per cubic foot. The foam is got to go. The floor is in acceptable condition. It probably will need to be replaced in about 10 years. There is no drain plug or bilge pump below the floor it is at floor level and the water just sits in the bottom and soaks into the foam. I have taken some of the foam out under the console where I have not had to cut out the floor (it was covered with plywood). There was about 4 gallons of water in the bottom of the boat and the foam is awful.
So to not completely take out the floor of the boat I was thinking of cutting some holes where I would take the foam out from and then install hatches for storage etc. I would prefer not to use foam when I put flotation back into the boat. However this is the issue. Looking at the bottom of the boat I do not see any rivets that would result from ribs inside the boat. Also in the 4 foot long area of foam that I have cleared to the bottom of the hull there are no ribs. This leads me to believe that the foam provides the structure that the ribs would usually provide. The aluminum is not very thick and the foam is snug against the hull. When it comes time to replace the flotation I would rather replace it with Styrofoam than 2 part foam. I'm thinking that the foam provides too much support. I would be willing to put some ribs or some sort of support in. Any suggestions on what to do would be greatly appreciated. Are there any aftermarket rib companies...? Do I put something like stringers in, but its aluminum. I have been trying to do research on this the past couple days but since the hull is aluminum and with no ribs and just foam, I haven't found anything so I'm here looking for any suggestions on what to do. Thanks in advance.
 

Bob_VT

Moderator & Unofficial iBoats Historian
Staff member
Joined
May 19, 2001
Messages
26,097
Re: Foam issue on Aluminum Boat

Welcome to iboats.

That foam sound structural. I suspect the entire deck needs to be removed.

We will need pictures of that hybrid boat. ALuminum mixed with fiberglass is rare.
 

stellwagen33

Cadet
Joined
Jul 23, 2010
Messages
13
Re: Foam issue on Aluminum Boat

My bad, the whole boat is aluminum, just the floor is fiberglass.
The picture is under the console of the boat. The 2 by 4 looks like support for the deck and is rotted and will need to be replaced.
 

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