1970 Mirrocraft Titan 15, no stringers? Foam for structual support?

[Roadblock]

I bought a 1970 Mirrocraft Titan 15 as a restore project a couple years ago.

Transom has been replaced. New deck, new seats etc.

When I had the old desk out I found the whole hull was pumped full of foam and it was all wet. Everyone suggested I pull and said it would make the boat faster because it would be lighter.

As I was pulling the foam I was not seeing stringers. I got a good section in the back pulled up and saw no structural support.

I stopped and emailed the VP of Mirrocraft and he replied saying that in 1970, that boat had no stringers, it used something they call "life foam" made by DuPont. Basically that two part foam stuff, but he did not remember the weight used.

Also the foam seems to have coating on it. Almost like the hull was sprayed with something like Gluv-it or something prior to the foam being injected. I'm guessing to seal it.

ANYWAY I hadn't take so much foam out that I could not use the boat so I just let it dry out for a couple months while I did other stuff and than laid new deck.

Time has come that I want to figure out what to do next. Can stringers be added or should I just pull the foam, Gluv-it seal the boat or something similar, re-lay the deck and take it somewhere to be foamed?

I would almost rather have stringers so so I can just pump out the water that gets down there but maybe I'm looking at a major project to add them? Hell might be easier to just find a new shell of a boat without foam and transfer my motor?

I do have a closed bow boat and I would almost prefer an open. Maybe I can just find an aluminum shell and transfer? Not sure what to do.

 

[Woodonglass]

Lot's of hulls back then were Foam Filled hulls with no stringers. You can still do it now. Just remove all the foam, put the new deck down and pour new foam. The foam creates it's own protective film when it cures. You'll want the 4 lb density. Figure your cubic ft and order the proper amount.

 

[Roadblock]

So your saying I can pour the foam myself? I thought it required special spray guns?

How hard does the foam expand? Like, my concern is the foam forcing the deck up. Best I can tell, the deck, even the factory installed one wasn't screwed down.It was made from 3 sections of wood with two cross supports that the flooring was screwed to but the deck itself wasn't screwed down to the boat.

It was just suspended there and then the foam filled the gap and added stability.

I know some of that foam stuff really expands hard and forces stuff out. The previous owner of the boat filled the gunwales with foam and it bulged them out big time. I had to rip the foam out and pound them flat on the sides with a rubber mallet.

ONE LAST question!

So this boat isn't super big but it's heavy enough that I won't be able to get it off the trailer in my garage. I have an EZ-Loader trailer with those rollers on it. I wonder if the boat will be ridged enough that I can rip the foam out and re-pour it ON the trailer. My concern is the hull flexing and leaving big dents in the bottom of the boat or will the foam push them back out?

I suppose I could take it to a local lake and drop it in the water so there is nothing pushing on the hull and then pour it right there while floating. I know that stuff expands pretty fast.

Any suggestions would be great!

Also what brands of foam should I be looking at?

 

[Woodonglass]

You will install the deck first and glass it in. You will then calculate your cubic ft. The foam expands at a calculated rate of expansion so you can get very close to the amount of mix needed to fill the area under the deck and this will avoid any undue pushing on the hull. U S C O M P O S I T E S . C O M is a great source for the foam. This Video is one of the best for explaining and showing how it's done.

Roller trailers are NOT the best for working on a boat. You'd need to either build some "Bunks" to fit under the boat or build a separate Cradle and move the boat to it for proper support. As you say, it WILL want to Warp a Bit if not supported properly. You MUST take a bunch of measurements prior to demolition and then use straps and support to ensure the hull stays in its original shape during the rebuild process. It's not as hard as it may sound but it does take a bit of time and thought to make it happen.:joyous: