1979 MFG Morrison 20' with spongy floor and mystery leak

Big Keepers

Big Keepers

Petty Officer 1st Class
Joined
May 13, 2007
Messages
293
So this was a free boat given to me a few years back. I fixed it up here and there cosmetically mostly, rewired, steering, etc. It still needs a lot of work though. What I'm unfamiliar with is the exact way MFG built their boats aside from taking two molded fiberglass sections and mating them together. I know that the gas tank hold and the "bilge" are structural to the top molded piece and that there is a void below that can trap water. There is an access hole that you can see through from the cuddy cabin and there are wood stringers I believe but I didn't see too much foam there. While it was stored at my uncle's, the cover ripped and racoons decided to live in their for a while (that was cleaned out as best as I could get it). When I rode the boat it felt solid. The floor has one or two spots that feel a little spongy. Again I'm not too sure how these were built.

The leak is my concern. I put new thru-hull scuppers in the rear both in the floor and the bottom of the hull. The old hose that was in there was this rigid, almost like fuel line or old coolant hose type of material. It looked like junk so I replaced it with hose that was rated for below water installs. The issue I had then was the amount of space to work in (next to none) and the fact that I needed like 8" lengths to connect both thru hulls. I suppose the connections here could be my leak. To try and find it I filled the void with water a few times, I even cranked the trailer tongue down so the water sat in the bow to see if leaks showed in the bottom of the hull. I never saw any.

Before I go ripping this thing apart for no reason I'm looking for suggestions. Input. Knowledge of how MFG built the Morrison line.

Thanks.
 
Big Keepers

Big Keepers

Petty Officer 1st Class
Joined
May 13, 2007
Messages
293
So I e-mailed MFG directly trying to see if they had any information on this line of boats still and was informed that they did not keep bills of materials for that product line and none of the team members who made the boats are employed there any longer (which I figured). The person did say that the wood they used could be OSB, plywood or pine dried well as they use those materials to this day when building out of fiberglass.

I was hoping to find some kind of specifications or schematics as to how the boats were laid out, where stringers were run, how the fiberglass was laid in the molds, etc. Looks like the search continues.
 
ondarvr

ondarvr

Supreme Mariner
Joined
Apr 6, 2005
Messages
11,527
Those kinds of details are rarely available on new boats, let alone one that's decades old. It doesn't matter much though, because even if they had something on paper it doesn't mean the workers followed the plan. Plus most boats are very similar once the decals are removed, just read some of the other similar threads and you'll get a good idea of what's going on. After that you'll have questions on your exact situation.
 
tallcanadian

tallcanadian

Captain
Joined
Sep 7, 2006
Messages
3,250
About the only thing I can suggest is learn as you tear it down. There are no plans with these old boats. I would say that more than. Likely the stringers and transom both will need to be replaced. Don't worry about specs as far as materials go. As you read others posts you will see that most stringers and floors (decks) are built with similar wood sizes. As we build, we can usually makes these stronger than factory. And when it's done it will outlast you. Lol. What size motor you got on this.
 
Big Keepers

Big Keepers

Petty Officer 1st Class
Joined
May 13, 2007
Messages
293
The boat has a 200hp Yamaha on it. It was rated for up to a 225hp motor. The one that was on it was a 175hp Evinrude.
 
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