1990 Larson All American floor and stringer replacement

[brian36578]

I just bought my first boat this past fall for a great deal. It runs beautifully and the exterior is in great shape, however, the interior could use some work. The seats are in rough shape and the floor is rotted. This winter, I will be replacing the floor and stringers, rewiring some of the electrical, reupholstering or buying new seats, and possibly a few upgrades to the motor. This will be my first time replacing a floor so those of you who have experience in this please chime in with tips or links to helpful write-ups or articles. I plan on using marine grade plywood and re-carpeting the floor once it is complete. Once I get a couple more posts in I will post a few pictures.

 

[JASinIL2006]

Looking forward to some pics and to watching your progress!

 

[JASinIL2006]

Oh, and where are my manners? Welome to iboats!

 

[tpenfield]

Yes, welcome to iBoats. Lots of threads here that you can read through to get an idea of what others have done.

 

[Woodonglass]

Before you replace the floor make sure and coresample the stringers, transom, and motor mounts.

 

[brian36578]

Here is a picture of my boat. It's a 19 ft Larson All American with the 4.3L v6 Mercruiser.

 

[snowman246]

Welcome. I can tell you for sure that you will learn a lot here. Look at my project as it is very similar to your boat. I have replaced everything in mine. Look for the 1988 Glastron X-19s under projects. I have posted lots of photos

 

[brian36578]

No Title

I started tearing into the floor a few weekends ago and wow is this floor bad! On the port side and in the back, there really was no wood left. What wood is left crumbles when you pick a piece of it up. The stringers are rotten completely through and the foam is all soaked. The starboard side isn't as bad but still has a lot of rotting wood. The only dry area is in front of the driver seat. The previous owner cut out the middle section and screwed a new piece of wood in place. Anyone know of any easy way to remove the foam? The soaked foam is pretty easy to get out since it isn't sticking to the fiberglass anymore but the dry foam is pretty stubborn. I've been using a pry bar to scrap it off the fiberglass. The last pic is the progress so far after about 12 hours of work. For those who have completed redoing the floor and stringers, how many hours would you estimate you put into it? I'm just trying to get an idea of when I should start picking up the pace so it will be ready in time for summer.

Thanks Snowman. I will check it out.
​

 

[TruckDrivingFool]

With the floor out this is your next step

make sure and core sample the stringers, transom, and motor mounts.

Do that and you will know if it's time to pick up the pace to have it ready for summer.

 

[brian36578]

No Title

I made a decent amount of progress the past 6 weeks. The hull is almost ready for stringers! I have a few questions before I go any further. In the first pic you can see, the motor mounts are made of layers of plywood and are soaked but they seem pretty solid still. Is there anything I can do to prevent them from rotting or dry them out? Its kind of hard to tell in the pics but the hull is flexing inward where the boat rests on the trailer (area bowing circled in red). I don't remember seeing this much bowing when the stringers were in still and it would make sense that this would happen after removing the rigidity provided by the stringers and bulkheads. Should I try to support the boat else where so that the hull goes back to its normal shape before adding the stringers? If so, where would you recommend supporting it? I have all of the fiberglass dust in a bag from sanding the hull. Can this dust be substituted for cabosil?

 

[JASinIL2006]

If your motor mounts are soaked and you have this much of the boat torn up, why even think of doing anything but replacing them? It's only a matter of time before they rot.

 

[brian36578]

I had thought about it and have been weighing the pros and cons. I would like to get the boat finished by the beginning of May and that will set me back plus I'm a little worried about getting the engine and out-drive to line up when I put everything back together. I haven't done much research yet on replacing the mounts and the proper way of getting everything back together. Also, I bought the boat along with lots of extras for $2,000 so I need to have a cap as to how far I really want to tear into this thing and how much time and money I would like to invest although having new motor mounts and transom would be a nice piece of mind. I was also thinking of waiting till next winter to redo the mounts and transom. There is not a whole lot of time to enjoy boating here in Michigan and this will be my first full summer with my own boat so I would like to enjoy it as much as possible. Redoing it while the boat is torn down this far would obviously be the easiest route but it doesn't look like it would be too much of a problem to redo it after the new deck is in.

 

[Vintage Rider]

I think it would be false economy not to replace the transom and motor mounts now rather than later. I doubt that the additional cost would amount to more than another week of work and probably less than $200 in materials. It will cost you more in time and money to do it later and if the transom is in the same condition the floor was, doing it now could save you from losing your entire investment. By the way, where in Michigan are you?

 

[Carpenter2486]

agreed, may aswell do it right the first time, no sence doing a half job then cutting everything open and finishing the rest later, youll spend more money in the long run , would be easyer to complete the hull transom stringer resteration THEN after time safe up more money and get new motor, it is the better choice, your boat and do what you like... but it is the more calculated choice.

 

[brian36578]

The last couple of days I did some reading on aligning the motor when installing it in the boat and it doesn't seem as hard as I originally thought so I decided to pull the motor today! I will be redoing the motor mounts for sure and possibly the transom. I've pulled many motors out of cars but this was the first motor I have pulled out of a boat and it is pretty easy. I was worried if my cherry picker would lift the engine high enough to clear the back of the boat but it cleared with no problem. I will take a few core samples of the transom tomorrow. Just by doing a "knock" test with a wrench the transom seems pretty solid but I don't want to get my hopes up judging by the condition of the rest of the wood in the boat. While the engine is out, I'm going to do a good tune up on it (plugs, wires, cap and rotor and replace a few hoses). I'm also going to install a 4 barrel carb on it. Any recommendations as to what else should be replaced?

 

[mxcobra]

unless you work on the boat full time, you need to push your deadline of summer way out, It took me two years on my boat,evenings and weekends.- I had your same mindset summer summer summer. as I watched the warm weather come and go from behind my grinder.Plus transom and motor mounts isnt that much more work, and is the most important part. Along with the Bilge area. If you dont do the Bilge correct plan on another rebuild soon. Good luck and Im hoping aboard to watch the progress.

 

[brian36578]

No Title

VintageRider, I am from southeast Michigan just west of Detroit.

I pulled everything off the transom yesterday and the transom is dry! I have a few concerns though: On the starboard side, the bottom stud hole is really close to the edge of the transom and it is breaking through. Is this something to worry about and if so what is the best way to go about fixing it? On the port side, it appears the wood is coming apart from the hull, would I be able to just put some glue in there and clamp it or is this a sign that there might be some water in places I have not seen/tested?
Today after work I will be taking multiple pics of the engine mounts and about 1,000 measurements and then start cutting them out.

 

[brian36578]

No Title

I pulled the motor mounts and the rest of the deck out last night. I'm glad I decided to replace the mounts because they are bad! The transom has some bad spots on both sides below the deck surface. Is it safe to replace just part of the transom? The center part is nice and dry so I don't want to replace it if I don't have to. Also, this transom will be very difficult to replace since I do not have a whole lot of room to work because the cap comes up and over the transom and the seat frames are right there.

 

[brian36578]

No Title

Started making the cradles for the boat to take it off the trailer last night. I pulled it off the the trailer and put it on the cradle as well but I wasn't comfortable with how much it was leaning forward so I put it back on the trailer and will make another cradle for the front today after work and then I will start on removing the old transom. Here are a few pics of the cradles I made last night. For the first pic, (cradle for the rear) I will be putting a 2x4 across the 2 outer rigs. I pulled it off because it needs to have a little more height to it. The 2nd pic is for the middle. Please provide any suggestions to changes you think should be done to these.

 

[JASinIL2006]

Are you going to pull the entire transom core? Did you figure out a way to do that without pulling the cap?

It's going to be a bit more work, but I really think you're smart to do this all now. I think it would be really hard to pick up the saw and grinder again in a couple of years and tear into the boat after you did all this work. Much smarter to to get it all done now.

I don't know if you can get all that work done by your target date, but I wouldn't give up. A deadline can do wonders to help you keep at a project like this, especially on those days you just don't want to don the protective suit and pick up the grinder...

Good luck, I'm enjoying seeing your progress!