Stringers On A '68 Larson

[RandomNoise]

I've got a '68 Larson. Not sure what model, there's a model number on the plate and I'll post that later. But it's a 17' closed bow runabout with a Mercury 1000 on it that seems to have been purchased with the boat.

The center of the carpet was gone and the exposed plywood was coming apart. When I stepped on the edges of the deck there was a nasty crunching sound and my kid could see my foot sinking quite a bit. After pulling up the carpet we found that someone had previously replaced the deck. Please understand that I know nothing of boats or boat repair but it was easy, even for me, to tell that their work was.....let's just say "inferior" to be nice. They had only glassed around the edges of their repair and most of that failed to stick to either the plywood or the original glass of the boat.

I have one section of the deck yet to pull out back by the transom. That's because their fiberglass work in that area appears to have been good and I need to cut it out this week. All the rest of it just pulled up by hand. If I'm not mistaken, it looks like they must have done a transom replacement because that glass looks different than the rest of the boat and the transom sounds and looks quite solid.

So I know that I need to do the deck for sure.

The deck repair seems to have been held down with some sort of caulk or adhesive (not much of that) to the stringers. Additionally they put four deck screws through the deck and into the stringers. Those screws wouldn't back out with the screw driver, they just spun. I pried them up with minimal effort. Now I'm alarmed about the stringers. Was it just rot around the screws or are the entire stringers shot? Obviously I need to inspect and learn more.

But nearly everything I've read and seen online regarding stringers is different that what I'm looking at. I'm not finding much out about this particular boat. Before I go exploring these things I would like to have a general idea of what they are, how they are constructed and what I should be doing to them.

Based on the few photos I've seen online and the minimal comments about them, I am making an assumption. All I can see is wood on top that is encased in a very coarse fiberglass mat. Not all of the wood is encased, there are a few exposed inches across the very top. Is it possible that these are 1" by 10" boards that lay flat on top of several inches of some sort of foam? If so, and if the wood is bad, do I need to simply cut off that top inch of glass and wood then replace with wood and glass it back down?


Thanks in advance to anyone reading this lengthy post.

 

[frozenokie]

Re: Stringers On A '68 Larson

I did a complete rebuild of deck, stringers, foam, etc. on a 79 Laser bass boat several years ago. First, I want to say that in dealing with stringers and decking, it will be much more beneficial to use the right materials and constructing them in the right manner to get desired results and integrity or strength.

In my opinion, after looking at your pics, the previous attempt at repair was less than appealing and satisfactory to say the least. That's why it has to be done again. The best approach, again in my opinion, is to rip out all the decking and foam first and evaluate the stringers and their size(s). One of your pics looks to show that the bilgeway is blocked off by foam in the bow area - which is a bad deal because it won't allow any water to drain through the bilge area to the back of your boat where it can be pumped out or drained through the drain plug. Leave a clear pathway for water to reach the back of the boat when constructing your new deck and stringers.

Stringers are the backbone of your boat. So, if it were mine, I would plan on replacing all stringers, foam, and fiberglass. This is a real undertaking and will take some time to get it right. You won't know what size of timber to use for stringers until you take out the old. Use a light wood that is also very stiff and without knots or as few knots as possible. I used Poplar 1x's since they had few knots, were lightweight, and very difficult to bend or split. There is a two part, "A" & "B", for mixing up your "pour" foam when you get the stringers glassed back in the hull. You can find it online which is what I did and it worked great. Be sure to calculate what cubic feet of foam you need to keep your boat afloat. You can also find the formula for this online.

I used 1/2" ply but chose not to use treated since I knew ahead of time that the fiberglass resin/matte will bubble up when applied to it. It will be the best result to glass both sides of the deck to make it last a very long time and not soak up water. Once the deck is sized right, mock fit it up to your stringers by laying it in place and marking lines where your stringers are underneath it. Always "test" fit your stringers to your hull shape before starting final attachment. I used a carpenter's chalk line to mark the centers of the stringers so I could place screws in the center of the stringers without breaking through the sides of the stringer underneath. Be sure to use all stainless steel screws too. Pricey, but they wont rust out. Apply a little fiberglass resin on top of the screw heads when done to keep water out. Then glass in the perimeter of your deck to the hull using matte and resin. Keep in mind that using at least two to three layers of matte is best without getting too heavy. I used three layers everywhere except on the decking, which is where I used two layers.

You may want to install one or two deck drains in the area of your bilgeway to allow water to drain right into the right bilge path below. That way any water or rainwater can easily find it's way to your bilge pump and not "stand" on top of your decking.

I hope this helps some. As for my completed Laser, it was a solid restoration of a boat that was on the verge of going to boat heaven. GOOD LUCK and post pics when you can. I always like seeing the progress of these types of projects.