How to tell if hollow stringers are bad? 20' 1969

[69Seacraft20]

I'm trying educate myself on seacraft hull frame construction. After doing some searching here I've found that my 1969 seacraft stringers are hollow. I'm not sure how they can rot.

If I were to remove my deck and inspect the stringers, what should I be looking for?

If they are not cracked or delaminating is it safe to assume they are fine?

Should I drill tiny (repairable) holes to check for water?

Thanks

[NoBones]

I have a 1969 & 1970 20SF, they are both foam filled...
My 1968 27 SeaMaster is also foam filled.

Unless yours was redone previously they should be foamed !

[mnwnvc]

My 1969 20 CC has hollow stringers that are factory stock.

[69Seacraft20]

Originally Posted by 69Seacraft20

If I were to remove my deck and inspect the stringers, what should I be looking for?

If they are not cracked or delaminating is it safe to assume they are fine?

Should I drill tiny (repairable) holes to check for water?

Thanks

Hmmm..Ok let's say some were foamed some were not. I have seen both opinions on this forum searching for "stringers" on 20' models. One post said stringers are popped off of a mold then glassed in hull...
My other questions still apply..
Thanks

[Bushwacker]

You have a 4-stringer Moesly hull, and I've never heard of a stringer problem in any Moesly boat. The stringers were installed about half way through the layup, as described in great detail in this article. The inner liner was then bonded to the top of the stringers, creating a relatively light but very stiff I-beam. Unless you have a large crack in the hull, I wouldn't even consider removing the deck just to inspect the stringers! You are much more likely to have a problem with a soft deck or transom than you are with the stringers!

[69Seacraft20]

Well that's good news! I have no real reason to suspect anything is wrong with it...just old boat anxiety. Transom looks and sounds rock solid even with 526lbs hanging off of it but deck will need to be redone eventually. I'm not sure if I have to pull the liner out or cut to replace deck. That link "this article" did not work.

Thanks!

[flyingfrizzle]

My 71 had the quad stringers. They didn't have foam in them but did have foam between them in the voids. The earlier 4 stringer grid stringers are far stronger than most boats and with no wood there is no rot. Only worries are if there are any cracks along the 90 degree areas where they have flexed. The only ones I seen damaged were from extreme beatings and that was on the large box stringers not the quads. If you find wet foam anywhere, get it gone look for stressed areas (you will more than likely not find any) and worry about the deck balsa and the fir in the transom if original. That is the only areas that normally have issues. Some hulls have rotted wood in the caps if lots of holes were drilled in them but the older 69-72's had super thick cap layups so may be ok there. The awesome stringer set up in these hulls are what makes them so good for rebuilds, I is one thing less to redo.

[Bushwacker]

Originally Posted by 69Seacraft20

. . . Transom looks and sounds rock solid even with 526lbs hanging off of it but deck will need to be redone eventually. I'm not sure if I have to pull the liner out or cut to replace deck. That link "this article" did not work.

Thanks!

Since that boat was designed to have about 300 lbs hanging on the transom, I hope you've moved batteries and console forward to get the CG back where it's supposed to be! Otherwise it's not balanced right, so ride and min planing speed won't match the original.

If you ever have to redo the deck, you can just cut through the top skin, scrape out the rotted wood and replace the core, which is mostly balsa core with some plywood where seat pedestals were mounted. However if you don't drill holes in it, or seal any holes with epoxy, there is no reason for the deck to ever deteriorate. My boat is all original except for the filled in transom and everything is still solid; if fact, when Don Herman filled in the transom, he said it was the driest transom he had ever seen in a boat that old! I did address two potential "transom killer" areas when I bought my 3 year old boat:

1. Frank Brown, Moesly's mechanic on his race boats who sold me the boat, said the polyester putty that was used to seal the top of transom when they dropped the cap on, was very brittle and would crack easily. Frank said that before installing a motor on a new boat, Brown & Hauptner Marine always removed the aluminum trim from around the motor cutout, routed out that joint, and caulked it with polysulfide sealant that would remain flexible and keep water out of that joint. Since I bought the boat with no motor, I did the same thing before installing the motor.

2. If you have the live well under the port seat, the plastic cup in the transom at the waterline which functions as the water inlet/outlet, is also sealed with polyester putty which will also crack and start to leak, as mine had started to do. I removed it, dried out the wood with some alcohol, treated it with Git Rot, and replaced the plastic fitting with a Pyhe plate and PVC threaded cap, all sealed with epoxy.

That link that didn't work just goes to the '69 Boating Magazine test of the Seafari that's in the literature section. You can get to it by scrolling down to bottom of page and clicking on "Classic SeaCraft Home", and then click on "Literature". Or you can PM me with an email address and I can send you a .pdf file of that article. It contains a very detailed description of the hull and stringer laminate schedule, how the stringers are installed and variations in hull thickness. I tried to attach the file to this post, but at about 2.5 MB, it's too big!

[69Seacraft20]

Thanks for all the help guys! Only paid $3500 for this boat. Nothing came with it just boat, trailer, motor and one battery. No lines, anchor, or even a fuel tank. I am getting two batteries and fuel tank for under the console soon. Battery is in original spot in transom corner right now. That should bring some weight/CG forward and I may move entire console more fwd.
The only issues I can see is the deck. It has been sitting outdoors on a trailer for almost 2 years with its t-top removed and holes was never filled also there is a small U shape crack on deck that looks similar to the heel of a boot right were you would stand at the console and there is a soft spot 6" parameter around that area so I'm guessing I should just replace deck maybe up to the cast deck. I'm also missing all 4 hatches and hinges and those holes were never filled so I need to fabricate new hatched and repair deck. Still worth it.

Thanks

[Bigshrimpin]

Make sure you inspect all the through hull fitting especially the scuppers that go down through the floor. And there's usually a block of wood b/w the deck and the bottom of the hull. This one leaked on me . . . about 8 gallons an hour

Also on my 18, I had the bronze thru hull in the front fish box come loose half way across cape cod bay (10 miles from shore) . . . I had to plow home at 8knots with the bow in the air.