Stringer resoration on a 20 sf

71kidcasper · #1 07-29-2006, 02:00 AM

I have a 71/72 20 sf that I am starting to restore. I have been contemplating my options when it comes to repairing the stringers. I have seen several different ways to repair them on this site. My boat has the four stringers which are about four inches wide. I have an idea that I would love some input on. I have been thinking about filling up the space between the stringers on the port and starboard sides with 4lb. expanding polyurethane foam and then glassing the new larger stringer. Has anyone else already tried this? Basically I want it to look like the stringers in the later built boats 74 and later.

Bigshrimpin · #2 07-29-2006, 02:16 AM

What's wrong with them the way they are now?

71kidcasper · #3 07-29-2006, 03:32 PM

The stringers that are in the boat have some cracks in them and I thought that the lager ones would make the hull alot stiffer.

Yamtt125 · #4 07-29-2006, 04:40 PM

I'd inspect the stringers some more...did you already take up the floor, and you have a good look at them?
I'm redoing my 71 20' sf and i'm about to put the new wood in the transom. Next I plan on replacing the floor and making new storage boxes for the back of the boat.
My strings look like the are in pretty decent shape, so I plan on just adding more glass to them to beef them up a bit, and make a tank coffin under the floor between the middle stringers.
-Andrew

71kidcasper · #5 07-29-2006, 04:53 PM

yamtt125 yes, I already have the deck and transom cut out. I'm doing the transom from the outside like HERMCO recommends. The stringers are not in terrible shape they have some cracks and they can certainly be repaired. I was just thinking of a way to stiffen up the hull without rebuilding the stringer system like Trayder did. I think he did an excellent job I'm just trying to avoid all that work.

Yamtt125 · #6 07-29-2006, 05:36 PM

I am also considering making a grid systemfor the new floor to sit on. I think that would be enough to strengthen the hull up. The boat lasted for 35 yrs the way it is now, so i think any improvment would help alot. Happy building
-andrew

Bigshrimpin · #7 07-29-2006, 06:00 PM

If you want to save time and money in materials . . . repair the cracks and weak spots. I glassed down 2 layers of 3/4" MDO on top of the stringers to raise the floor and covered them in 2 layers of heavy mat.

71kidcasper · #8 07-29-2006, 06:56 PM

Bigshrimpin, looks like your doing agreat job with your stringer mods. Can you tell me roughly where you placed your fuel tank and how many gallons it is? My 20sf was an I/O that I am changing to an outboard so the original tank was above deck.

Lenny · #9 07-29-2006, 07:36 PM

What about the inside of the stringers?? My 69 appears to have nothing inside of them? I cut them away from the transom and it appears that a piece of wood is at the very top on the inside much like a piece of strapping? I have a couple fractures that need to be fixed up but not knowing what is supposed to be inside is driving me nutz

Bigshrimpin like what you have done am curious to the tank dimensions I also plan on dropping a tank in the floor like that is that where she will sit? I was thinking more forward on my I/O model ??

Bigshrimpin · #10 07-30-2006, 02:53 AM

My stringers were the same way . . . empty shells. Ocean Master has the same type of stringers and those boats are solid as a rock. If you want to add floatation - drill some holes and fill the stringers with foam or you could add 4lb pour foam floatation around the stringer system.

I got that tank from Marine Connection Liquidators for $175. It's a 52 gallon surplus tank from Maverick boats. You'll need to raise the floor 2" to use that same tank.

This picture was after a good rain and before I added the limber holes for drainage.