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I'm not sure what the proper name is for the boat I have - it's a 66 cuddy cabin approx. 17 at the waterline and 20 loa.

I've got the aft floor panel up to try the Ward Strong "hull jacking" method (thank you, Ward!) to correct about 20mm of hog.

My sub floor structure includes two sister keelsons on each side, one and two feet outboard of the keel. And then I've got a piece of wood that looks just like a rib only it runs fore & aft attached to the ribs just below the floor line.

On top of all that I have 1x2s running side to side spaced every twelve inches. The floor is actually screwed down to these strips. The strips are screwed down to the inner sister keelsons. But the 1x2s just sit on top of the outermost stringer that's attached to the ribs at the floor line. They are not attached and there don't seem to be any screw holes indicating they ever were.

Now I know why I get a loud banging sound running in rough water - the floor is slamming down on that stringer. I'd just add screws but the stringer is flush to the ribs it's attached to and they continually curve outward as you move forward. So those flooring cross-strips actually sit on the top edge of the stringer, not flush with a surface.

Did somebody run out of screws while working on this boat? Or forget to bevel that stringer? I can't believe the floor is just supposed to lay there unsecured. The floor panels were recovered in Nautolex several years ago but I think they are still the original boards and original sub floor structure.

Any suggestions on how best to secure the outboard ends of those flooring attach strips?

George

Welcome aboard!

What kind of boat? What company made it and where? What model? This may be important to help answer your question.

Boats by Thompson et.al. are typically measured for length at the centerline from tip of bow to end of transom, perpindicular to the transom. Measure at the level of the deck. Also measure around the gunwale from tip of bow to edge of transom. Measure at the rub rail.

Is there a hull ID stamped into the wood of the transom? Is there a serial number plate? Is there a metal Outboard Boating Club (OBC) metal plate with listings for maximum HP and weight capacity?

If we know what you have, it will be easier to help you.

Andreas

Andreas, it's a 1966 Thompson Bros Peshtigo Wisconsin wood lapstrake boat with a cuddy cabin, 20 ft tip to tail and 22 ft 7 in along the gunwhale bought from Thompson dealer Airmarine Motors of Chicago. I think the hull data plate is somewhere in the paperwork back home. The OBC plate is 180 HP, 11 people, 4,000 lbs.

George

It's probably an Off Shore Cruiser which in 1966 should have centerline length of 20'-1" and gunwale length of 21'-9"

On the 1965 Thomspon Bros. 17'-11" Sea Lancer I restored a few years ago, the floor riser (thing that runs under the floor along the edge of the floor boards) was screwed to the ribs. The floor riser is on top of the ribs. The floor boards were in turn screwed to the floor riser. I suppose they did it the same way in 1966 and on a different model.

Andreas

Tape measure musta slipped when I was doing the gunwhale...

I've got that setup you mentioned. The riser running along the edge of the floorboards is screwed to the ribs. But instead of the floor sitting directly on it, I've got 1x2s that run crosswise. The floor screws to them. They are attached to the first sister keelson but not the riser. And I can't find any holes (in either the riser or the 1x2s that would indicate they ever were.

Do you think somebody added the 1x2s to simplify screwing down a new floor?

George

I have never seen up close and personal the bilge of a Thompson Bros. boat bigger than 18 ft. So maybe those 1 x 2's are original. I just don't know. If original, they would almost certainly be white oak like the other floor framing and stringers...

Andreas

George:
I have an early 1967 Peshtigo 20' Offshore camper which is similar to yours, hull wise except for the cuddy. My floor supports are the same as yours, running span wise with no screws on the outboard ends. Perhaps the builders didn't want to transfer the weight of the floors onto the ribs using fasteners in order for the planking/ribs to work without any hard spots. I thinking I'll fastenen mine with silicon Bronze screws when I go back together next spring. Unless Andreas or someone else advises me not to.
Don

Glad you let us know that your boat too did not have the floor fastened to the floor risers.

I don't know what to recommend.

Andreas

Don, I guess the only reason I never noticed the floor unfastened before was because the boat originally had twin Johnson 80s and the dealer installed slim 20 gallon fuel tanks port and starboard. The top of the straps holding the tanks were screwed to the ribs and the bottom to the floor. That held the floor down to the stringer without fastening.

George

I noticed that when I walked about in my boat (I have an OMC I/O), the aft flooring was very spring in spots along the sides of the boat. I thought it was just a problem with the old original flooring. When I remove the flooring and galley, in prep to turning the boat over for bottom work, I discovered some of the floor beams were warped and not contacting the longitudinal stringer along the chine. This caused the springy sensation in the floor. In addition, the top of the stringer is not mitered for the angle of the floor beams contacting them. This leads me to believe the builders, for whatever reason, never intended for the beams to be mechanically fastened to the outboard stringer.
Don