New Stringers and Floor

[raymondf]

Hello to all,

I am new to boating and just purchased a 15 foot fiberglass runabout. It needs all the wood replaced so I ripped out the floor and stringers. What type of wood should be used for the stringers? How thick of a floor should be put in? I was also wondering if i should put expandable foam between the stringers and flush it up with the top of the stringers for a more stable floor? any advice would be appreciate it.

 

[deejaycee_2000]

Re: New Stringers and Floor

Why don't you get aluminium stringers? Floor thickness about 20mm ...

 

[Chinewalker]

Re: New Stringers and Floor

I used plywood for the stringers and floor in my restorations. AB or AC will work fine if encapsulated in epoxy. For the stringers I laminated two layers of 1/2-inch to get a full 1-inch stringer thickness, staggering the butt joints every four feet or so, so that I could get 12 and 16-foot stringers out of an 8-foot sheet of plywood.

Bottom line is that for the most part, most anything you use and do will be better and with more attention to detail than it ever was originally.

I used 2-part foam for flotation and rigidity in my boats. If memory serves, it was 4-lb. foam.

- Scott

 

[Chris1956]

Re: New Stringers and Floor

Ray, I would recommend dry pressure treated solid lumber for the stringers and frames. Use 2X 4 or 2X6 lumber (whatever the original was), and use cloth and resin to glass them to the hull. Fill the voids between the srtingers with the 2-part foam mix and let it harden. Slice off the excess. Use 1/2" dry pressure treated plywood for the floor. Saturate some 2" wide cloth strips with resin and lay 2+ layers on top of the stringers. Now, using SS screws, screw the precut plywood floor to the stringers. Now cover the plywood with at least one layer of saturated cloth, and let it harden. You can use all polyesther resin for your repairs. Make sure you sand all areas you plan to resin down to a clean, sound surface, and after sanding, wipe everything with acetone, prior to glassing it.

 

[Mr Hands]

Re: New Stringers and Floor

Hello to all,

I am new to boating and just purchased a 15 foot fiberglass runabout. It needs all the wood replaced so I ripped out the floor and stringers. What type of wood should be used for the stringers? How thick of a floor should be put in? I was also wondering if i should put expandable foam between the stringers and flush it up with the top of the stringers for a more stable floor? any advice would be appreciate it.

On my 1970 18 foot fiberglas hull, I used 2x4s & 2x6s for stringers, epoxy resin & fiberglass mat, along with 2 part foam with a bunch of 2 litre pop bottles mixed in (they do float in the foam so do 2 pours or tape them down first). For the deck I used exterior 3/4 plywood saturated with epoxy and a layer of fiberglass cloth over mat. I'm sure I could have gotten away with 1/2" with the epoxy & glass.
Aluminum stringers sound like a good idea, but I'm not sure how I would have contoured them to fit the curve of the hull.

What I would have done differently (had I only known about this site when I embarked on this journey) I would have made sure there was a drainage channel on either side of the center board. This was not something incorpoarted into the original hull design, so I did not include it in my restoration. Oh well, too late now!

Good luck to you - I'm sure it will be much better than new when you are done!!

 

[raymondf]

Re: New Stringers and Floor

Hello to all,

I am new to boating and just purchased a 15 foot fiberglass runabout. It needs all the wood replaced so I ripped out the floor and stringers. What type of wood should be used for the stringers? How thick of a floor should be put in? I was also wondering if i should put expandable foam between the stringers and flush it up with the top of the stringers for a more stable floor? any advice would be appreciate it.

On my 1970 18 foot fiberglas hull, I used 2x4s & 2x6s for stringers, epoxy resin & fiberglass mat, along with 2 part foam with a bunch of 2 litre pop bottles mixed in (they do float in the foam so do 2 pours or tape them down first). For the deck I used exterior 3/4 plywood saturated with epoxy and a layer of fiberglass cloth over mat. I'm sure I could have gotten away with 1/2" with the epoxy & glass.
Aluminum stringers sound like a good idea, but I'm not sure how I would have contoured them to fit the curve of the hull.

What I would have done differently (had I only known about this site when I embarked on this journey) I would have made sure there was a drainage channel on either side of the center board. This was not something incorpoarted into the original hull design, so I did not include it in my restoration. Oh well, too late now!

Good luck to you - I'm sure it will be much better than new when you are done!!

[/quoteI want to thamk everyone who replyed. I will be starting on this this weekend and will keep everyone updated on it. I can not wait to get this on the water.

 

[sport15]

Re: New Stringers and Floor

With a 15' run about hull unless you want to drop crab pots or full beer kegs on it there is not really a need to go a full 1 inch for a deck, unless you want to make the boat heavy.. 1/2 inch is fine and 5/8 is plenty especially if glass is to be added to the outer surface and you are putting stingers underneith. 2 stringers means 5/8 minimum, 3 stringers then we're back to 1/2 inch. Put foam in there and the foam takes the deck load, so 1/2 is the winner... For a light boat like you have 2x is over kill, 3/4-1" is fine. If you plan to glass it all together than 3/4 is plenty.

If you are going to bolt on a 150 black max, that's a differant story!

If your intended use is casual fishing/water ratting with low horse power put it all back together "light" but strong. 1 -2" Closed cell foam board shaped to fit the hull that is epoxied in place capped with 1/2-5/8 ply strips then covered with directional weave cloth such as E or S glass or Biaxial will make for a light, stiff strong composite. The ply will provide a place for fasteners when screwing down the deck and will act as a stiffener for the stringer top. The strength in the deck/stringer joint comes from the epoxy goo that you mix to hold it all down. Don't forget that the underside of the deck gets 3 coats of epoxy to keep moisture out. The deck edges can be filleted and taped to the hull sides then the whole show faired and covered with cloth.

Just another point of view... Dave