next step in stringer replacement

[alloffroad]

I have the old floor out and am just about done grinding what used to be the stringers. My next step is to replace the wood on the transom. My quastion is, once I am done with the transom how do I tackle the floor. Should I lay down a layer or two or three of fresh glass before installing the stringers (which will be incased in 2 layers of mat) and if so should I put some woven roving in the mix or just mat. I will be laying mat in between the stringers. I just don't know if I need to build up the floor Where I ground down the old stringers.

 

[ondarvr]

Re: next step in stringer replacement

I assume you're using polyester resin.
If you didn't grind off any of the hull, and you shouldn't have needed to, then no you don't need to add any material to it, if you did, then replace only what you removed.

Mat has little strength when compared to roving, so multple layers of it add more weight and cost than needed.

 

[alloffroad]

Re: next step in stringer replacement

I read recently that roving is not neccesary when reinstalling stringers. The PDF file I read says that mat, 1.5 - 4 oz, is just fine for the installation of the new stringers and floor and that roving will just add cost and thickness in this case. Is this true? I have read here that roving is added for strength. Is strength needed for stringers or is a good bond to the hull more important leaving the strength to the stringer core material? I am suddenly confused. Please steer me straight.

 

[ondarvr]

Re: next step in stringer replacement

Some boats only have mat over the stringers, but not the well built ones. What you really want over them is roving, thats where you get most of the strength.

 

[BillP]

Re: next step in stringer replacement

A lot of old boats used chopper or mat and modern boats use mat and woven roven in alternate layers. Use mat on the first and woven on the second, etc. Before glassing, wipe the old glass surface down with styrene...it adds chemical link bonding to the layup and helps polyester resin stick in places you can't sand or clean well (like between the weave on woven roven).

bp