16 Munro Caprice - Stringers

[AMD Rules]

16ft Munro Fiberglass runabout. Making some progress on the floor & hull re-work: <br /><br />When I removed a section of the floor, I found rot as expected. What I am curious about is the gap between the stringers and the hull. It seems the stringers don't actually touch the hull at mid-span, instead they are supported by 'legs' made of fiberglass. I'll assume this was done to minimize the moisture contact with the bare wood. Was this a common manufacturing practice?<br /><br />Rotton cross member<br /><br />The stringers are not fully encapsulated in resin/fiberglass. There is a sequence of 6" fiberglass strips draped over the stringers, which then get expoxied to the hull and behave as 'legs'.<br /><br />Stringer support 'legs'<br /><br />When I replace this floor, should I use stringers made from resin soaked 3/4" marine ply standing on edge instead of dimensional lumber?<br /><br />For more photos, check out the link in my sig.<br /><br />I'm not sure what is the best approach to take from this point. I'd like to have a solid floor & transom, without spending all of my life's savings. I have removed the top deck already.

 

[Boomyal]

Re: 16 Munro Caprice - Stringers

AMD, can't imagine why the stringers would not have been anchored to the floor. It would seem to me that anchoring at a few points would increase the stress on the hull. I'd be inclined to saturate them with epoxy, glue 'em down firm and cover them with glass.<br /><br />As far a the material choice, I'd go with dimensional lumber. Whereas laminated plywood would be technically stronger, I think it would be a moot point in a 16 ft boat. The only way I would bother to use ply is if you can't find dimensional material of the proper size.

 

[AMD Rules]

Re: 16 Munro Caprice - Stringers

Thanks for the advice Boom. Do you think PT 2x6 covered in PT 3/4" ply would be the way to go then?

 

[G DANE]

Re: 16 Munro Caprice - Stringers

PT 2x6 laminated with 3/4" ply would be fine if you were building a tank. A lot less could do it, try to look at jasonj's fine silverline site.

 

[AMD Rules]

Re: 16 Munro Caprice - Stringers

lol... sorry I meant 3/4" ply FLOOR...not laminated. No tanks around here.<br />The 2x6 was for the stringers, to replace existing 2x4.

 

[G DANE]

Re: 16 Munro Caprice - Stringers

Tha way it was done, the fastening of stringers to hull would only take advantage of a fraction of the strength there is in solid 2"x4". I dont get why they made shortcuts like that. Better use something smaller and encapsulate it all the way to hull, would be a lot stronger all in all. Way more rot resistant too. Be sure to get DRY wood or ply.

 

[AMD Rules]

Re: 16 Munro Caprice - Stringers

Where's the best spot to read up on fiberglass techniques, and requirements for cloth & fillers etc? I'm eager, but somewhat naive as to the exact process and material requirements (epoxy/cloth/filler). Learning is half the fun I guess. I need to purchase supplies within a day or so, and hope to get the new floor in this coming weekend. Have a local source for fiberglass supplies and marine plywood.

 

[G DANE]

Re: 16 Munro Caprice - Stringers

Here's a good one<br />: http://www.fiberglass-repair.com/

 

[G DANE]

Re: 16 Munro Caprice - Stringers

And much better : http://www.fao.org/DOCREP/003/T0530E/T0530E11.htm#ch11.4