newbie lookin for help

hello, new guy here, looking for some answers from those that been there.
i am rebuilding a 1974 osborn 15' 9" boat have all peices cut and ready to reassemble, transom stringers and deck have ???S about cloth and mat weights, i have some material not sure if its will work, i have 15 yard of 1708 biaxial, and 25 yard of 1.5 oz mat let me know if this will work. i will be using polyester resin to wet out all.
1. transom is 2 ply 3/4in marine plywood, i know i have to tab it in. is 8 inch tab ok? and how many ply of material do i use.
2. stringers are overbuilt 2x doug fir, will the 1708 work or will i need to get woven roving.
3. decks will be 3/4 in marine plywood coated underside w/ 1 layer of 1.5oz mat. approx how much resin will i need to complete.
4. is there an around the house sub for areosil, trying to keep expenses down think with all the fileting that could get to be expensive
5. changing floorplan from dual side console to center console will run all cables and wires thru a cover on deck from a carolina skiff. any issues i need to be aware of?
thanks in advance for all the help tips and advice
dennis

 

Hi Dennis,

I'm only going to address your questions that I have experience with.

2 Regarding your stringers. Last year I built a pair of engine stringers for my Silverton with 1708 biaxle mat. The mat went over a foam core with 2" laminated ply inserts where the mounts attach. I used 4 layers generally and 6 where the mounts were located. This gave me a laminate thickness consistent with Dave Gerrs scantling rule from his book "The Elements of boat Strength". You'll get differing opinions regarding the use of 1708 mat but it has worked well for me. I installed a small block Ford with a Velvet Drive and a v-drive, total gear weight over 1000 lbs. No issues. Check Gerrs book for laminate thickness, I think in your case 2-3 layers would be sufficient. 1708 mat drapes and tucks pretty nicely, you should be pleased with the results. You'll probably use quite a bit more epoxy than you think you will, it really soaks it up.

3. The decks. I'd use just straight epoxy. That mat isn't going to produce any strength but it will add weight. I'd just give the deck/floor/sole or what ever you want to call it three good coats of epoxy resin on all six sides, then paint or varnish. Do a good job and you should be fine.

As for the rest I'll defer to others with experience building transoms...

Good luck and welcome,

MIA

 

The use of mat is a waste of resin if using epoxy. There is no difference in opinion among knowledgeable epoxy users in regard to mat and epoxy use. Any one that thinks it is okay to use mat with epoxy does not understand what function mat has within a polyester or vinylester laminate. If you want to use 3 times the resin you need, then put some mat in the laminate.

 

thanks

i will be using nonwaxed polyester resin to wet it at in

 

With polyester or vinylester, you must use mat, so you are good to go osborn159. Seal the wooden parts well or you will be doing this again.

 

need help

thanks hunter25, anyone know where to find lepage pl9000 adhesive in the us, their website lists canadian outlets, cant seem to find an outlet this side of the border
again thanks for all the help and advice