I’m in need of info concerning the building of a center box between beams 2 and 3 on a Pahi 42ft. It is not about building of the box, but that of material used.My old one needs to be rebuilt because…Continue
Started this discussion. Last reply by Lovako Jan 22, 2022.
"Hi Roger, thanks for your reply, imensly appreciated.
I understand all you say and am thankful for constructive information.
I just need to remind all that here where I am i only have ply and fibreglass to work with - no foam sandwich is available.…"
"I know from my own projects that 6mm (1/4") plywood glassed on both sides with 6oz cloth is extremely stiff and strong. I don't have any data, but would expect it to be at least as strong as 9mm ply, but is also better protected from the…"
"Chopped Strand Mat adds weight, but very little strength. Fiberglass epoxy adds an immense amount of strength, so much so that foam sandwich can be a direct replacement for plywood in many instances. There is some disagreement as to what…"
"Ian R, instead of pulling people down with any idea's they may have about their boat, sail your perfect boat out into the middle of the bay,, throw the anchor over the bow ,, however don't let go.
Lovato is asking for collective thought,…"
"Hello again Lovato:
Yes you may have built a 42ft boat, but let's face it, one boat is not the same as another.
My boat is almost 30 yrs old and looks new: how about your boat?
I have got to laugh, you even try to ban me for commenting on…"
"I agree that CSM is a poor choice, but woven fiber makes sense. However there is another option if stiffness is the goal, and that is foam sandwich. You could also use thin ply on one face in lieu of glass…"
"Hi Robert, Im all ears when people answer me in a decent way.
I built a large box hanging between beam 2 and 3 on a lip with x3 25mm stainless safety pins on each beam. My box lasted 10 years but must be rebuilt as the frame was built from soft…"
"I am also rebuilding the boxes on my Pahi 42.
Would suggest avoiding chopped strand because of poor strength to weight ratio. Skins of woven cloth on both sides is a good idea—especially for water and abrasion resistance.
"If you were meaning fibreglass cloth in epoxy, that's a different thing. Since you mentioned chopped strand that would indicate you don't know the difference between epoxy/fibreglass laminating and fibreglass laminating.
"Unlike most of the people on here I have built a Wharram as it happens!
Lorra people wanting to buy on "Wharram Builders and Friends" ; not so many building.
I shared a professional workshop with a professional fibreglass laminator…"
"Seems like a low IQ problem . . I never asked concerning the build of the box, BUT concerning the different streangths between 9mm ply, 6mm ply sheathed in one layer of fiberglass or 6mm ply sheathed in one layer glassfibre both sides.
By the way if…"
"Well exactly- you can't do a proper job with fibreglass by just layering onto thin ply. We have all seen some awful stuff done like that, it's very heavy, lumpy, and dirty and not strong at all. Not a good rep. for Wharram boats.
"Lovako - I don´t know much about the phi 42 boxes, but some suggestion on the method. You cold try what you have in mind, but I think it might end up being difficult to have a good result without having some sort of mould to place the chop…"