Fiberglass Sheathing a 1962 Carvel Hull

[Small boats rock]

Re: Fiberglass Sheathing a 1962 Carvel Hull

The biggest issue with a job like this must be the question of whether or not hull movement can be minimised enough (hopefully the question of adequate bonding is taken care of by the use of epoxy not polyester). Obviously if the moisture content of the planking is stabilised, and all locked together with splines, this will go a long way to dealing with movement... but still remaining is a traditional internal structure. Do you have anything in mind for the internal structure or is the consideration strictly limited to dealing with the planking?

[gypsie]

Re: Fiberglass Sheathing a 1962 Carvel Hull

Anyway, those of us who've put a lot of work into restoring old boats and are enjoying all the advantages of properly protected hulls and decks, don't really care about should we or shouldn't we debates that never end and I'm not going to engage in yet another pointless argument. So, Gypsie, let us know if you decide to go ahead with it, and I'll be happy to share ideas gleaned from contacts who actually know what they're talking about.

I've got a whole bunch of sanding to do no matter what - probably weeks of it. Plenty of time to get to know the hull intimately.
I'll continue to mull it over.

Sincere gratitude to all who've contributed to this thread so far.

[gypsie]

Re: Fiberglass Sheathing a 1962 Carvel Hull

This looks like the tool for the kerf.

https://www.makita.com.au/building-construction/combo-s-kits/12v-max-kits/circular-saws/hs301dsae-12v-max-mobile-circular-saw-kit

Light, battery powered. Wonder what the kerf is, would need a bigger one anyway. 15mm bore......

[Andrew Donald]

Re: Fiberglass Sheathing a 1962 Carvel Hull

I’ve got its 18v brother and kerf is only about 2mm. I wonder if you bolt two blades on? Battery might not be up to it though.

[gypsie]

Re: Fiberglass Sheathing a 1962 Carvel Hull

i checked out the 18v version, the Makita guy reckons even the 18v battery may not be up to what i need to do.
He's arguing that a light router is the way to go, and thinks the 18v machine could take 2 blades side by side.

[gypsie]

Re: Fiberglass Sheathing a 1962 Carvel Hull

How would you get a 4mm channel into a place like this? Only a router could do it I'd have thought. With an accurate baton/track nailed in.

IMG_7042.jpg

The job would be a mixture of circular saw and router.
Definitely need a router for the ends of the planks at the stem, for example. otherwise i'd be cutting across the rabbet. The rabbet will need a router too - curvy line to follow.

[gypsie]

Re: Fiberglass Sheathing a 1962 Carvel Hull

Sheathing is firmly on the cards.
I'd say i have decided - except i have yet to plunge the blade into the seams - and as Whizbang says, there's no going back then...

Rick - you mentioned a custom saw blade - I'd like to follow up on that before i buy a new saw. Make sure i'm not picking something with an exotic arbour or something.

I still have questions, and I am a bit away from complete confidence. I believe a can get the glass on well but i am concerned about areas like around the ballast. I also don't underestimate the amount of work involved in kerfing all those joins. 21 planks from the garboard, deck/sheer plank join is glued, so that's 20 joins plus the rabbet seam and all that craziness around the deadwood.

IMG_7041.jpg

There's also a lot of fairing compound to go on, to give the glass a proper landing.

In short there's a lot of work to be done - BUT i am sure that it's better to do it now, and do it thoroughly, than try and deal with hull issues year on year forever more.

[Slacko]

Re: Fiberglass Sheathing a 1962 Carvel Hull

I would put the glass on before fairing because it will need fairing after anyway.
My 2 cents worth is that the best solution for you is to buy a fibreglass boat.

[Andrew Donald]

Re: Fiberglass Sheathing a 1962 Carvel Hull

Gypsie, I’d reckon to drive a blade with 4mm kerf you’d be better off with a 7 1/4” 240v saw with one of Ricks custom blades. 4mm is pretty wide for a circ saw blade, they’re generally about 3mm and smaller in battery saws.
i also have the Makita 18v trim router and while it’s a great tool , to do as much as you want without countless trips back/forward to charger you’d be better with 240v and just hang the cord over your shoulder. Not sure but is that seam compound abrasive? Could need a few router bits, small ones don’t last real long.
its pretty easy to make sub-bases for either tool and a trailing guide pin base could be a good way to go, perhaps with two pins to keep it straight, although on convex surfaces the pins may ride up out of cut, could make then about 1/2” long?

[RFNK]

Re: Fiberglass Sheathing a 1962 Carvel Hull

Yes, a trimmer/router where the saw won't fit, and chisel where the trimmer won't fit. When I was going to respline the Twister, I was going to use a 7 1/4" saw. The splining blade needs to be custom-made. I have a friend who did his boat, many years ago, and he'll know what size and angle the blade will need to be. In theory, you could do the tapered slot by doing two runs with the saw up the other way on a relocated batten - if you see what I mean. But getting a blade made should be a lot simpler with less room for error.

Any good saw shop should be able to make the blade. We have one in Newcastle but there'd be some in Sydney. I suggest that I ask the friend about size and angle and you then get some quotes. I'll get a quote from the guys in Newcastle too. The shop is Saw City in Cardiff. Nice people and really knowledgeable.

[RFNK]

Re: Fiberglass Sheathing a 1962 Carvel Hull

By the way, I think the tapered groove/slot/kerf is important. I can't really see why Gougeons would recommend a straight slot. I think the spline would just push all the glue out unless i t was a really loose fit. A loose fit is okay with epoxy, of course, but I'd still be concerned about voids and dry areas.

I'd put the splines in with polyurethane glue, like Purbond. It's just as strong as epoxy, sands more easily, allows a jam fit and likes moisture. So, if the planking is still a bit moist when you do the splining, the poly glue will still bind, whereas epoxy won't. The planking will need to be fairly dry so that there won't be much more shrinking but the glue will work well if there's still a bit of moisture on the edges in the seams.

[gypsie]

Re: Fiberglass Sheathing a 1962 Carvel Hull

Gougeon recommend a tapered spline. The objective perhaps is to have a gap at the back filled with glue that's been forced deep into the cut by the taper.
In your thinking Rick - you saying a tapered slot with a rectangular cross section spline? Or tapered spline too?

I'm with you Andrew - 240v for sure.

T

[gypsie]

Re: Fiberglass Sheathing a 1962 Carvel Hull

A 185mm saw has a cutting depth of 63.5mm (Makita 5007). If i took 40mm off the radius that gives me 105mm blade.
I could fit a 105mm blade to a 185mm saw and not run the risk of plunging the saw through the planks - or through a frame. It also gives me a lower profile saw to manage - handling a saw that's been tilted up is a bit more fraught than one fully flat.

There's no custom saw place near me that i can see. But there is Henry brothers in North Sydney.
Thinking rip saw blade, 105mm diameter, that'd be about 20 teeth. 4.5mm kerf.

[Rumars]

Re: Fiberglass Sheathing a 1962 Carvel Hull

Use a biscuit joiner to cut the slots. 4mm blades are commonly available and you have a fine depth adjustment.

[wizbang 13]

Re: Fiberglass Sheathing a 1962 Carvel Hull

I don't think the boat needs splining, just kerfing and epoxy filling.
Splining the topsides gives the advantage of avoiiding "print through", when the hard epoxy shows up in the sun through the softer wood.
But below the waterline, in all those hard to reach areas? Trust the epoxy or go home.
For epoxy filled kerfs, the job will use much more epoxy, duh, but the time saved would more than offset that cost. It always does.
The accuracy of the kerfs is uninportant, where did this 4mm number come from?
Just cut away the wood fouled with old pitch, old motor oil, old linseed puttyu, old red lead, old anti foul, ...like that, cut it away.
A 4 inch cordless skilsaw...one can clean those seams faster than 3 batteries can charge...
Meanwhile, splining the topside seams is so much easier anyway, if you insist.
bruce