Covering a carvel planked hull with glass cloth

[Pelle]

I know I'm risking my neck, but here we go.....
The hull in my boat is fairly good. Some rot at the ends, but all in all: not bad. The seams however is brittle and coming loose here and there. My plan for my boat is to convert it into a passagemaker. Our ambition is to sail out for a few years to warmer climates. Just completing replacing all deckbeams, carlins, bulkheads, (doubled up) frametops and quite a bit of the beam carrier, I'm thinking of what to do with the hull. Beeing a novice, I've replaced some of the planking (while the decking was off) with new planks made up by strip planking. (Here I can sense people getting offended out there). I've also added reinforcements on the innside of the hull at certain places with offcuts from plywood and planking laminated together. For me the all important issue is strength and I feel probably as strongly for that as George Buehler does, and he's not liked by everyone at this forum. Well, my decking is one 15mm plywood and one 12mm plywood which will receive 5mm oregon pine for deck planks and oak for covering planks/king plank embedded in epoxy. I've also used epoxy fillet and 3 layers of 80mm woven glass tape to further strengthen the intersections between hull/deck, carlin/deck and beams/deck. Quite a big job, but I thin it'll pay off. That was the underlaying information.
I want to take my boat up on the hard and remove all the goo in the seams milling the open. I will dry them out locally with the aim of a heat gun, apply epoxy and then carefully tap in the wooden wedges put in thickened epoxy. Then I want to plane the wedges flush with the hull, fill imperfections, sand the whole thing and seal it off with 2 layers of glass cloth set in epoxy. Afterwards I want to saturate the inside with terpentine, raw linseed oil and some anti parasit.

My theory is: Using the heatgun will only dry out the portion of the wood to be glued. The rest of the plank will keep its shape, not beeing "overdried". The application of linseed oil will keep the planking dimensionally stable without the fear of drying out over a short period. Obviously the sheating will keep teredo worms and other nasty creatures on the outside. Since my deck is 100% waterproof (and ditto the aluminium superstructure), no fear of fresh water in the bilges. I'm to focus on air circulation and will be using the boat as a liveboard as from spring, so I'll be able to keep a close watch to things. Well, your comments will be appreciated, but no low blows, I've seen some of your comments to "a wooden boat novice", so let's keep the tone in a sivilized manner, OK ??
Oh! the epoxy I'm using is something called Aeropoxy. It is a bit more "stretchy" than west-system epoxy. In other words, it can take some tension without cracking with a snap. I also plan to stiffen the intersection between frames and hull planking on the inside (prior to the linseed oil thing)

[WFK]

:rolleyes:

[rbgarr]

You might benefit by reading 'Covering Wooden Boats with Fiberglass' by Allan Vaitses, if you haven't done so already.

[Gary Bergman]

:rolleyes: :eek: :rolleyes:

[JimD]

Pelle, WB mag ran an article a couple or three issues back on glassing planked boats. I don't have it handy but as I recall it mainly said first replace any rotten wood, then add enough fiberglass to ensure the planks are immobilized, or are imobilized in some other way. The early attempts at glassing planked boats failed because the planks worked against each other and soon sheared the glass cloth. I don't recall what it said about the wet/dry issue, which seems to me to be the crux, but I haven't any experience at that. Hopefully others can help.
jimd

[David Greenup]

there got to be some way for yer moisture to move outof yer wood if the wood got moisture itl want to get out somewhere maybe in the middle of yer passage when its turned yer wood to mush cause it couldnt get past yer goop (epoxy is fer wood with 12% or less moisture). good luck

dave dido :eek:

[imported_Conrad]

If you like George B's ideas (and I agree with some) why not go with plywood strips, roofing mastic, and a pneumatic stapler instead of the glass. It will be cheaper, probably work better for a planked hull, and you can rip it off later if you change your mind. It will save you the effort of cleaning/splining the seams, which is considerable.

I'm open to alternative methods, as well as quick and dirty. We're just finishing up sheathing the bottom of my own boat, so I have experience. It seems to me you've got to go one way or the other, either quick and cheap, or do it right, but there's little to be gained by mixing your strategies. If you aren't going to let the boat dry completely (say for a year) and design in what ever is needed to assure it stays dry, I feel what you propose will fail after having cost you a lot of time and money. For example, you can't saturate wet wood with either oil or preservatives, and after you glass, (if heavy enough to have a chance of working) your hull will dry from the inside, shrinking the planks and seperating the glass. It has got to be dry to start. With the wood/tar overlay, it won't matter, moisture can go all the way through.

Here's a link that talks about what we've done so far, and have planned for the future.

http://media5.hypernet.com/cgi-bin/UBB/ultimatebb.cgi?ubb=get_topic&f=1&t=005931&p=

[ion barnes]

I have concerns about the glas/wood interface and have been skeptical of Allan Vaitses' work on those old wooden hulls. I believe that he did that work along time ago when glass was the new miricle on the block and wonder what became of those projects. Its only my opion, but really, the only thing holding the glass hull skin to the wood hull are the multitude of bronze staples. I would be more inclined towards epoxy and wood vinears.

[Ian G Wright]

Oh God,,,,,,,,,,,

IanW :( :confused: :mad: :eek:

[Scott Rosen]

If you are going to spline the seams, and you do it properly, then there is absolutely no need for fiberlass. If you are seriously concerned about worms, then the best method is copper sheeting. If that's not your cup of tea, then there is a product called SteelFlex (or something like that) which is designed to go over the hull with epoxy.

As for your other repairs, I would be very cautious about mixing methods in a boat that will be used as a real passagemaker. I'd want a professional's opinion about the proposed work before I started it, and I'd want a good surveyor to give the boat a thorough going over before I set sail.

Gentle enough for ya?

[Pelle]

Hi!
Thanks for the suggestions/comments so far. I'll order Allan Vaitses book today to have a look at what he's done.
When it comes to the use of raw linseed oil: Won't it allow the wood to breathe ? My thought was to make the
outside of the hull watertight, and then gradually replace the water content in the wood with linseed oil over a time.
I also belive that at earlier times when people used glass and polyester, the polyester would come loose over large
areas and thereby making the glass come off in flakes. Some polyester covered wooden decks here in Norway has
also severely rotted at most cases. However, when it comes to epoxy, this glue sticks to the wood unlike polyester.
Conrad:
I've been thinking of using the GB consept with plywood and roof mastic. Some boat worker I talked to here in
Norway some months ago said it was the only way to go cause of the mastics flexing ability. What do you think, Conrad,
Could I use glass epoxy on the outside of the plywood ?
Obviously, although my wife is also keen on our project, I really want to take off southwards. That's why the focus is on
strength and my own (lack of) abilities and not so much beeing true to the boatbuilding tradition (lack of money and time
, sorry ). I want a hull that's strong and sound.
Conrad, what do you mean that the moisture will go straight through. Will not the gluelines in the plywood act as a
barrier (at least for the first years) and so will the roof mastic ??
Can I not risk drying out the wood inside out unless repeatedly applying raw linseed oil ?
I had a look at the link you provided. Most interesting. How is things going ? What is an 37' egg express cruiser anyway?
Details, homepage ??
Scott: The copper sheating was removed by my just a months after I bought the boat. Over here we've had some
terrible cases where the underlaying wood has been nutricious and soft enough to grow potatoes in.
I will have my boat voluntarily surveyed before I take off. Thanks for beeing so gentle Scott, I hardly had any sleep
last night fearing you would come down hard on me.. smile.gif
Please, all of you (but preferably those with first-hand experience) share your views and suggestions on how to
make my hull a strong one without me having to use the next few years to accomplish this.
Although not updated in a while, my homepage is at http://home.world-online.no/~dreggen or get the link at
my profile.

Pelle

[ken mcclure]

Pelle, the LAST thing this group could be called is "civilized" :D

I am in no means an expert, but just from my readings and learning I can see a number of problems.

Some, and almost definitely not all, issues you may want to look into (and hopefully some of the more experienced can chip in) include:

1) How will the type of wood from which your hull is constructed be able to deal with the different water conditions you will encounter? (worms, etc.) You should accept it as an inevitability that somewhere, sometime your sheathing will be penetrated and permit water and organisms to reach the hull.

2) What will your sheathing system do to the longer-term maintainability of the hull, and to the short-term repairability? If your hull is carvel-planked now, repairs should be reasonably straightforward.

3) Is there an easier way (than sheathing) to achieve the level of water-tightness you need? Carvel-planked boats have plied the waters of the world for many years - most without serious leakage problems.

I shudder to see Cleek and Fleming reply to this one ... it's a bit like seeing a traffic accident about to happen. You know - you really don't want to see it but you just can't look away.

[Bob Adams]

Scott, I think you are refering to "Sea Flex", a sheathing method that has saved a few old boats when there was no other way. This is a glass mat, bonded to the hull with 5200 and mechanical fastenings then saturated in epoxy. In general, sheathing a carvel hull is the last major project before the burn pile.

[JimD]

Originally posted by Conrad S.:
[QB]It seems to me you've got to go one way or the other...but there's little to be gained by mixing your strategies. If you aren't going to let the boat dry completely (say for a year) and design in what ever is needed to assure it stays dry, I feel what you propose will...(fail)

[QB]That was how i was thinking also, but didn't want to be too much of an armchair expert on something i haven't done myself. I agree either make it a dry fiberglassed boat or a wet planked boat. Trying to mix the two sounds like a bad idea. I have edited Conrad's entry only in the interests of brevity so hope i haven't distorted the meaning. Also, there are crucial diffences between polyester and epoxy, especially resistance to water penetration, so far as i have learned. Some people seem to get preoccupied with a $ difference, and overlook the different characteristics between polyester resin and epoxy.
jimd

[Paul Scheuer]

Is there a weight calculation in this equation ? Aside from the longevity factors, it sounds like a lot of "stuff" being added. You may not have room for cruising essentials (see USS Constitution thread). ;)

[Greg H]

Where is CLEEK?

[rbgarr]

From the Introduction to my 1981 copy of Vaitses book :

'In 15 years, no job that has been done with strict adherence to the precepts of this system has failed.'

I don't think fiberglass was considered a 'miracle' product even in 1966.

[imported_Conrad]

The more I think about this, and am able to understand your posts, the more I think you should just go with the ply/mastic solution. You could put some light cloth and epoxy over the ply if you want to for worm protection, although my understanding is it's unneccessary, since worms won't go past the glue lines in the ply, let alone the tar/mastic used as adhesive. In addition to the staples, why not shoot in some galvanized nails on a regular basis, especially around the perimeter. In my opinion if you're going to glass, the entire hull should first be repaired/restored to a condition where the glass really isn't needed, or be prepared to kiss the whole thing goodbye in only a few years.

The affect of the wood overlay on my hull has been significant to say the least. Where before, even after refastening, etc., the stands supporting it would push up into the hull by almost two inches before lifting the hull, now the change is almost immeadiate. I doubt it flexes more than a quarter inch, and we still have additional bulkheads, etc to go.

My hull is about 37'X 13'. The weight of the overlay, including ply, epoxy, nails, fabric, and copper/epoxy bottom is about 500lbs. The additional flotation gained is about 600lbs., plus the loss of water saturation in the hull at about 200lbs means the boat will actually end up floating about 1/4" higher with a net weight gain of perhaps 300lbs on a displacement of 20k. Glass, when strong enough to do the job, will weigh a lot more and cost significantly more, even if done with polyester.

http://www.imagestation.com/picture/sraid43/pf4a9c89c5cab8951882a956dffbc38fc/fce75d92.jpg

[ 12-22-2002, 04:52 PM: Message edited by: Conrad S. ]

[Adam C]

Why does this sound like a band aid solution? I am going through this dilemma with my boat after the garboard incident, and my wife wanted to have the bottom glassed.

It just feels half assed and poorly thought out. We've decided to have the bottom rebuilt by a professional shipyard, and probably three times the cost of glassing. But she'll be tight, safe, seaworthy, and we will trust it. The boat sailed perfectly with a wood bottom for fifty years...why should I change it?

Especially if you are going to do serious offshore cruisng...you don't want half assed. Do it right. Spend the money. Or buy another boat.

[Keith Wilson]

The conventional wisdom, FWIW, is that putting fiberglass on a piece of wood large enough to move around with changes in the amount of moisture (i.e. anything other than plywood or strip planking) is a Very Bad Idea.

I have no personal experience with this, but I have read of several very sucessful projects where an old carvel-planked hull was covered with a cold-molded skin. The general procedure is to let the hull dry out, then epoxy several layers of veneer to the outside, sometimes followed by glass cloth, effectively using the hull as a mold for the new skin. You could use several layers of thin plywood as well. Probably the best-known example is Tim and Pauline Carr's "Curlew", which was done around ten years ago, and which they sail to places I'd really rather not go in a small boat.

This is somewhat more complex than just wedging the seams and glassing the outside, although as I understand it you can leave the seams alone. The layers of sheathing need to be spiled to shape, and there is all the hassle of cold-molding - lots of staples, lots of goop - but according to what I've heard, it works quite well if done carefully, and should produce a spectacularly strong hull. Weight is not an issue, since the additional bouyancy of the sheathing more than compensates for its weight.

[ 12-23-2002, 01:58 PM: Message edited by: Keith Wilson ]

[Scott Rosen]

Bob, you're right. It's called C-Flex. Here's a link. The resin itself is different from epoxy, and has been used as a bottom coating to resist worm damage. http://www.glen-l.com/supplies/cflex.html

[john welsford]

I have seen several old carvel boats glassed over , two followed Vaitses book pretty closely and I for one would not like to go far out of my depth in either now that they are a few years on, I have also helped redo an old and very sick fishing boat with chicken mesh and cement, she's pretty ok after close to 20 more years, but the boats that I have had dealings with that have survived the best ( apart from the serious and comprehensive carvel rebuild including frames stem and transom) have been the ones that were dried, splined, rot routered out and graving pieces fitted, faired off then three layers of 6mm veneer glued and stapled on . 10 OZ glass in epoxy over that.

The 100 plus years old and sick Curlew more than a decade after this treatment is as dry as a bone and still racking up the miles deep in the wild blue stuff. I only managed to visit the Carrs shed twice, but have seen the process used on other boats and the transformation is amazing even if some traditional shipwrights dont like it.
It works!
JohnW


Originally posted by Pelle:
I know I'm risking my neck, but here we go.....
The hull in my boat is fairly good. Some rot at the ends, but all in all: not bad. The seams however is brittle and coming loose here and there. My plan for my boat is to convert it into a passagemaker. Our ambition is to sail out for a few years to warmer climates. Just completing replacing all deckbeams, carlins, bulkheads, (doubled up) frametops and quite a bit of the beam carrier, I'm thinking of what to do with the hull. Beeing a novice, I've replaced some of the planking (while the decking was off) with new planks made up by strip planking. (Here I can sense people getting offended out there). I've also added reinforcements on the innside of the hull at certain places with offcuts from plywood and planking laminated together. For me the all important issue is strength and I feel probably as strongly for that as George Buehler does, and he's not liked by everyone at this forum. Well, my decking is one 15mm plywood and one 12mm plywood which will receive 5mm oregon pine for deck planks and oak for covering planks/king plank embedded in epoxy. I've also used epoxy fillet and 3 layers of 80mm woven glass tape to further strengthen the intersections between hull/deck, carlin/deck and beams/deck. Quite a big job, but I thin it'll pay off. That was the underlaying information.
I want to take my boat up on the hard and remove all the goo in the seams milling the open. I will dry them out locally with the aim of a heat gun, apply epoxy and then carefully tap in the wooden wedges put in thickened epoxy. Then I want to plane the wedges flush with the hull, fill imperfections, sand the whole thing and seal it off with 2 layers of glass cloth set in epoxy. Afterwards I want to saturate the inside with terpentine, raw linseed oil and some anti parasit.

My theory is: Using the heatgun will only dry out the portion of the wood to be glued. The rest of the plank will keep its shape, not beeing "overdried". The application of linseed oil will keep the planking dimensionally stable without the fear of drying out over a short period. Obviously the sheating will keep teredo worms and other nasty creatures on the outside. Since my deck is 100% waterproof (and ditto the aluminium superstructure), no fear of fresh water in the bilges. I'm to focus on air circulation and will be using the boat as a liveboard as from spring, so I'll be able to keep a close watch to things. Well, your comments will be appreciated, but no low blows, I've seen some of your comments to "a wooden boat novice", so let's keep the tone in a sivilized manner, OK ??
Oh! the epoxy I'm using is something called Aeropoxy. It is a bit more "stretchy" than west-system epoxy. In other words, it can take some tension without cracking with a snap. I also plan to stiffen the intersection between frames and hull planking on the inside (prior to the linseed oil thing)

[Pelle]

Hi all!
Thanks for suggestions and comments. Sure, I won't be adding glass cloth on my boat. It's what you all say: it'll get too much movement ripping it apart. The ply/mastic solution works, according to George Buehler who I just had contact with on the internet. But , as he (and some of you here) claims: If it's OK (the hull), why bother ???
The cold molding of veneer with epoxy should be a "bullet proof", but tedious work. Thank's for the pic, Conrad.
Well, to sum up: I think I'll use the ply/mastic on my transom at next haul. Then this will be my laboratory for the next years, and maybe I'll go along doing this to the whole hull.

I hereby declare this discussion for ended....
Thanks

Pelle

[Mike Field]

.
Except for this --


Originally posted by Pelle:
Thanks for beeing so gentle Scott, I hardly had any sleep
last night fearing you would come down hard on me.. :D :D :D

What it is to be notorious....
.

[Thaddeus J. Van Gilder]

AhHHHH!

but seriously.. the best glassing jobs I have seen have been done like so...

C-Flex laid over 5200 at right angles to the rabbet, right up to the sheer.

Then they were glassed over that mess.

with the 5200, there is less chance of delamination related to plank expansion and beings that water is required to cure 5200, you don't have to go nuts drying out the planks.

I have seen this done to several fishboats onthe Chesapeake and Delaware bays and it seems to produce the desired affect for quite a while.