Need information on old hull repair

Discusion related to all older Folbot models Pre Hugo! (1990)

Need information on old hull repair

Postby C_Swenson » Mon May 23, 2005 10:24 pm

I am new to folding kayaks. I have been saving up for a Greenland II double kayak to migrate out of my canoe. This last Saturday morning, totally out of the blue, I picked up a older Folbot single at a garage sale for a whopping $10.00. This might be an acceptable starter boat to get me on the water and add another boat for the family. The frame seems to be serviceable with one or two minor repairs at the stern, but I fear that the lower hull has aged a bit too much.

The outer layer on the hull, vinyl I think, has a brown discoloration and is separatingin flakes from the under layer of tough fabric. Needless to say I have a few questions.

1) Can you help me identify the model and date of manufacturer by looking at the frame and hull pictures? The only alphanumeric coding I have seen thus far is a M2 stamped on the insides of the carrying bags?

2)Can I peal back all the damaged cracking material from the lower hull and attach a new surface of EDPM as described in Ralph Dias's book?

3) If the EDPM will not work; is there another surface treatment out there that can add some life to the hull?

4) Am I better off selling the frame & components and putting the money toward
a newer kayak?

I am attaching some pictures that may help you identify the kayak. Many thanks for your help and support.

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Postby bagboater » Mon May 23, 2005 11:33 pm

How long is it? Might be a Super Single. Doesn't look like a Sporty.

At that price it would be worth trying to fix. If you can't find a way to re-coat the hull you could seperate the hull and deck at the seams and use it for a pattern to cut a new hull. Sewing it back together is the hard part. A tent and awning shop could sew it for you and may be able to come up with a near match for the fabric. Good luck.
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Postby folbot » Tue May 24, 2005 12:13 am

I suspect it is a Sporty. The SPF or folding version of the Sporty had a cockpit that was pointed on both ends as opposed to the SPK or kit version that had a single pointed cockpit.
That skin looks pretty sad, but the frame appears to be in pretty good shape. I agree with bagboater that it certainly would be worth a try at restoring. Check Seattle Fabrics They have a wide array of fabrics that could be useful. I think the Vinyl coated polyester would come the closest to the original material. Using the original skin as a pattern is probably the best bet since it looks like it is at least all in one piece.
The Sporty has great lines and is a nice handling boat. Good luck and keep us posted on your progress.
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Looks like a Sporty to me ...

Postby River Rat » Tue May 24, 2005 12:25 am

It's a Sporty, looks much like mine except that someone has added the cushioned seat back and float bags (which were optional equipment). Not sure what to tell you about remaking the hull, I think it'd be a difficult job even finding some place that could sew through fabric that tough and rubbery. If the flaking isn't through to the fabric layer, then I wouldn't worry about it too much if I were you.

Sporty stats (from Folbot Holidays 1966): 15' long, 32" wide, 45" cockpit, 54 lbs.

Good deal, by the way, it's a nice boat (though I hope that yours assembles and disassembles rather better than mine does after all these years). Did yours come with the spray skirt?

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Re: Looks like a Sporty to me ...

Postby C_Swenson » Tue May 24, 2005 4:56 am

River Rat:
You said: "If the flaking isn't through to the fabric layer, then I wouldn't worry about it too much if I were you."

Looks like you think I may have a non-problem. The flaking isn't through the fabric layer. That layer still seems soft and flexible. Looks like the vinyl got zapped with UV or something. Are you suggesting that I might be OK if I just remove the vinyl flakes off the hull and proceed?

There was no spray skirt. I really like the price.
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Postby PeteS » Tue May 24, 2005 9:21 am

That's a Sporty okay. Circa 1981-1982. Great boat! Mine has many many miles on it. The stuff peeling off looks like vinyl paint! If the material underneath is smooth, then it's the original hypalon (should be gray). If there are threads like canvas then that was really the outside protective layer peeling off (I find that hard to believe). You can be very safe in that boat!
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Postby River Rat » Tue May 24, 2005 1:37 pm

Actually, it looks almost identical to my Sporty, which is mid-60's vintage. But I wouldn't know what differences to look for between 1960s and early 80s versions.

Ah, looking through the 1984 catalog (from when I rebuilt my Sporty after wrapping it around a tree in the river), I see that they did indeed at that time offer a brown hull color (other choices in 1984 were green, red, blue, and white). So it probably isn't paint.

I'm not sure what is flaking on your hull, maybe even some sort of wax or coating? My GUESS is that as long as the hull material is still flexible (not cracking), and the flaking does not penetrate to the cloth core, the hull is still sound enough for use. Not very pretty with that flaking, I'd try to gently rub as much of the flaking material off as possible and see whether the material underneath begins to disintegrate or not.

By the way, if that boat is as old as mine, it predates Hypalon, the hull was made of vinyl over a fabric core (the deck material being a much lighter weight than the hull). Hypalon was supposed to be tougher and lighter than the original fabric, unfortunately the rocks in the rivers I paddle don't seem to know that :)

Hope this is of a little help,

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Reskinning folbot

Postby kenzo » Sat May 28, 2005 1:50 pm

Certainly worth saving.Looks to me like the original unaltered hull as I have a Super TSF double of identical colors. One route (the skin apparently serviceable )would be to just use it until it gives up precluding of course any long sea journeys. Otherwise you might look into the excellent instructions provided by Thomas Yost ( skinning folders using 9 oz polyester with hypalon/neoprene sealers or 18oz.PVC. It will be something of an undertaking. Or if you don't care about foldability there is much out there on sewing on canvas Greenland -style which would give you a lighter boat. You've got a head start with your existing 'patterns'. Good Luck
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Update on Progress

Postby C_Swenson » Thu Jun 09, 2005 8:10 am

The frame cleaned up nicely. The stern wood fitting was easily patched using S2-glass tape and a marine epoxy. The unit was "ready" for a trial assembly. This first attempt was a painful experience that did not meet success.

1) Does anyone have any documentation of the assembly sequence?
2) Is it possible that the hull has shrunk in the bag over the 20 years?
3) It looks like the zipper was a major folding-kayak design inovation.
4) I am looking into making a new hull using the Yostwerks process.
5) Data would be appreciated.

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Re: Update on Progress

Postby redsail » Thu Jun 09, 2005 9:24 pm

C_Swenson wrote:UPDATE
..... 2) Is it possible that the hull has shrunk in the bag over the 20 years? .....

Yes. The older hulls were cotton canvas impregnated with vinyl. The cotton did shrink. Jack Kissner (Folbot founder) had some recommendations for what to do if the hull did shrink. I think Cliffy still has those. He also has other recommendations about what to do.

Another thing: In his catalog Kissner stated that assembly and disassembly of the Sporty SPF was more difficult than for the other Folbots. He advised not get get it if you were going to assemble and disassemble a lot.
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Assembling the Sporty

Postby PeteS » Thu Jun 09, 2005 11:04 pm

C_Swenson, one of the things that will help the assembly of an older Sporty is the following: file the notches in the wooden frames to the angle of the boat (they come square from the factory because they were made on a bandsaw, then routered on the edges). This will allow the longerons to seat deeper in the frames, hence, narrow the width of the frame assembly and allow it to slide all the way into the skin.
Note: 2. Only put the front 2 cross frames on the assemble before inserting it into the skin. Same with frame #7 of the stern assembly (This will allow easy installation of the secondary longerons). Once both halves are in and the floorboards pushed down, secondary longerons installed, THEN install frame #3, #6, #5 and #4 in that order.

Note: frame #3 and #6 have the deck support attached via a brass fitting. Since it is difficult to push up the deck enough to hook the fitting, I do the following: attach a 6" diameter loop of 1/8" line on the deck support. This gives you a handle to lift the support into position. You can either leave the loop on or untie it afterwards. BTW, if you use rope too fat, it won't fit through the small opening in the deck in front of the frame (behind the #6 frame).
Awww, that's enough for now.

If you can't push the floorboards down because the skin is too SHORT, there is a fix for that too.
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Postby cliffy » Fri Jun 10, 2005 8:00 am

Wood frame shortening..... from instructions..... note on the pic... movement of the longerons towards the ends of the frame... and .. as a last resort.... shortening of the frame member..... very last resort there..

Also.... you may have a skin that has survived ..... near.... a fire or next to a heater or the like...... it may have gotten really hot......
flake it off.... see if there is any vinyl left on the woven part of the skin locally or if it's a coating....
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Postby River Rat » Mon Jun 13, 2005 11:40 pm

Like the above posts said, assembly can be very difficult, which is one reason why my Sporty doesn't get disassembled more than once a decade. At one point I had to use a jack to force the center of the deck up high enough to hook onto the top of the rib at the rear of the cockpit.

As best I recall the process:

1. Unroll the skin the the hot sunshine to help make it a bit more flexible.
2. Attach the front three (I think?) ribs to the forward assembly, and the last two (I think) ribs to the rear assembly.
3. Slide the forward assembly into the front of the skin, and the rear assembly into the rear of the skin.
4. Interleave the metal plate in the center of the cockpit floor, and stand on it, this forces the front & rear assemblies into the ends of the skin.
5. Insert and attach the rib at the front of the cockpit (number 4?) and the one at the rear of the cockpit (number 6?). I would NOT attach the runners at the forward and rear peak of the deck yet.
6. Insert the six short aluminum tubes in the cockpit area. This is in my experience one of the most difficult parts, as the tubes don't fit particularly well, and the metal sliders frequently get jammed.
7. Attach the wooden runner under the peak of the deck to the ribs at front and rear of the cockpit. This can be very difficult, as I said I once had to use a jack to force one up high enough.
8. Insert the 'U' shaped rib and the rib with the seat. Getting the side aluminum poles to seat properly can be difficult, on mine the holes for the little brass hooks no longer align with the ribs.
9. Slide the cockpit gunwales onto the bead along the edge of the skin. The holes at the ends of the gunwales are to seat the pins on the brass fitting of the ribs at either end of the cockpit. Once the pins are seated in the holes, put the cast aluminum fitting over and hold it down with the brass T-bolt.
10. Slot the four brass clamps on the gunwales through the holes in the brass fittings of the two ribs in the cockpit (the U-shaped one and the seat rib), then turn 90 degrees and clamp then to the gunwale.
11. Swear that you will never, ever take the darn thing apart again! :)

Good luck!
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