OK, say I want to chop off the pointy ends of my old school slalom boat (Maverick), not so much to take advantage of the new rules but to make it less fragile and as a way to add the grab loops that were never there. Any suggestions? As evidenced by my previous posts, not only am I unskilled with glass work, but I am an outright coward. However, I think I can overcome both of these shortcomings...
Can this be done without removing the seams all the way around? What do you fill the void with? I've got a small amounts of cloth, some seam tape, and West Systems epoxy (quart cans).
Thanks in advance -
Scott
shortening a slalom boat
Moderators: kenneth, sbroam, TheKrikkitWars, Mike W., Sir Adam, KNeal, PAC, adamin
Shortening a Slalom Boat
Scott -
You can do it a couple of ways. The easiest way is to simply cut the ends off in sort of a radiused curve, then with minicell or some similar foam, fill in the open areas (bow and stern) - This will give you a form to lay your reinforcement over. Then using masking tape or electrical tape mark out the area that your reinforcement is going to cover - Sand this area well - best if you get to bare fiber.
Make a pattern of the area with cloth and use this pattern to cut your reinforcement. If you cut your reinforcement on a bias (45 degrees to the weave) , it will be a lot easier to make it conform to the curve.
I'd recommend a couple of layers kevlar (on the inside) and a couple of layers of 6oz or 10 oz glass over that. Glass sands a bot better than kevlar
I usually wet out a couple of layers at a time and put them on the boat - working out the bubbles. When you get all of the layers on, let it cure.
Sand the whole thing to blend it in to the existing seams, and then paint over it with pigmented resin
Let me know if this isn't clear.
F
You can do it a couple of ways. The easiest way is to simply cut the ends off in sort of a radiused curve, then with minicell or some similar foam, fill in the open areas (bow and stern) - This will give you a form to lay your reinforcement over. Then using masking tape or electrical tape mark out the area that your reinforcement is going to cover - Sand this area well - best if you get to bare fiber.
Make a pattern of the area with cloth and use this pattern to cut your reinforcement. If you cut your reinforcement on a bias (45 degrees to the weave) , it will be a lot easier to make it conform to the curve.
I'd recommend a couple of layers kevlar (on the inside) and a couple of layers of 6oz or 10 oz glass over that. Glass sands a bot better than kevlar
I usually wet out a couple of layers at a time and put them on the boat - working out the bubbles. When you get all of the layers on, let it cure.
Sand the whole thing to blend it in to the existing seams, and then paint over it with pigmented resin
Let me know if this isn't clear.
F
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ezwater
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Guest
Nice instructions, clt_capt. Good job, once again. You continue to be a wealth of boat building information and assistance.
If Scott can get the Walbridge book for some drawings and further written suggestions on doing similar "repair" jobs (and to read the all important safety instructions to protect himself from the toxic dust, fumes, etc. that he will encounter cutting and laying up glass with epoxy resin) he should do well with the help you have given.
I would suggest only that the stern be the first end to be shortened and reshaped. First attempts at significant glasswork are sometimes not as eye appealing as later attempts tend to be. If the bow is done second, it might be nicer to be looking at when paddling the modified boat.
Of course doing any shaping and layup work with glass is almost as easy to correct as is to screw up. Just cut off the parts that you are less than happy with and do the job again.
If Scott uses minicell to complete the shape of the ends he has trimmed, and glasses over that to form the new bow and stern, what is the easiest way to do the graploops he wants to add to his shorter boat?
And, considering that the boat owner is not skilled already, and because the bow and stern will tend to be stiff anyway (especially if he does end pours), why not use just glass cloth to build the new ends? Laying curves with 5 oz Kevlar cloth is much more difficult to do well than when using 10 oz e-glass. Glass is also a whole lot cheaper per square yard.
Scott, you need only to remove the parts of the boat that you don't want to retain. There is no need to remove the seams all the way around.
Before using the seam tape for constructing the ends, remove the selvedge from the sides of the tape. The glass tape will conform much more easily with the selvedge removed. If will also "feather out" and ease the air bubble removal process.
Have you considered what tool you are going to use to remove the bow and stern of your boat?
Do you have some experience using a circular saw? Getting much of a curve might be hard to do with such a saw.
I suppose a saber saw would work if you were cutting only through a thin laminate and not an end pour. A larger reciprocating saw would probably work for the thicker areas.
A hack saw could be used near the seam lines, but would be tough to work further in toward the center line of the deck and hull.
Maybe a combination of saws could be used to get the shape you want on both ends. Whichever saws you choose to use, be sure to use a sharp (new) blade designed for cutting fiberglass and plastic laminates. Carbide tips will help with the more difficult cuts through Kevlar.
If Scott can get the Walbridge book for some drawings and further written suggestions on doing similar "repair" jobs (and to read the all important safety instructions to protect himself from the toxic dust, fumes, etc. that he will encounter cutting and laying up glass with epoxy resin) he should do well with the help you have given.
I would suggest only that the stern be the first end to be shortened and reshaped. First attempts at significant glasswork are sometimes not as eye appealing as later attempts tend to be. If the bow is done second, it might be nicer to be looking at when paddling the modified boat.
Of course doing any shaping and layup work with glass is almost as easy to correct as is to screw up. Just cut off the parts that you are less than happy with and do the job again.
If Scott uses minicell to complete the shape of the ends he has trimmed, and glasses over that to form the new bow and stern, what is the easiest way to do the graploops he wants to add to his shorter boat?
And, considering that the boat owner is not skilled already, and because the bow and stern will tend to be stiff anyway (especially if he does end pours), why not use just glass cloth to build the new ends? Laying curves with 5 oz Kevlar cloth is much more difficult to do well than when using 10 oz e-glass. Glass is also a whole lot cheaper per square yard.
Scott, you need only to remove the parts of the boat that you don't want to retain. There is no need to remove the seams all the way around.
Before using the seam tape for constructing the ends, remove the selvedge from the sides of the tape. The glass tape will conform much more easily with the selvedge removed. If will also "feather out" and ease the air bubble removal process.
Have you considered what tool you are going to use to remove the bow and stern of your boat?
Do you have some experience using a circular saw? Getting much of a curve might be hard to do with such a saw.
I suppose a saber saw would work if you were cutting only through a thin laminate and not an end pour. A larger reciprocating saw would probably work for the thicker areas.
A hack saw could be used near the seam lines, but would be tough to work further in toward the center line of the deck and hull.
Maybe a combination of saws could be used to get the shape you want on both ends. Whichever saws you choose to use, be sure to use a sharp (new) blade designed for cutting fiberglass and plastic laminates. Carbide tips will help with the more difficult cuts through Kevlar.
Guest, Scott,
First - I would recommend against using seam tape for the repair. The selvage edge will keep it from conforming to the curves easily. You can pick up glass cloth at any hardware or auto parts store .If you cut the cloth on a bias (45 degrees to the weave) it will conform to just about any shape.
The reason I recommended kevlar (under the outer layers of glass) is that kevlar will take a lot more abuse than glass alone - The way I paddle, the ends of my boats always get beaten up. I'm pretty sure you can pick up a yard of Kevlar for less than $20 - check with John Sweet. Again if it is cut on the bias it will conform to any shape. If you get 5oz. kevlar with a style 285 weave, it will conform even cut straight because it is a crowfoot weave.
If you use the minicell method you can shape it anyway you want, and make it look like you didn't just hack the end off of the boat.
Depending on how the walls are installed in your boat and how much you are going to cut off of each end, you may not be able to do end pours, so having a few extra layers will be a good thing.
As for grabloops, If you are able to do endpours, the easiest thing to do is drill 2 small holes at each end which you can insert the rope into, and then do an end pour. You need to decide if you want your grab loops on the deck or hull - don't drill all of the way through.
If you decide to do the minicell method then what I'd suggest is to do is patch your ends, let them cure. then drill 2 holes (top to bottom) through the new patches - making sure to stay in the minicell portion. Place some tape over the bottom of each hole, and pour resin in to each hole - fill all the way to the top. Let it cure. Then using a smaller drill bit, drill all the way through these plugs. you can insert your rope in these holes once you have sanded the whole thing smooth(and painted it with pigmented resin).
As guest said Safety is important - gloves, respirator while messing with resin, dust mask or respirator when sanding.
F
First - I would recommend against using seam tape for the repair. The selvage edge will keep it from conforming to the curves easily. You can pick up glass cloth at any hardware or auto parts store .If you cut the cloth on a bias (45 degrees to the weave) it will conform to just about any shape.
The reason I recommended kevlar (under the outer layers of glass) is that kevlar will take a lot more abuse than glass alone - The way I paddle, the ends of my boats always get beaten up. I'm pretty sure you can pick up a yard of Kevlar for less than $20 - check with John Sweet. Again if it is cut on the bias it will conform to any shape. If you get 5oz. kevlar with a style 285 weave, it will conform even cut straight because it is a crowfoot weave.
If you use the minicell method you can shape it anyway you want, and make it look like you didn't just hack the end off of the boat.
Depending on how the walls are installed in your boat and how much you are going to cut off of each end, you may not be able to do end pours, so having a few extra layers will be a good thing.
As for grabloops, If you are able to do endpours, the easiest thing to do is drill 2 small holes at each end which you can insert the rope into, and then do an end pour. You need to decide if you want your grab loops on the deck or hull - don't drill all of the way through.
If you decide to do the minicell method then what I'd suggest is to do is patch your ends, let them cure. then drill 2 holes (top to bottom) through the new patches - making sure to stay in the minicell portion. Place some tape over the bottom of each hole, and pour resin in to each hole - fill all the way to the top. Let it cure. Then using a smaller drill bit, drill all the way through these plugs. you can insert your rope in these holes once you have sanded the whole thing smooth(and painted it with pigmented resin).
As guest said Safety is important - gloves, respirator while messing with resin, dust mask or respirator when sanding.
F
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sbroam
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Thanks for all of the input! I do have Walbridge's book and it was me that posted about adding grab loops a while back (and about what to do about the "fuzzies" on the hull). I haven't gotten round to those projects just yet either, though I think I can handle those (independent of chopping)...
This sounds like one of those kinds of projects I'd be inclined to avoid or pay somebody to do - "knowing ones limitations", lack of time and hesitance to experiment on the one glass boat I have. My previous experiences laying up fabrics have not gone well. Even better, would be to do this *with* someone who knows how...
This sounds like one of those kinds of projects I'd be inclined to avoid or pay somebody to do - "knowing ones limitations", lack of time and hesitance to experiment on the one glass boat I have. My previous experiences laying up fabrics have not gone well. Even better, would be to do this *with* someone who knows how...
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John Coraor
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Shortening a C-1
There is an easier method that might work if your're only shortening the boat a little (i.e. blunting the ends). The wider and deeper the boat is at the point to which you're shortening, the less desirable this method becomes (i.e. it's great for loping some off that thin stern, but taking a larger amount off the bow wouldn't work too well).
Composite boats typically have their ends sealed with a small "end pour" of resin mixed with milled glass fibers. On really narrow ends, like the stern of most slalom boats, this can extend quite a ways from the end due to the thinness of the boat making inside seaming impossible in the ends. If the end pour extends a least a couple inches past the point to which you are shortening the boat, then you're in luck. If not, you should be able to extend the pour with a new application of resin & milled fibers. Just stand the boat up vertically and pour the necessary amount of new resin & milled fibers into the end on the ground. (Wallbridge gives some tips on this (i.e. disposable cup on a string lowered to just above the end, which is then tipped over by pulling on another string attached to the bottom of the cup. Just make sure you use cups that don't dissolve from contact with the resin.)
If done properly, a resin end pour is solid and can be cut with a sabre saw and then ground to any shape with a sanding disk (wear a dust mask). If desired, the exterior of the shaped pour can then be reinforced with kevlar or other composite cloth (cut on the bias to enhance flexibility) just as suggested above. However, if the amount of plug exposed on the end isn't huge, I've gotten away with just leaving it as it after sanding.
There are generally two ways to add grab loops with a solid end pour. The John Sweet method, which will work with either a new or an old pour, is to drill one or two holes vertically all the way through the deck, end pour, and hull - then just thread the grab loop through. You can do only one hole and just leave the loop dangling to one side or the other, or the classic Sweet method was two holes with the loop knoted underneath (yes, it dangles down below the hull). I've never used the other method, which requires adding a new pour. You drill two holes in the deck just big enough to fit the end of the grab loop. Fray the ends, shove them through so that the frayed ends will anchor inside the pour, tape the loop in place, and do your pour.
I think you can see that if you're going to take a lot off of either end, and particularly the bow, the size of the end pour required begins to be prohibitive using this method. However, if you're just blunting the ends a bit, it is probably easier to simply grind resin than it is to shape foam and apply kevlar, etc. This method works particularly well for pre-1986 slalom boats like the Batmax, Cudamax, Torrent & Torrent XL C-2s etc. - who all had very narrow stiletto bows (usually filled with the end pour) just begging to be lopped off.
Composite boats typically have their ends sealed with a small "end pour" of resin mixed with milled glass fibers. On really narrow ends, like the stern of most slalom boats, this can extend quite a ways from the end due to the thinness of the boat making inside seaming impossible in the ends. If the end pour extends a least a couple inches past the point to which you are shortening the boat, then you're in luck. If not, you should be able to extend the pour with a new application of resin & milled fibers. Just stand the boat up vertically and pour the necessary amount of new resin & milled fibers into the end on the ground. (Wallbridge gives some tips on this (i.e. disposable cup on a string lowered to just above the end, which is then tipped over by pulling on another string attached to the bottom of the cup. Just make sure you use cups that don't dissolve from contact with the resin.)
If done properly, a resin end pour is solid and can be cut with a sabre saw and then ground to any shape with a sanding disk (wear a dust mask). If desired, the exterior of the shaped pour can then be reinforced with kevlar or other composite cloth (cut on the bias to enhance flexibility) just as suggested above. However, if the amount of plug exposed on the end isn't huge, I've gotten away with just leaving it as it after sanding.
There are generally two ways to add grab loops with a solid end pour. The John Sweet method, which will work with either a new or an old pour, is to drill one or two holes vertically all the way through the deck, end pour, and hull - then just thread the grab loop through. You can do only one hole and just leave the loop dangling to one side or the other, or the classic Sweet method was two holes with the loop knoted underneath (yes, it dangles down below the hull). I've never used the other method, which requires adding a new pour. You drill two holes in the deck just big enough to fit the end of the grab loop. Fray the ends, shove them through so that the frayed ends will anchor inside the pour, tape the loop in place, and do your pour.
I think you can see that if you're going to take a lot off of either end, and particularly the bow, the size of the end pour required begins to be prohibitive using this method. However, if you're just blunting the ends a bit, it is probably easier to simply grind resin than it is to shape foam and apply kevlar, etc. This method works particularly well for pre-1986 slalom boats like the Batmax, Cudamax, Torrent & Torrent XL C-2s etc. - who all had very narrow stiletto bows (usually filled with the end pour) just begging to be lopped off.