Shortening rx boat? How
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Shortening rx boat? How
I have a bell prodigy that has a hole in the bottom and I want to cut about a foot and a half out and then put it back together. Has anyone done this or does anyone have any tips. the hull is pretty soft in the middle anyway so I figure it could be a fun little project. Any tips are appreciatted
Paul Mason's book
Well, Paul Mason in "Thrill of the Paddle" mentions that he and his friends used to do this a lot. I have not attempted such a modification, but I would (1) be sure to use epoxy resin (2) design the patch so that it was fairly flexible (e.g, have mostly polyester cloth in the lay-up), (3) make the patches well feathered (one 2"-wide layer, then a 4" layer,...), and (4) put most of the patch layers on the inside of the boat.
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Guest
Given the Prodigy's asymmetrical hull (with very different amounts of rocker at the bow and stern, a significant chine hardening towards the stern, and the vastly different shears along the length of the hull), I think you will have a terrible time getting the shortened fore and aft pieces of the "amputated" Prodigy hull aligned into anything that won't be a real dog to paddle.
You'd have a better chance of getting a good paddling canoe by chopping down a tree in your backyard and doing a dugout.
If you think your proposed modification of a fine canoe design is going to be an improvement, then do a one-off in glass from the old ABS hull, chop the one-off to length by removing a length of midsection, adjust the width at the joint, set the rockers, realign the keel line, and get out a couple cases of Bondo to slap on your plug to get the lines and curvatures faired.
When you are tired of sanding and shaping that plug, build a prototype mold, and make a paddlable plug from it. When that plug is right, do another mold/plug (or two) and make your "chopped prodigy" in glass from the final production mold.
By then, you should know better than to try to pull at the collective leg of the experienced boat designers and builders that like to post here.
Of course, if you want to stay with an ABS hull, you can either patch the hole in your Prodigy, or kiss it goodbye and go boat shopping.
Are we having fun yet?
You'd have a better chance of getting a good paddling canoe by chopping down a tree in your backyard and doing a dugout.
If you think your proposed modification of a fine canoe design is going to be an improvement, then do a one-off in glass from the old ABS hull, chop the one-off to length by removing a length of midsection, adjust the width at the joint, set the rockers, realign the keel line, and get out a couple cases of Bondo to slap on your plug to get the lines and curvatures faired.
When you are tired of sanding and shaping that plug, build a prototype mold, and make a paddlable plug from it. When that plug is right, do another mold/plug (or two) and make your "chopped prodigy" in glass from the final production mold.
By then, you should know better than to try to pull at the collective leg of the experienced boat designers and builders that like to post here.
Of course, if you want to stay with an ABS hull, you can either patch the hole in your Prodigy, or kiss it goodbye and go boat shopping.
Are we having fun yet?
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nam
use a card board and trace the shape of the boat where you are going to make the first cut, also lmake a mark on the boat where you decided to cut. and then cut the board out.Like a half moon shape. Hard to explain...
Take that shape and move it down to the other side of the boat slide it until it matches the shape. Mark it down(cut #2) Now you have equal joinning spots. Don't use west epoxy hard stuff. tHEY ARE NOT THAT GREAT AND CAN CRACK AND..NOT ALOT OF GIBING FOR THE JOINTS so the ends will come apart. There are stuff that are more flexible and way better than west epoxy. uses kevlar cloth for sure. I've seen guys also to that to the top front of the boats. look really great and. Lots of people used to do it on th Ottawa river...using the Ocoee. Hope this help.
Fun project if you have time.
Yeah Paul Mason talked about it in his books.. wonder if i can get some pics
nam
Take that shape and move it down to the other side of the boat slide it until it matches the shape. Mark it down(cut #2) Now you have equal joinning spots. Don't use west epoxy hard stuff. tHEY ARE NOT THAT GREAT AND CAN CRACK AND..NOT ALOT OF GIBING FOR THE JOINTS so the ends will come apart. There are stuff that are more flexible and way better than west epoxy. uses kevlar cloth for sure. I've seen guys also to that to the top front of the boats. look really great and. Lots of people used to do it on th Ottawa river...using the Ocoee. Hope this help.
Fun project if you have time.
Yeah Paul Mason talked about it in his books.. wonder if i can get some pics
nam
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Guest
IMO, using Kevlar to rejoin two pieces of ABS (torn or cut) is usually a mistake.
Kevlar is a very stiff when used in a laminate, and you want extreme flexibility when "repairing" the ABS sandwiches from which canoe hulls are made.
So, use nylon or polyester with a little glass to construct your patch. (If you know how to properly saturate Kevlar for the most efficient resin-to-cloth ratio, then you can substitute a little of it for some of the glass component in the laminate to save a little weight. However, unless you are very good, or are vacuum bagging the joint to make the repair, stick with lots of nylon/little bit of glass formula for your patch.)
Doesn't really matter what resin you use to construct the patch. Nothing sticks well to ABS under stress, so almost any of the epoxies or vinylester resins will have to do. (BTW, using a polyester resin is a waste of time and materials. It will not adhere to ABS worth a dam.)
While I have heard of some glue formulas (3M) that reportedly can create chemical bonds with ABS, these adhesives are so expensive that repairing an ABS canoe with them is really not very cost effective.
Because you will have a weakened and less streamlined hull no matter what adhesive you use to repair an ABS hull, it is really best to put your money into a new boat. I think you get more value with a new material, rather than one that is worn, sun damaged, and also patched with materials that are, for the intended use, inherently inferior to that of the original construction.
Kevlar is a very stiff when used in a laminate, and you want extreme flexibility when "repairing" the ABS sandwiches from which canoe hulls are made.
So, use nylon or polyester with a little glass to construct your patch. (If you know how to properly saturate Kevlar for the most efficient resin-to-cloth ratio, then you can substitute a little of it for some of the glass component in the laminate to save a little weight. However, unless you are very good, or are vacuum bagging the joint to make the repair, stick with lots of nylon/little bit of glass formula for your patch.)
Doesn't really matter what resin you use to construct the patch. Nothing sticks well to ABS under stress, so almost any of the epoxies or vinylester resins will have to do. (BTW, using a polyester resin is a waste of time and materials. It will not adhere to ABS worth a dam.)
While I have heard of some glue formulas (3M) that reportedly can create chemical bonds with ABS, these adhesives are so expensive that repairing an ABS canoe with them is really not very cost effective.
Because you will have a weakened and less streamlined hull no matter what adhesive you use to repair an ABS hull, it is really best to put your money into a new boat. I think you get more value with a new material, rather than one that is worn, sun damaged, and also patched with materials that are, for the intended use, inherently inferior to that of the original construction.
To those of you who gave some tips I thank you, to the anonymous Guest with the second response, please don't respond unless you are giving me info that is worth while instead of going on some angry tangent 
, the boat is trash anyway so why not have fun trying something rather than tossing it in the trash as I have a new boat on the way. I'm not designing a new boat I am recycling a used one. Again to those of you who responded with useful info you have definetely given me some things to think about and consider so thank you very much!!
, the boat is trash anyway so why not have fun trying something rather than tossing it in the trash as I have a new boat on the way. I'm not designing a new boat I am recycling a used one. Again to those of you who responded with useful info you have definetely given me some things to think about and consider so thank you very much!! -
sbroam
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I've used ABS cement and pieces of ABS to patch wear spots on royalex boats. I hadn't thought of using it to rejoin a chopped boat but it might work - you'd need to sand through the vinyl to the ABS for a good bond, though. I would see a 12 - 18" wide piece of ABS running from gunwale to gunwale on the inside and again on the outside. I'd be careful about getting the ABS cement on the exposed foam layer, I suspect the solvent could eat that up. I wouldn't take it on a wilderness run, though I'd be interested to hear how well it worked 
I think the notes about the assymetry of the Prodigy are certainly valid - the wider you make your cut, the harder to join back it will be. The Ocoee is pretty symmetrical (perfectly so?) making it easy to chop.
And while resin may not adhere to plastic as well as it does to other materials, folks have been modifying boats this way for quite a while. It must work well enough because they keep doing it. Maybe not as often now that there are some new designs floating around (so to speak)...
I think the notes about the assymetry of the Prodigy are certainly valid - the wider you make your cut, the harder to join back it will be. The Ocoee is pretty symmetrical (perfectly so?) making it easy to chop.
And while resin may not adhere to plastic as well as it does to other materials, folks have been modifying boats this way for quite a while. It must work well enough because they keep doing it. Maybe not as often now that there are some new designs floating around (so to speak)...
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anonymous Guest with the
Gee, I was pretty sure you were having some fun at the expense of the authors of the recent boat building threads. How was I to know that you were serious about doing something as ludicrous as chopping a couple feet out of the middle of a Prodigy? 
That boat is very poorly suited for such an endeavor because of the pronounced asymmetry of the hull. I figured that would be obvious to the most casual observer, but maybe the hole in the middle of yours has been distracting to your vision.
So, while I regret misinterpreting your stupefying idea as being an attempt at sarcastic humor, you did ask, "does anyone have any tips?"
Based on my experience, I am quite sure the tips I offered are worthwhile. After (if) you gain more experience, you might even find them to have been prophetic. I repeat my tips here, but rather than being tangential, I have stated them quite directly (kind of like whacking a mule with a 2X4):
1. You will have great difficulty reconnecting the dissimilar ends of a Prodigy when you have removed a couple feet from the middle. They will not line up for a smooth transition of lines from stem to stern. (Think putting a square peg into a round hole.)
2. If you do get the ends reconnected by (applying lots of heavy layers of resin and cloth), the chance of your having been able to maintain a straight line along the keel line (that’s the bottom center of the boat) is miniscule. This means the boat will lose its already limited ability to track in a straight line.
In addition, you will have to pay very close attention to the changes you will have to make to the rocker at both the bow and stern. (The Prodigy has a different amount of rocker at each end, and even if you are able to maintain both original dimensions, they will function differently with the reduced hull length.) This means the turning ability of the boat will be altered vastly.
3. After you have lumped the ends together, your "recycled" hull will be a real squealer to paddle. (Think: Oink! Oink!) I suppose some people aspire to paddle very ugly boats that will not easily turn and do not track well, but is that really “you” cbcboat?
4. This is an added bonus tip: After you have removed the center section of your Prodigy, use some sheet aluminum pop-riveted into place to temporarily reconnect the ends. Attach some "quick and dirty" gunnels to your hulk (rather, hull.) A couple lengths of PVC pipe will probably do the job, although I think the remaining differential in shear will make even that a daunting task. Then slap some duck tape on the hull joint to help keep most of the water out, and take your "project" for a test spin. I predict your next stop will be the landfill (for a proper "recycling" of your former Prodigy.)
Of course, if you show up at the Armada with the hottest redesigned open canoe on the river, I will gladly eat these words.
Until then, please consider this my final piece of advice to you:
When telling me (or anyone else) what and how to post here in response to an open question/ request for assistance remember that if you don't want to hear a stupid answer, then don't ask a stupid question.
Are we having fun yet?
That boat is very poorly suited for such an endeavor because of the pronounced asymmetry of the hull. I figured that would be obvious to the most casual observer, but maybe the hole in the middle of yours has been distracting to your vision.
So, while I regret misinterpreting your stupefying idea as being an attempt at sarcastic humor, you did ask, "does anyone have any tips?"
Based on my experience, I am quite sure the tips I offered are worthwhile. After (if) you gain more experience, you might even find them to have been prophetic. I repeat my tips here, but rather than being tangential, I have stated them quite directly (kind of like whacking a mule with a 2X4):
1. You will have great difficulty reconnecting the dissimilar ends of a Prodigy when you have removed a couple feet from the middle. They will not line up for a smooth transition of lines from stem to stern. (Think putting a square peg into a round hole.)
2. If you do get the ends reconnected by (applying lots of heavy layers of resin and cloth), the chance of your having been able to maintain a straight line along the keel line (that’s the bottom center of the boat) is miniscule. This means the boat will lose its already limited ability to track in a straight line.
In addition, you will have to pay very close attention to the changes you will have to make to the rocker at both the bow and stern. (The Prodigy has a different amount of rocker at each end, and even if you are able to maintain both original dimensions, they will function differently with the reduced hull length.) This means the turning ability of the boat will be altered vastly.
3. After you have lumped the ends together, your "recycled" hull will be a real squealer to paddle. (Think: Oink! Oink!) I suppose some people aspire to paddle very ugly boats that will not easily turn and do not track well, but is that really “you” cbcboat?
4. This is an added bonus tip: After you have removed the center section of your Prodigy, use some sheet aluminum pop-riveted into place to temporarily reconnect the ends. Attach some "quick and dirty" gunnels to your hulk (rather, hull.) A couple lengths of PVC pipe will probably do the job, although I think the remaining differential in shear will make even that a daunting task. Then slap some duck tape on the hull joint to help keep most of the water out, and take your "project" for a test spin. I predict your next stop will be the landfill (for a proper "recycling" of your former Prodigy.)
Of course, if you show up at the Armada with the hottest redesigned open canoe on the river, I will gladly eat these words.
Until then, please consider this my final piece of advice to you:
When telling me (or anyone else) what and how to post here in response to an open question/ request for assistance remember that if you don't want to hear a stupid answer, then don't ask a stupid question.
Are we having fun yet?
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anonymous Guest with the
now now, let's all be friendly here!
The way I see it... if you're definately going to throw it in the trash anyways, you might as well have some fun with it first... you may end up with a piece of junk, and have learned something from the experience, or maybe you will end up with a functional boat that you really enjoy.
as far as the guest's comments go... maybe I don't know much about boat design, but won't a boat that can't go in a straight line turn really really well?? might not carve worth crap, but i imagine you'll be able to turn the thing.
have fun out there, and hopefully learn some new things! i think that's why we all paddle anyways.
cheers,
-allan
The way I see it... if you're definately going to throw it in the trash anyways, you might as well have some fun with it first... you may end up with a piece of junk, and have learned something from the experience, or maybe you will end up with a functional boat that you really enjoy.
as far as the guest's comments go... maybe I don't know much about boat design, but won't a boat that can't go in a straight line turn really really well?? might not carve worth crap, but i imagine you'll be able to turn the thing.
have fun out there, and hopefully learn some new things! i think that's why we all paddle anyways.
cheers,
-allan
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sbroam
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Hey now, let's watch the tone here - this isn't BoaterTalk. I think it is clear that cbcboater just wants to try something out with an otherwise now useless boat and that "guest" (#1?) takes boat design and construction very seriously. We all have many opportunities to learn - from informative posts here on this the definitive site for C-boating on the net, from hands on messing around with available materials, from precise and deliberate study, etc...
Everybody take a deep breath, step away from your keyboards, and head to the river. I think I may just clean up those last couple of posts - no sense letting this site's first profanity (not from a hacker) lie around where just anybody could step in it.
Everybody take a deep breath, step away from your keyboards, and head to the river. I think I may just clean up those last couple of posts - no sense letting this site's first profanity (not from a hacker) lie around where just anybody could step in it.
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montana c-1
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Hey arent we all supoosed to be having a little fun here. It is really funny to see all these posts about boats and what to do with them. I thought that the funniest was the third post where the " guest" ( who doesn't have enough gull to sign in and tell us who he/she is) said that by the time we make a patch we " should know better than to pull at the collective leg of experienced boat builders."
Thats why cbcboat asked the question to get tips not get knocked down for a fun project. If people were not chopping boats in half to begin with and making crazy concoctions out of plastic we wouldn't have a lot of the boats that we have today.
So a little advise to our so called " guest"
Cheer up and have a little fun don't sit on c-boats all day and make fun of people. go out and paddle. Hey maybe we will see you out there in our chopped up prodigy throwing wheels in your face.
I said my peace. Now And I am going to help Cbcboat chop that boat in two!!!!!!!!!
Thats why cbcboat asked the question to get tips not get knocked down for a fun project. If people were not chopping boats in half to begin with and making crazy concoctions out of plastic we wouldn't have a lot of the boats that we have today.
So a little advise to our so called " guest"
Cheer up and have a little fun don't sit on c-boats all day and make fun of people. go out and paddle. Hey maybe we will see you out there in our chopped up prodigy throwing wheels in your face.
I said my peace. Now And I am going to help Cbcboat chop that boat in two!!!!!!!!!
one blade one LOVE
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Louie
I think I have one in my wearhouse that had been shorternec
I do think it is one the Canadians did. they just cut a foot or two out of the middle of an Ocoee and then glassed it back together with about a 2 foot patch.