Wooden Boat People
By McKenzieDriftBoat.com
Building for big water and looking for options.
For some background on white water take a look at the images at the following site. Some of the images are from Joe Hutch rapid on the Green at a flow of 25000 CFS a class IV run.
http://www.inskeepimages.com/g/highwaterdeso
People with GPS units on their boats have reported boat speeds through the rapid at over 20 MPH.
The dory images are of Linclon Frye, Ryan Pearl and Dave Inskeep. Each built the boat they are rowing. Ray Bloxham is running my boat which I built about 8 years ago.
Dave Inskeep runs a 16 foot all wood Tatman design modified for whitewater. The boat is over 10 years old, has run the Grand Canyon twice and has never had a hole in it. It makes it's third trip down the Grand next March.
We are not talking about fly fishing drift boats here. As we all know wooden drift boats are more then up to the task for class III water. We may need to fix a dig now and then but these boats will last a lifetime. However, I wouldn't advise running a Hyde or Tatman open fishing rig through Joe Hutch at 25000 or Lava at 10000 if you don't want it swamped and pinned on the rocks at the bottom of the river. This is not to imply there is anything wrong with either boat. I don't like fishing from my decked white water boat, the right tool as they say.
Who cares? Well, In the last 4 years I have been on 3 trips where there have been dories which could not continue until repairs were make. I also know of 3 other events on trips I was not able to make. All of this carnage happened to highly skilled boaters. It's just part of the deal. Being and old weak dude I look for the anti-carnage line whenever possible. One boater I know likes to say “go big or go home”. Well, he does and sometimes with a hole in his boat. We have fun and do what we can.
Lets try to apply some number to this. With the added weigh of bulkheads and decks let's say a 16 foot whitewater boat will be around 500 pounds. Add 2 adults, safely gear, cooler, food, camping equipment, water etc. Just call it 1000 pounds for a loaded boat. A large 17 foot Briggs boat will be more.
Now think about riding up a wave at 15 MPH and going down the back side into the trough and coming down onto a rock. 1000 pounds of force plus some added component with the boat moving downward. This isn't a math class (F=MA and all that stuff) so we will call it some number of pounds of force well above 1000 pounds. The rock is around 6 inches square or 36 square inches. 1000 pounds of boat and gear being dropped onto a 6 X 6 inch square. We also know from basic chemistry that liquids and solids are not compressible. So, when we hit the rock were does the 1500 pound impact energy go?
Options
We could crush the rock,,,,,, or not
The bottom of the boat could bend or not if we have bulkheads or frames.
If the rock doesn't crumble and the boat bottom can't bend then it will be the bottom of the boat which will brake. The energy will be converted into heat as it brakes the wood fibers and fiberglass as it folds inward.
How thick would the plywood and frames/bulkheads need to be to prevent this breakage? I don't know how thick it would be but it's too thick for a boat and the boat becomes 500 pounds heavier. If you want to build from wood that's fine but then you must live with the properties of the material and be willing to fix some things when you get pushed off line and take a big hit. There is no way around it and we have been doing just that for a long time.
What else can we do?
1 --
Make the bottom flexible. This sends some of the impact load to the surrounding material as it flexes. Like old time bridging of floor joist. Step on one floor joist and as it bends downward we send some of the load to the joist on each side of us. The impact now loads 200 square inches instead of 36. Unfortunately this is not an option when frames or bulkheads are being used.
2 --
make the bottom stronger so we can prevent the impact from braking the plywood by sending the load through more wood fibers to the material around the impact. Less psi on a bigger area to bring the load down to what the material can handle. Much thicker plywood. This would send the impact load down the fibers of the wood and with more plywood layers at some point the wood becomes strong enough not to brake if we make it think enough. This option is not practical beyond ½ inch plywood due to the added weight.
3--
Different materials.
Honeycomb, some of us have already started using this.
If you are building a wood white water boat the only option is to go with ½ inch plywood and cover it with kevlar which brakes at a much high load then glass fiber. I don't know of any other way. This will make a fine boat and over the years we will just need to fix it when we put a hole in the bottom. Not the end of the world. We pull the boat out of the river and thank the person who needs to mix up some epoxy for the patch for giving us a layover day. We can point to the fixes and toast the past which is nice. We can fix anything the river throws at us given enough time, beer and epoxy.
Now if we use ¾ or 1 inch honeycomb in place of the plywood we have a much lighter material since most of it is hollow. When the load of the impact is applied to the 6 X 6 inch area the inside of the honeycomb will start to deform dissipating much of the energy before it gets to the inside surface. If the impact load is high enough it will also brake the fiberglass on the outside as it crushes the honeycomb material just like with plywood. Now replace the fiberglass with Kevlar. Since the Kevlar is mush stronger then glass and does not want to stretch, the impact will try to stretch the fibers sending the load to a much larger area. This sends the impact energy into lets say 200 square inches of honeycomb taking away enough of the energy to prevent the rock from punching through. The thicker the honeycomb the more it can crush without getting all the way through and the kevlar sends the force to more of the honeycomb. Like stretching a trampoline over the outside of the boat so it can bounce off rocks.
Lets say the rock hits right next to the frame/bulkhead and the impact load is so high that the honeycomb just can't absorb it all. Then just like with plywood it folds inward and we have a hole in our boat. How could we stop this one? If we all agree that the honeycomb with kevlar is stronger then plywood what do we do now? What if the bottom could flex? What if the frames or bulkheads were not their? Then the entire bottom could bend inward sending the impact load to many square feet not just a few inches. Now we can take a much larger impact. How can we do this with a frame? I have no idea but we can do it with a bulk head. If the bulkhead does not go all the way to the bottom then the entire bottom can flex up and down. The bulkhead would only attach to the sides.
Some possible solutions.
Make bulkheads out of foam which can crush. We have damage but just not as much and we don't get water in the boat. My current boat has 2 foam bulkheads which go all the way to the floor. There are also 2 plywood bulkheads at each end of the boat where impact will not be as severe. Haven't take a big enough hit yet to damage any of them. Not all sheet foam is suitable for this.
Keep the bulkhead up off the floor by 2 inches and fill the space with a soft foam filler piece. Epoxy over the foam cells to keep water out then glue it in place with 3M5200 or 3M101. Now the floor can flex. If we take a hard hit right next to a bulkhead the bottom can flex upward instead of folding the material inward. I don't think it's reasonable to try to build a boat which can't be damaged. It's not worth the time or money. But maybe we can find some simple ways to lessen the damage to an amount which will allow us to float on and do the repairs in our shop instead of camp.
As for Kevlar, there has been an on-going debate about where Kevlar is best applied. Inside our out? Lets call it even and say we are going to use it inside and out. At any rate it is strong stuff but a bit harder to work with. The sky is the limit. At this point we are only constrained by cost. Honeycomb is available in polypropylene, aluminum, aramid, polycarbonate, stainless steel etc. Carbon fiber, while it is strong and light it is also brittle and will not work in our application other then possibley in sandwich construction here and there but, I haven't any spots on a dory where it makes sense at 50 dollars a yard.
The decked Tatman whitewater boat I mentioned is very solid but it is also very heavy. I believe I can build the same boat entirely out of plascore and drop the weight by 150 – 200 pounds (or 200 cans of Dale's pale Ale). Now that's motivation. Some people like heavy boats and feel they are more stable and less likely to flip. I do not share this view. To me lighter is always better if we can maintain strength and durability. About a framed boat. If we have frames which are strong as hell then the only thing a bulkhead does is support the deck and seal a chamber. It doesn't need to be ¼ or even 1/8 inch plywood. We could make it out of polypropylene sheet only a few mills thick. Then again get rid of the frames at the bulkhead locations and use a plywood or honeycomb bulkhead. We don't need both.
The whitewater boats made by Boulder where mentioned. While they have their place, the material is not something which will work in our 1 off construction. It's more of a factory material. It is also not practical in that it must go back to the factory for a patch. I have a plastic roto-molded boat which has a crack in it and nothing will close it. I have been able to keep water out of it using 3M5200. If I can't patch the boat on the river it's not for me.
The ideas are the same for wood or plascore. The materials work the same way and no lines are altered based on the material we chose. So this isn't really a statement of one material over another but rather getting the most flexibility out of whatever material we use.
This subject came up a here a week ago and I went back to some past discussions about the subject to put this together. I posted it here to see if others can add to the descussion and contribute some new ideas. Since famed construction has evolved to it's current state after many years of work it look to be mature. The boats running the Grand Canyon have proven their durability. The only change I can see would be to replace wood bottoms with newer composits. I don't see any other options with framed design.
This is a wood boat forum and wood boats are classic and nothing looks like them. If the desire is to build an all wood boat by all means do it. Tom's project of building a new version of Fulmer's GEM demonstrates how far we can go with wood construction and a 50 year old design still works. It will run the 100 rapids from Lee's Ferry to Lake Mead just like original did. We just need to keep in perspective what the materials can do. The last boat I completed was wood with a honeycomb bottom. I have lots of different hardwoods built into it. It needs to be oiled from time to time and that's ok. Painted honeycomb will never look like a handcrafted wood boat. What will I build next? Not sure, I just like to keep building but, I need to sell something to make room.
Looking for the views of other builder.
Larry
http://www.inskeepimages.com/g/highwaterdeso
People with GPS units on their boats have reported boat speeds through the rapid at over 20 MPH.
The dory images are of Linclon Frye, Ryan Pearl and Dave Inskeep. Each built the boat they are rowing. Ray Bloxham is running my boat which I built about 8 years ago.
Dave Inskeep runs a 16 foot all wood Tatman design modified for whitewater. The boat is over 10 years old, has run the Grand Canyon twice and has never had a hole in it. It makes it's third trip down the Grand next March.
We are not talking about fly fishing drift boats here. As we all know wooden drift boats are more then up to the task for class III water. We may need to fix a dig now and then but these boats will last a lifetime. However, I wouldn't advise running a Hyde or Tatman open fishing rig through Joe Hutch at 25000 or Lava at 10000 if you don't want it swamped and pinned on the rocks at the bottom of the river. This is not to imply there is anything wrong with either boat. I don't like fishing from my decked white water boat, the right tool as they say.
Who cares? Well, In the last 4 years I have been on 3 trips where there have been dories which could not continue until repairs were make. I also know of 3 other events on trips I was not able to make. All of this carnage happened to highly skilled boaters. It's just part of the deal. Being and old weak dude I look for the anti-carnage line whenever possible. One boater I know likes to say “go big or go home”. Well, he does and sometimes with a hole in his boat. We have fun and do what we can.
Lets try to apply some number to this. With the added weigh of bulkheads and decks let's say a 16 foot whitewater boat will be around 500 pounds. Add 2 adults, safely gear, cooler, food, camping equipment, water etc. Just call it 1000 pounds for a loaded boat. A large 17 foot Briggs boat will be more.
Now think about riding up a wave at 15 MPH and going down the back side into the trough and coming down onto a rock. 1000 pounds of force plus some added component with the boat moving downward. This isn't a math class (F=MA and all that stuff) so we will call it some number of pounds of force well above 1000 pounds. The rock is around 6 inches square or 36 square inches. 1000 pounds of boat and gear being dropped onto a 6 X 6 inch square. We also know from basic chemistry that liquids and solids are not compressible. So, when we hit the rock were does the 1500 pound impact energy go?
Options
We could crush the rock,,,,,, or not
The bottom of the boat could bend or not if we have bulkheads or frames.
If the rock doesn't crumble and the boat bottom can't bend then it will be the bottom of the boat which will brake. The energy will be converted into heat as it brakes the wood fibers and fiberglass as it folds inward.
How thick would the plywood and frames/bulkheads need to be to prevent this breakage? I don't know how thick it would be but it's too thick for a boat and the boat becomes 500 pounds heavier. If you want to build from wood that's fine but then you must live with the properties of the material and be willing to fix some things when you get pushed off line and take a big hit. There is no way around it and we have been doing just that for a long time.
What else can we do?
1 --
Make the bottom flexible. This sends some of the impact load to the surrounding material as it flexes. Like old time bridging of floor joist. Step on one floor joist and as it bends downward we send some of the load to the joist on each side of us. The impact now loads 200 square inches instead of 36. Unfortunately this is not an option when frames or bulkheads are being used.
2 --
make the bottom stronger so we can prevent the impact from braking the plywood by sending the load through more wood fibers to the material around the impact. Less psi on a bigger area to bring the load down to what the material can handle. Much thicker plywood. This would send the impact load down the fibers of the wood and with more plywood layers at some point the wood becomes strong enough not to brake if we make it think enough. This option is not practical beyond ½ inch plywood due to the added weight.
3--
Different materials.
Honeycomb, some of us have already started using this.
If you are building a wood white water boat the only option is to go with ½ inch plywood and cover it with kevlar which brakes at a much high load then glass fiber. I don't know of any other way. This will make a fine boat and over the years we will just need to fix it when we put a hole in the bottom. Not the end of the world. We pull the boat out of the river and thank the person who needs to mix up some epoxy for the patch for giving us a layover day. We can point to the fixes and toast the past which is nice. We can fix anything the river throws at us given enough time, beer and epoxy.
Now if we use ¾ or 1 inch honeycomb in place of the plywood we have a much lighter material since most of it is hollow. When the load of the impact is applied to the 6 X 6 inch area the inside of the honeycomb will start to deform dissipating much of the energy before it gets to the inside surface. If the impact load is high enough it will also brake the fiberglass on the outside as it crushes the honeycomb material just like with plywood. Now replace the fiberglass with Kevlar. Since the Kevlar is mush stronger then glass and does not want to stretch, the impact will try to stretch the fibers sending the load to a much larger area. This sends the impact energy into lets say 200 square inches of honeycomb taking away enough of the energy to prevent the rock from punching through. The thicker the honeycomb the more it can crush without getting all the way through and the kevlar sends the force to more of the honeycomb. Like stretching a trampoline over the outside of the boat so it can bounce off rocks.
Lets say the rock hits right next to the frame/bulkhead and the impact load is so high that the honeycomb just can't absorb it all. Then just like with plywood it folds inward and we have a hole in our boat. How could we stop this one? If we all agree that the honeycomb with kevlar is stronger then plywood what do we do now? What if the bottom could flex? What if the frames or bulkheads were not their? Then the entire bottom could bend inward sending the impact load to many square feet not just a few inches. Now we can take a much larger impact. How can we do this with a frame? I have no idea but we can do it with a bulk head. If the bulkhead does not go all the way to the bottom then the entire bottom can flex up and down. The bulkhead would only attach to the sides.
Some possible solutions.
Make bulkheads out of foam which can crush. We have damage but just not as much and we don't get water in the boat. My current boat has 2 foam bulkheads which go all the way to the floor. There are also 2 plywood bulkheads at each end of the boat where impact will not be as severe. Haven't take a big enough hit yet to damage any of them. Not all sheet foam is suitable for this.
Keep the bulkhead up off the floor by 2 inches and fill the space with a soft foam filler piece. Epoxy over the foam cells to keep water out then glue it in place with 3M5200 or 3M101. Now the floor can flex. If we take a hard hit right next to a bulkhead the bottom can flex upward instead of folding the material inward. I don't think it's reasonable to try to build a boat which can't be damaged. It's not worth the time or money. But maybe we can find some simple ways to lessen the damage to an amount which will allow us to float on and do the repairs in our shop instead of camp.
As for Kevlar, there has been an on-going debate about where Kevlar is best applied. Inside our out? Lets call it even and say we are going to use it inside and out. At any rate it is strong stuff but a bit harder to work with. The sky is the limit. At this point we are only constrained by cost. Honeycomb is available in polypropylene, aluminum, aramid, polycarbonate, stainless steel etc. Carbon fiber, while it is strong and light it is also brittle and will not work in our application other then possibley in sandwich construction here and there but, I haven't any spots on a dory where it makes sense at 50 dollars a yard.
The decked Tatman whitewater boat I mentioned is very solid but it is also very heavy. I believe I can build the same boat entirely out of plascore and drop the weight by 150 – 200 pounds (or 200 cans of Dale's pale Ale). Now that's motivation. Some people like heavy boats and feel they are more stable and less likely to flip. I do not share this view. To me lighter is always better if we can maintain strength and durability. About a framed boat. If we have frames which are strong as hell then the only thing a bulkhead does is support the deck and seal a chamber. It doesn't need to be ¼ or even 1/8 inch plywood. We could make it out of polypropylene sheet only a few mills thick. Then again get rid of the frames at the bulkhead locations and use a plywood or honeycomb bulkhead. We don't need both.
The whitewater boats made by Boulder where mentioned. While they have their place, the material is not something which will work in our 1 off construction. It's more of a factory material. It is also not practical in that it must go back to the factory for a patch. I have a plastic roto-molded boat which has a crack in it and nothing will close it. I have been able to keep water out of it using 3M5200. If I can't patch the boat on the river it's not for me.
The ideas are the same for wood or plascore. The materials work the same way and no lines are altered based on the material we chose. So this isn't really a statement of one material over another but rather getting the most flexibility out of whatever material we use.
This subject came up a here a week ago and I went back to some past discussions about the subject to put this together. I posted it here to see if others can add to the descussion and contribute some new ideas. Since famed construction has evolved to it's current state after many years of work it look to be mature. The boats running the Grand Canyon have proven their durability. The only change I can see would be to replace wood bottoms with newer composits. I don't see any other options with framed design.
This is a wood boat forum and wood boats are classic and nothing looks like them. If the desire is to build an all wood boat by all means do it. Tom's project of building a new version of Fulmer's GEM demonstrates how far we can go with wood construction and a 50 year old design still works. It will run the 100 rapids from Lee's Ferry to Lake Mead just like original did. We just need to keep in perspective what the materials can do. The last boat I completed was wood with a honeycomb bottom. I have lots of different hardwoods built into it. It needs to be oiled from time to time and that's ok. Painted honeycomb will never look like a handcrafted wood boat. What will I build next? Not sure, I just like to keep building but, I need to sell something to make room.
Looking for the views of other builder.
Larry
Views: 585
Replies to This Discussion
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Permalink Reply by Jimmy Emery on
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You've covered a lot in this post. Like my previous post explained, I have been struggling over whether of not to install bulkheads. It seems logical to me that the more flex the better. When I started building my boat I jumped in with both feet started buying materials with out doing my research. In retrospect I would have gone with honeycomb bottom, buy I'm stuck with the 3/8". So how can i not spend my river trips on the water and not on the beach pissing everyone off waiting for epoxy to dry? I think a deck supported with a ledger, and some two by material to stiffen everything up might be the way to go. I was planning on a self bailing cockpit that will hang from the deck. Maybe one bulk head in the rear big enough to keep the boat from sinking if it ever does get a hole in it.
I have no idea if any of this is going to work like it does in my mind.
- Jimmy
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Permalink Reply by lhedrick on
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I would certainly recommend bulkheads just to contain water to one compartment when the day comes that you put a hole in the boat. You could always use foam sheet just to close off areas.
My rowers area doesn't bail as fast as I would like and being 6 foot 3 I would like the foot well to be lower which would make the bailing even worse. Next time I will use a pump and 2 small SLA batteries mounted under the deck.
A 3/8 bottom is a bit weak for high speed impact. Build up the inside chine fillet larger then normal and cover with heavy bi-axial tape to make it stronger. I use 2 layer inside and out. I would also put kevlar on the bottom to make it tougher.
If you have not painted yet I would also add a rub strip 3 inches above the water line like you see on many of the farmed boats posted here. I saw one boat hit a wall in West Water and it cracked the side behind the rower. The extra bulk may have limited the damage.
L
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Permalink Reply by Jeff Peak on
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Larry, I support you in your bid to build an indestructible whitewater dory.
however, at the risk of sounding closed minded, i think your energy is better spent staying off of rocks, than engineering a boat that can withstand said rock and the crushing pressure it can/will deliver. I think only rafts can withstand that kind of blunt force. maybe an aluminum hard hull, but never wood.
having said that, I anxiously anticipate my first big hit. it will hurt, and there will be repairs. taking hits (minimizing hits) is part of taking wood boats down big water. As they say, "you're always above Lava".
I'm not calling him out, but I'd love to hear what andy Hutchinson had to say, seeing as he is at the front of this.
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Permalink Reply by Jon Carter on
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Larry I am older and weaker than you I'm sure but what that also means is that my boating experience goes back further in history - when I was a young whitewater freak and into kayaks we built the bottom half of the boat out of kevlar and the top half out of "S" glass so that the top would break away if trapped. The important point here is that we didn't build out of kevlar both top and bottom because the kevlar wouldn't break away and would trap the boater.
Why not build the bottom with foam for to deal with the weight issue but put a layer or two of kevlar on both the top and bottom of the foam. Seems like the bottom would now take more than a rower could with stand and not end up holed. There must be some reason I don't know so enlighten me - I do know that I still have a kayak built the way described and I have had to repair the top and the frame the seat sets in but have never holed the kevlar half. The boat is now over 30 years old and I keep it around just to give me an excuse to talk about the great old days to my sons. Tongue in cheek but a grain of truth I suppose. We also built our kayak blades from layers of kevlar.
Just my thoughts - Jon
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Jon,
I am trying to get my head around a seam which can brake away. I'm not a kayaker. At 6 foot 3 I look at the new kayaks and I can't understand how anyone can get into one of those things. We had 3 on our last Grand Canyon trip. After floating past Lava, we didn't see the kayakers for hours. They played at lava until almost dark. They were so tired they ate dinner and then were out until the next morning.
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It think there are lots of possibilities for foam. My bulkheads are made of foam sheet insulation. So far so good but, it was just an experiment. Fiberglass and epoxy will just peal off so it's not really the way to go. A friend made his bulkheads from foam also but the foam he used bonded very well with fiberglass cloth. His boat is a Rogue design. He is a young high energy boater and has already punched holes through the wood sides and honeycomb kevlar bottom and chine on 2 different trips. Each time it's been patched up and it's ready for more action.
From the work I have done with foam and honeycomb I don't think I would use foam for a bottom but, I do think it's a workable idea. I have built test pieces from plascore Kevlar and fiber glass and smashed them with hammers and rocks. In most cases things just bounce off. I think wood is just a strong but it's heavier and is clearly more brittle. Same for carbon. Carbon is great until it brakes but when it does it brakes big time and it's 50 dollars a yard.
There is a lot of misinformation about all this boating stuff. While talking with a bunch of the guides over on the Green. They all shy away from wood boats. Those who do run them are usually builders. If they buy a boat it's usually molded polyester resin and glass. They are mostly running Hydes, Clackas and now the plastic Boulder boats. In my view Boulder is way ahead of the other commercial builders but 10000 is a bit much. Commercial builders need to mass sell product at a price point to be profitable but I don't like some of the bad information they spread around. This won't be popular with folks but, there is no way in hell a builder of a molded fiberglass boat can build anything even close to what we wood builders are building. It's kind of like comparing a custom spots car to a Ford F250. I understand guides don't want to fool around with varnish but, my decked boat is painted. I don't do anything to it other then oil the ash gunwales now and then. So first hand experience tells me wood is no more maintenance than any other material and the commercial companies are not exactly honest but, I guess that's just business.
I doubt I will ever use plywood on a boat bottom ever again. I see modern drift boats and dories being constructed from both wood and composite materials.
Having been on the water with Jeff I think the idea of staying off the rocks is a bit easier for him them for many of us. As a rower I am about as skilled as I am ever going to get. I take the easy lines when ever I can but at Granite and Lava there aren't many options. Screw up and you are going to pay. On some of those runs I count on a little luck coming my way each time. So far I have lucked out. Sooner or later though that first hole is going to happen. Should those of us who are not top rowers stay home? Hell no, it's too much fun no matter how bad I am at the oars. I don't see this as an issue of building an indestructible boat but, rather finding out how to get the most out of whatever materials we use.
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Permalink Reply by Randy Dersham on
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I agree with Larry on the building methods vs performance and the comments about misinformation from other commercial builders. Usually this comes from trying to make a marketing pitch for a feature rather than talking about performance being equal to a builders decisions about design and materials which define that performance and at the same time create the compromises inherent in those decisions. Marketers don't like compromises.
Larry, what thickness of honeycomb bottom are you using. What is the weight difference vs 1/2 plywood?
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Permalink Reply by eric stevens on
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Have you ever tried building the sides out of honeycomb? I was thinking about building my next boat with honeycomb for the bottom and sides and then useing wood on the rails and for seats to make it look nice. What does it cost for a sheet of the honeycomb plascore? I was also wondering, why not make the bulkheads out of it too?
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I hope to build my next boat out of all plascore. I will use wood for the gunwales, stem and a few other items. I will use it for bulkheads from now on also. The only issue for the sides will be to close off the cells at the top edge. A slot can be routed in the edge so a T shaped type of molding can be epoxied into place. The gunwale stock could also extend 1/4 about the side panel and then filled with epoxy which will bond it to the wood stock.
As for weight, 3/4 stock is about 7 Oz. per square foot. 21 pounds for a 4 X 8 sheet. Much of the weight are the top and bottom surface sheets so going from 1/2 to 3/4 doesn't add that much. I use 3/4 inch on the bottoms of fishing boat. My next white water boat I may move up to 1 inch on the bottom. The thicker the core the more energy it can dissipate and the extra 1/4 inch in the core adds very little weight. On the sides 1/2 looks like the size.
Shipping is a problem if there is no distributor in your area. But, thats the same with plywood. I paid about 100 dollars for 5 X 10, 3/4 inch sheets with shipping. I got 16 sheets on my last order.
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Larry,
I'm interested in what you think of the rigid foam bulk heads you've put in your boat. How has it held up, how did you attach them, would you do it again???
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I have never hit anything so it's still an experiment. I used the same type of foam for bulkheads in my sea kayaks. They are covered with 6 Oz glass. After placing them in the boat they were epoxied in place with 2 inch glass tape. It's been 3 years now everything is still as it was. I will look and see if I still have any images of the inside layout before the deck was installed.
A friend used some type of black closed cell foam on his boat. It is a much better choice because epoxy bonded to it much better. If you try to peal off the fiber glass it won't come off.
The only issue I have with the boat is the hatch lids. They are plywood with oak frames on the outside edge. The oak has warped a bit.
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Permalink Reply by Herb Jacobsen on
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I am sorry but this discussion is way too complicated. The bottom line in any drift boat situation is to "not hit rocks". Granted you won't miss all of them but trying to build a boat that is "bullet proof" is a waste of time and energy. Have I hit rocks? You bet, some that would make your teeth rattle. Has the boat been infiltrated? Yes when it was hit on the side in a back eddy. Sharp rocks and 1/4" ply do not go together. A few minutes to dry it out, some 100 mph tape and on the road again.....
I have run a lot of class IV and almost class V in an open drift boat and have never had a problem. There is a point where you have to take a look at the rapid and decide whether is is easier to line the boat rather than run it. Sure we all get the thrill from the "BIG WATER" but you also have to use a little sense. You do not have to be going 15 mph in a rapid if you do not want to. That is what the oars are for some times. They help to slow you down.
Wood boats break from time to time. That is just the way things happen. It really is not rocket science....... I watched a wood boat get blown apart in the lining channel at Rainie Falls on the Rogue. It got sideways and before it could be brought back around it tipped up and blew apart. Boats have a lot of structural integrity going inward not outward....
Bottom line is build a good wood boat and learn how to row it properly..... Do not be fooled by design and material innovations when the fore runners of our industry did not have all the things we have today. Yet somehow they managed to get down the rivers we all so love......
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Where is the complex part?
The term "bullet proof" has never been mentioned. Where did that comment come from?
Trying to prevent damage is viewed as a "waste of time". There is no challenge in new ideas?
Why not go back to plank construction? Perhaps we could use hide glue again. Why did we leave the purple resourcinol glue behind?
If you could hit a rock and not have to stop to bail the water out would you prefer to not use new materials and fix a hole just before dark?
Am I to believe I would be better of with my old 45 pound steel bike instead of my current 20 pound titanium ride.
100 mph tape wouldn't have fixed some of the holes I have seen in the last few years. Is it better to just keep putting holes in the boat?
Are we to just assume "those people" have no business on the river since they can't row? Kind of like those people who row with oar rites. They should stay home.
I am an average rower at best but, I have seen some very skilled people flip boats.
Since a person doesn't know how to row a boat properly when they are starting out, how do they learn how to row it properly?
If it was possible to prevent a boat from blowing apart as you describe, you would still prefer to build one which would blow apart?
What's the point of a forum if not to discuss ideas?
I guess I just don't quite understand your position.
I am fine with all those who wish to row big water in a canvass covered wood frame boat but, I will pass.
We are not talking about carbon fiber jet planes. This a dory we are talking about which, has no curved cuts on any surface other then the bottom panel.
So, where is the complicated part? Pass pile A and go to pile B to get different material which is still 4X8. I guess I don't get it.
I kind of get it in that I was a software engineer for 25 years and I now hate the stuff. Just trying to understand what I'm missing.
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