My personal preference would be to go with thinner wood, and add some bracing or reinforcements where use indicated it was needed. I just dislike thick plywood.
help lightest boat you can build
- Thread starter tx river rat
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Thinking out loud here. How about 1/8" wood with all coats of epoxy made with varying percentages of those lightweight microballons. Could possibly cut down the total weight of epoxy by half. Also, paying minute attention to the fairness and the finish of the hull could pay more dividends than most any material choice would. Lots of long board sanding could really pay off.
Bigger paddle blades are more efficient at transferring power if the paddler is up to the task. Less motion wasted to smaller blades letting water slip past the sides.
Bigger paddle blades are more efficient at transferring power if the paddler is up to the task. Less motion wasted to smaller blades letting water slip past the sides.
I go back to this site often to take in some of the theory of design. This is what John Winters has to say about hull smoothness vs design . http://www.greenval.com/jwinters.html
"The great disappointment for the designer is that, after reducing friction(through design-my addition) to a minimum, the paddler is unlikely to notice the effect. A 5 percent decrease in wetted surface is worth bragging about, but a single year's scratching and banging can easily DOUBLE Cf (coeficient of friction- or frictional resistance) from 0.004 on a new fiberglass canoe to 0.008. This more than offsets the designer's efforts. The cavalier attitudes of most canoeists towards their boats is evidence that a 50 percent resistance increase is not often noticed if only because the onset of its effect is so gradual. "
So an extra couple of hours of fairing and sanding along with taking care not to scuff up and scratch your boat's bottom offers as much or more advantage than the best design features of a professional.
Joey
"The great disappointment for the designer is that, after reducing friction(through design-my addition) to a minimum, the paddler is unlikely to notice the effect. A 5 percent decrease in wetted surface is worth bragging about, but a single year's scratching and banging can easily DOUBLE Cf (coeficient of friction- or frictional resistance) from 0.004 on a new fiberglass canoe to 0.008. This more than offsets the designer's efforts. The cavalier attitudes of most canoeists towards their boats is evidence that a 50 percent resistance increase is not often noticed if only because the onset of its effect is so gradual. "
So an extra couple of hours of fairing and sanding along with taking care not to scuff up and scratch your boat's bottom offers as much or more advantage than the best design features of a professional.
Joey
jdupre' said:Thinking out loud here. How about 1/8" wood with all coats of epoxy made with varying percentages of those lightweight microballons. Could possibly cut down the total weight of epoxy by half. Also, paying minute attention to the fairness and the finish of the hull could pay more dividends than most any material choice would. Lots of long board sanding could really pay off.
.
Definitely the microballons in the fillets between strips and seams. Saves a lot of epoxy and reduces the weight. Also makes any sanding of the fillets a lot easier.
Not a good idea but I have done it....... Glass the outside and epoxy saturate the inside , then glass the middle half of the boat where you would be but not a quarter of each end. As far as the deck , epoxy saturate it , sand and do one more coat of epoxy. Just don't stand on the deck after the boat is made. :wink:
If you wanted to glass the desk to make sure it was sealed to the hull on the outside then use some 2oz glass with the underside just epoxy saturated.
I think the 1/8 wood cut into strips would be a waste of time since when the strips are put back together you end up with what you started with , a 1/8 inch thick board. Unless you are doing it to round the boat out or for aesthetic ( good looks ) reasons.
Chuck.
One more thought. Use really light 1/8" (or less :shock: ) wood strips and do not run them continuously. I envision say a 3 foot long strip and then leave a space of a foot. Stagger these empty spaces about the panels so they don't line up. Cover with light weight cloth and epoxy. You would, in effect , have a honeycomb structure that would be quite a bit lighter and almost as strong as solid wood. After all, a fishing rod and a kayak paddle have air for a core.
Joey
Joey
How about a Balsa Wood basket weave?
1/16 inch sheets cut into strips then basket wove into a 4x8 sheet and epoxy saturated then cut?
Or weave a single panel the width and length of the side Laker panels such as a side 2ft. by 13ft. creating a no spice panel.
http://www.balsawoodinc.com/balsawoodsheets
delete if needed
1/16 inch sheets cut into strips then basket wove into a 4x8 sheet and epoxy saturated then cut?
Or weave a single panel the width and length of the side Laker panels such as a side 2ft. by 13ft. creating a no spice panel.
http://www.balsawoodinc.com/balsawoodsheets
delete if needed
Dry balsa, as started by the Aussie who built of it, is pretty delicate stuff to work with. When finally encapsulated with glass and epoxy, it would be OK, but the primary benefits of the boat would be: 1. that you were able to build such a thing, and 2. you could stand around in supermarket parking lots holding a boat up in the air with ease.
There's a reason why good plywood has become a standard for wooden boats, actually, several reasons. It works in the finished product; that is, it will withstand abuse and still come through. It is easy to work with as a building material. Also, it looks very nice when completed.
There's a reason why good plywood has become a standard for wooden boats, actually, several reasons. It works in the finished product; that is, it will withstand abuse and still come through. It is easy to work with as a building material. Also, it looks very nice when completed.
Just for reference balsa verses birch
balsa
http://www.matbase.com/material/wood/cl ... properties
birch
http://www.matbase.com/material/wood/cl ... properties
balsa
http://www.matbase.com/material/wood/cl ... properties
birch
http://www.matbase.com/material/wood/cl ... properties
How about you just build a boat out of 1/4" ply the way you normally would.
Once the boat is complete and prior to the glass and epoxy, Drill say two inch holes out of the entire boat. Leave an inch between holes.
Then glass. You would loose 75% of the weight bt the structure would still be in place.
It would look awesome also.
You could just drill fewer holes where you need strength, like the seat area.
Once the boat is complete and prior to the glass and epoxy, Drill say two inch holes out of the entire boat. Leave an inch between holes.
Then glass. You would loose 75% of the weight bt the structure would still be in place.
It would look awesome also.
You could just drill fewer holes where you need strength, like the seat area.
Unlike someone else ... My dream for a long time is to make a canoe out of the Balsa ( as a filler material ) since I enjoy making light weight boats. I have made a lot of model airplanes from it with a silk covering that flew and lasted a long time.
I want to thank the folks for offering the information on the Balsa Wood and it would be interesting to see just how light a 14 or 15 canoe can be made from it. Right now my one canoe is 30 pounds with a 2 pound seat in it , the Sasquatch 14 x 30 from JEM Watercraft.
Plus , before then , a UJ Pirogue , the full length ( 15 1/2 ) at 32 pounds with another 2 pound seat in it.
My thoughts all along is that the filler is the middle of the sandwich and the bread is what you put on the outside of that filler..... Plus Balsa is a wood. The commercial canoes are made from all glass and most of them have a reinforcing strip ( Keel ) but the center of the boat is only 1/8 th of an inch thick. :roll:
If I make a canoe like that and it comes out in the low weight , all the better in fact I would say ...... HOT DAM.
Not suggesting that anyone does that without some time and funds to kill and a little experience in making wood boats with epoxy and fiberglass. Plus there is one consideration , I do not abuse my boats , if anything I baby them when I use them and avoid hazards that might cause problems.
Chuck.
I want to thank the folks for offering the information on the Balsa Wood and it would be interesting to see just how light a 14 or 15 canoe can be made from it. Right now my one canoe is 30 pounds with a 2 pound seat in it , the Sasquatch 14 x 30 from JEM Watercraft.
Plus , before then , a UJ Pirogue , the full length ( 15 1/2 ) at 32 pounds with another 2 pound seat in it.
My thoughts all along is that the filler is the middle of the sandwich and the bread is what you put on the outside of that filler..... Plus Balsa is a wood. The commercial canoes are made from all glass and most of them have a reinforcing strip ( Keel ) but the center of the boat is only 1/8 th of an inch thick. :roll:
If I make a canoe like that and it comes out in the low weight , all the better in fact I would say ...... HOT DAM.
Not suggesting that anyone does that without some time and funds to kill and a little experience in making wood boats with epoxy and fiberglass. Plus there is one consideration , I do not abuse my boats , if anything I baby them when I use them and avoid hazards that might cause problems.
Chuck.
"A well scratched boat is a well loved boat." Mine are working tools of the trade. One of the reasons I choose good wood.
tx river rat said:Chuck
Thats the way I am I really BABY my boats :shock: :shock: :shock:
Ron
Yeah, right. BANG! CRAAAAACCKKK! SCRAAAAAAAPPPEE! SCRRREEEEEEEECHHH!
:mrgreen:
My thinking behind the 1/8 strips is this. My duck is a full 1/4 of an inch thick ,mostly white pine ,now it is lighter stiffer
than the 3/16 ply I built my other boats from. You should be able to strip build it just like I did the duck but use 1/8. then instead of just a saturation coats ,pre coat it and apply the cloth while your precoat is wet.use 2 ounce glass on the outside 1.5 on the inside.
I have a test panel I am fixing to glue up out of western red ceder done like that.
I also have some balsa strips coming for a test.
A twenty lb ugly duck whee now that is something to think about.
Ron
than the 3/16 ply I built my other boats from. You should be able to strip build it just like I did the duck but use 1/8. then instead of just a saturation coats ,pre coat it and apply the cloth while your precoat is wet.use 2 ounce glass on the outside 1.5 on the inside.
I have a test panel I am fixing to glue up out of western red ceder done like that.
I also have some balsa strips coming for a test.
A twenty lb ugly duck whee now that is something to think about.
Ron
oldsparkey said:How about posting the rules for making the boat ....... All of them so we can have a good idea of what they are looking for.....
tx river rat said:News flash they dropped the race it will be judged 40 % on service ability and 60 percent on weight.
john the pom said:If'n you're gonna get real nitty gritty on this then the first question has to be is there a min/max weight of paddler?
We still don't know just what the rules call for and how are they going to judge serviceability? Something along the lines of Steve's lightweight glass covered Kraft paper is likely to be lightest, the extra thickness of a material like balsa would add some strength. If Kraft paper isn't allowed then use sheets of glass covered veneer with extra layers or plywood under the cockpit. The bulkheads will form part of the frame, other frame pieces could be of glass covered balsa or cedar strips.oldsparkey said:If it is not a long time boat but a disposable one ........
Jimmy
It has to be a wood composit boat and be judged bye a panel as a serviceable boat.
My aim in this is not to build a throw away boat but one that can be used. So it will be a wood core of some kind.
The rules are getting put together right now and I will let you know as soon as they are hard and fast.
Ron
My aim in this is not to build a throw away boat but one that can be used. So it will be a wood core of some kind.
The rules are getting put together right now and I will let you know as soon as they are hard and fast.
Ron
tx river rat said:It has to be a wood composit boat and be judged bye a panel as a serviceable boat.
My aim in this is not to build a throw away boat but one that can be used. So it will be a wood core of some kind.
I guess this means you are doing it for fun and not to win, this makes a big difference in advice. The throw away boats will be the lightest as durability is low on the priority list.
I personally would consider a balsa based skin on frame but that would be a throw away. The balsa stripper seems interesting, don't know if I'd go as low as 1/8" but you could build a usable fairly durable boat that would probably come in under 20lbs using 2 oz cloth or even less weight cloth. Nice thing about that is that after the competition you could add more heavier cloth and have a boat that will last a lifetime.
Don't under estimate the abilities of balsa, properly structured it can be incredibly strong. Balsa based RC aircraft go thru incredible forces and can last for years
just for interest....most of the competitions like this that I've seen have a rule of "no multi part adhesives". Makes it much more challenging when epoxy cannot be used
Belly
What makes this contest so unique is the lightest boat probably want win,so yea trying to win it is part of my goal.
with 40% of the score on servicability ,and 60% on weight a balanced building plan will serve you the best.
It has to be wood core,fiberglass cloth,(no kelvar are exotic clothes) and as far as the paddlers weight ,that want figure in.
The whole ideal of this contest is to come up with techniques and ideals for a good sea worthy light craft. Not just the lightest.
Ron
What makes this contest so unique is the lightest boat probably want win,so yea trying to win it is part of my goal.
with 40% of the score on servicability ,and 60% on weight a balanced building plan will serve you the best.
It has to be wood core,fiberglass cloth,(no kelvar are exotic clothes) and as far as the paddlers weight ,that want figure in.
The whole ideal of this contest is to come up with techniques and ideals for a good sea worthy light craft. Not just the lightest.
Ron