Hollow wooden kneeboard
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wolruss
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Very impressed with not only the project but also the documentation,
excellent job Tomway.
All the input from various parts of our kneeboard world was equally impressive - a lot of knowledgeable people out there - leaves people like me who just rides and enjoys them, in awe of those who figure it all out and put it all into action, especially in different materials such as you have used, love the artwork too
Thanks for the experience guys
Cheers Wolruss
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Sprocky
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That's an insane job you've done, Tomway. Really inspiring. I don't have easy access to beautiful tropical hardwoods, but I'm only three blocks from a Home Depot (I guess the Oz/Kiwi equivalent would be Bunnings Warehouse). I wonder what I could put together with the supplies they offer... 
Why do Moroccan tree climbing goats make great pets?
a. They'll mow, and fertilize, your lawn.
b. They can climb trees!
c. Goat's milk, cheese, yogurt, etc is pretty tasty
d. The goats themselves are pretty tasty.
e. All of the above
a. They'll mow, and fertilize, your lawn.
b. They can climb trees!
c. Goat's milk, cheese, yogurt, etc is pretty tasty
d. The goats themselves are pretty tasty.
e. All of the above
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tomway
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Cheers everyone, yep, I'm really stoked with it all in all! It's amped me into putting the finishing touches into the sister board. Just need to make some fins for it.
Sprocky - reckon you could do a great job with home-depot wood. You've probably got access to stock sizes that are pre-finished which cuts out about 75% of the hassle. Some of the bits of wood I used were straight from a log and needed drying etc. first. Also you've probably got access to cork (used for flooring) which is light, buoyant and easy to lay up in your rails. Be great if some other kneeriders tried making this kind of board to compare ideas.
Well , here's some final notes on the riding.
Buoyancy.
The final weight, glassed, glossed and polished came back at 5.5kgs / 12 pounds. By no means a light weight. Still a bit suprised that 1 layer of 4oz and a gloss added 2 kgs ??!! Seems a bit excessive. However, in the water the board felt LIGHTER than my PU fish. With the hollowed out rails it was super buoyant and floated me higher in the water. But there is a problem associated with this and I think it reflects a design consideration for all hollow boards.
The buoyancy was extremely 'pushy' under the ribs (when prone) and under the knees when riding. In comparison the tail sank much more readily. It kind of felt like a pendulum around the knees and was a bit odd. Looking back, I think I know whats happening. I copied the foil from my PU fish. But air is much more buoyant than foam, so though the volume distribution between the centre of the board and the tail is similar, the buoyancy distribution is not. A few cc's of air makes a huge buoyancy difference in comparison to a few cc's of foam. This definitely effected handling negatively. Turning in the traditional fish weight forward position was very difficult and the board felt tracky and reluctant. Most of the time in turns I was sitting back on my ankles which didn't allow for the kind of drive I would have liked. In part I think this could be corrected by moving the fins forward, but the real problem lies in the volume distribution. Perhaps thinner/pinchier rails would help here too?
...which leads to fins. I don't feel the 'canard' quad setup works well on a kneeboard. this could be because I made them myself and maybe screwed them up, but crox had similar feelings when using the pavel speed dialers on his 'proper' board (look at his uk forum post). The sister board will get a more normal quad set up with big fin/small fin hierarchy from front to back.
Flex. The board didn't flex nearly as much as I'd hoped. Before glassing it did, it had a real positive twing-twang to it. PU resin and a thick gloss coat stiffened it up a lot. Also, as previously mentioned, because of the buoyancy distribution problem I never really got a chance to put it on it's rail and wind it up. But the board did feel 'alive', especially in ....
...Trim. It was very very fast and joyful! Minor adjustments in wave position and small turns were met with bursts of speed. No bogging or sluggishness on this board! Though I didn't experience the kind of rail flex-return I was hoping for, every inch of the board felt alive in trim, each wooden part taught and aware, flexing and returning continuously with each adjustment. Not only can you feel the board below you but you can hear all the little bumps and nuances of waves curvature passing under the tight skins. Every wave was a sensorary delight and made me smile ... a lot
So my improvement list for next time:
1. Less pronounced foil. More parallel volume distribution from centre to tail.
2. No Canard quad setup. Keels or normal quad setup.
3. No gloss. Use epoxy if I can find some.
Tom
Sprocky - reckon you could do a great job with home-depot wood. You've probably got access to stock sizes that are pre-finished which cuts out about 75% of the hassle. Some of the bits of wood I used were straight from a log and needed drying etc. first. Also you've probably got access to cork (used for flooring) which is light, buoyant and easy to lay up in your rails. Be great if some other kneeriders tried making this kind of board to compare ideas.
Well , here's some final notes on the riding.
Buoyancy.
The final weight, glassed, glossed and polished came back at 5.5kgs / 12 pounds. By no means a light weight. Still a bit suprised that 1 layer of 4oz and a gloss added 2 kgs ??!! Seems a bit excessive. However, in the water the board felt LIGHTER than my PU fish. With the hollowed out rails it was super buoyant and floated me higher in the water. But there is a problem associated with this and I think it reflects a design consideration for all hollow boards.
The buoyancy was extremely 'pushy' under the ribs (when prone) and under the knees when riding. In comparison the tail sank much more readily. It kind of felt like a pendulum around the knees and was a bit odd. Looking back, I think I know whats happening. I copied the foil from my PU fish. But air is much more buoyant than foam, so though the volume distribution between the centre of the board and the tail is similar, the buoyancy distribution is not. A few cc's of air makes a huge buoyancy difference in comparison to a few cc's of foam. This definitely effected handling negatively. Turning in the traditional fish weight forward position was very difficult and the board felt tracky and reluctant. Most of the time in turns I was sitting back on my ankles which didn't allow for the kind of drive I would have liked. In part I think this could be corrected by moving the fins forward, but the real problem lies in the volume distribution. Perhaps thinner/pinchier rails would help here too?
...which leads to fins. I don't feel the 'canard' quad setup works well on a kneeboard. this could be because I made them myself and maybe screwed them up, but crox had similar feelings when using the pavel speed dialers on his 'proper' board (look at his uk forum post). The sister board will get a more normal quad set up with big fin/small fin hierarchy from front to back.
Flex. The board didn't flex nearly as much as I'd hoped. Before glassing it did, it had a real positive twing-twang to it. PU resin and a thick gloss coat stiffened it up a lot. Also, as previously mentioned, because of the buoyancy distribution problem I never really got a chance to put it on it's rail and wind it up. But the board did feel 'alive', especially in ....
...Trim. It was very very fast and joyful! Minor adjustments in wave position and small turns were met with bursts of speed. No bogging or sluggishness on this board! Though I didn't experience the kind of rail flex-return I was hoping for, every inch of the board felt alive in trim, each wooden part taught and aware, flexing and returning continuously with each adjustment. Not only can you feel the board below you but you can hear all the little bumps and nuances of waves curvature passing under the tight skins. Every wave was a sensorary delight and made me smile ... a lot
So my improvement list for next time:
1. Less pronounced foil. More parallel volume distribution from centre to tail.
2. No Canard quad setup. Keels or normal quad setup.
3. No gloss. Use epoxy if I can find some.
Tom
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Jon Manss
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Now that is good feed back Tom. It sounds like you are a little stiff in your rocker. Did you have any V in the tail? You also mention the bouyancy delema, and how could you know without trying. I think you have a handle on this. You might want to go with a more uniform thickness all the way to the tail to add more punch behind your knees. I know you are already on to this. The other thing that might help is fins that are as thin as a foamy. Thick fins tend to draw out diffirent tracks. Your fins might be miss leading you on your first board designs ability. In my opinion from far away and with little knowledge of what is working and what is not, you have made the first step to realy making a viable hollow board. Take that next step to adjust a few things and see what happens. Word of caution too many changes cloud the issue as to what is working and what is not. How old are you?
there's an update on some fine Tomway boards and others here:
http://kneeboardsurfing.co.uk/forum/YaB ... 180086/8#8
for those with enquiring minds.
Well worth a look if you admire fine craftsmanship!
http://kneeboardsurfing.co.uk/forum/YaB ... 180086/8#8
for those with enquiring minds.
Well worth a look if you admire fine craftsmanship!
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Mike Fernandez
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Wow, I just read all five pages, what a great thread! Tomway I am so happy for you, man you must be proud of building that beauty, and seeing that it works! Man, I got tingles reading this thread, and seeing the final rides 
I am a traveller of both time and space, a weaver in and out of dreams, I see worlds seldom seen.
www.michaelfernandezphoto.com
Rocky Point/Black Rock
http://www.youtube.com/user/kneelocoveproduction
www.michaelfernandezphoto.com
Rocky Point/Black Rock
http://www.youtube.com/user/kneelocoveproduction
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bigtreeman
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to address some of your issues
Hi Tom,
I just noticed your posts on your woody. Here are some of the methods I've used for my construction.
I cut my frames from ply leaving rectangles of ply which define the frame height to hold the rocker during construction. I cut the frames using a cnc router and the bit matches the skin thickness. This creates an outer frame as used in some boat construction and holds the skin to the frames for gluing and reduces the number of clamps needed. Make a supporting table/frame.
The outer frames can be slid on and off around the finished board and could be used for packaging/protection for shipping.
I don't use stringers. I use a wood bending iron to pre-bend the rocker into the wood slats for deck, edges and bottom. I have noticed many woodies end up rather flat.
I make a block of support frames in the knee area, a honeycomb of 100mm squares.
I have an S deck with lots of buoyancy at the middle and back and thin nose, your fish might have been more suited for foot surfers, makes it perfect for duck diving as well.
I use teak plugs with grub screws and a block between two frames.
All gluing is with epoxy resin designed for wood, don't use urethane glue or titebond III.
This is for light planes and applies well to surfboards -
http://www.recreationalflying.com/tutor ... tchbuilder
My current board has no glass. The top is finished with tung oil which has to be re-applied annually or so, the bottom and rails have epoxy resin painted with urethane paint. I don't like the resin/paint. Finished the deck by draw filing lengthwise with a rasp edge to groove the surface, then sanding with wet and dry, finishing with 600 and tung oil.
I have tried gortex breathing plugs but they eventually clog with salt and sand. I have a screw plug which must be removed for storage, even leaving on the beach in the sun for a short time, air pressure builds really fast. The skin will separate from the frames or worse crack the skin.
In future I'll make my shell 10mm thick paulonia and a flexible pine strips for the rails, with Cutek timber coating www.timbercoatings.com.au .
My current board is a few years old, I gave away my last plastic board a couple of years ago.
I just noticed your posts on your woody. Here are some of the methods I've used for my construction.
I cut my frames from ply leaving rectangles of ply which define the frame height to hold the rocker during construction. I cut the frames using a cnc router and the bit matches the skin thickness. This creates an outer frame as used in some boat construction and holds the skin to the frames for gluing and reduces the number of clamps needed. Make a supporting table/frame.
The outer frames can be slid on and off around the finished board and could be used for packaging/protection for shipping.
I don't use stringers. I use a wood bending iron to pre-bend the rocker into the wood slats for deck, edges and bottom. I have noticed many woodies end up rather flat.
I make a block of support frames in the knee area, a honeycomb of 100mm squares.
I have an S deck with lots of buoyancy at the middle and back and thin nose, your fish might have been more suited for foot surfers, makes it perfect for duck diving as well.
I use teak plugs with grub screws and a block between two frames.
All gluing is with epoxy resin designed for wood, don't use urethane glue or titebond III.
This is for light planes and applies well to surfboards -
http://www.recreationalflying.com/tutor ... tchbuilder
My current board has no glass. The top is finished with tung oil which has to be re-applied annually or so, the bottom and rails have epoxy resin painted with urethane paint. I don't like the resin/paint. Finished the deck by draw filing lengthwise with a rasp edge to groove the surface, then sanding with wet and dry, finishing with 600 and tung oil.
I have tried gortex breathing plugs but they eventually clog with salt and sand. I have a screw plug which must be removed for storage, even leaving on the beach in the sun for a short time, air pressure builds really fast. The skin will separate from the frames or worse crack the skin.
In future I'll make my shell 10mm thick paulonia and a flexible pine strips for the rails, with Cutek timber coating www.timbercoatings.com.au .
My current board is a few years old, I gave away my last plastic board a couple of years ago.
go well,
Colin
Colin
