For those interested OC 1 Design/Technical Articles

I added a section to my blog under 'OC1 Design - Reading', where I plan to post technical articles that relate to 'what makes a boat fast ?'

It is somewhat difficult to put full documents into a blog, I am experimenting how that can be done best. If anybody knows how, let me know.

If you have interesting articles that you would like to see in that section, please let me know.
Most recent:

ON THE SUBJECT OF HIGH-SPEED MONOHULLS - Savitsky

http://oc1design.blogspot.com

Submitted by eckhart diestel on Sun, 11/30/2008 - 8:41pm



ambitious project, Eckhart


#1 Sun, 11/30/2008 - 9:27pm


Capnron - physics is nothing more than the detailed analysis of what we see and do.

If you hold a spoon under a faucet with its convex 'rocker' surface into the stream, what happens and why ?

Not really ambitious, rather interesting and to a degree clarifying.

Computer design is entering the OC market; that is understandable if you need a faster boat max every two years to stay in business.

A new OC1 with a computer designed/optimized hull will be available some time soon in Hawaii. According to some of the predicted numbers, it will be very good.

Let's hope that the prices will come down a bit, too; but that will take a few more years ?


#2 Sun, 11/30/2008 - 10:08pm


"A new OC1 with a computer designed/optimized hull will be available some time soon in Hawaii."
Sounds interesting, can you elaborate who's working on that?


#3 Mon, 12/01/2008 - 7:36am


it's called a hurricane.


#4 Mon, 12/01/2008 - 8:13am


Rambo mentioned that a new Hurricane is in the works, didn't he ?
I don't know the builder. This comes from a general discussion about hull design for Hawaiian conditions.


#5 Mon, 12/01/2008 - 9:01am


About the time that the hurricane was being CAD produced the carbon fibre reps where telling us composite fabricator/boatbuilders that carbon fibre would come down in price as usage of it increased. This began to happen, then Airbus cornered the market and now we are expected to compete with them
The real beauty of a basic outrigger canoe is that it is the paddler that makes it go faster and not the money that goes into the design or materials cost. Sure! when you work towards elliminating the paddling skills with design and materials technology then its possible to create faster human powered paddling machines than a canoe....if increments of speed is the object


#6 Mon, 12/01/2008 - 12:23pm


NOT argueing Goodwakas point in any way but, said to carbon reps. When were we not using it ? For sure there has been shortages as military and aviation have all but pre-purchased entire manufacturing year runs from the carbon suppliers ( only basing this on what reps have told me too : ) and it really has taken its toll on the hundreds of full time albeit small-er time professionals

Supply is getting better as compared to the last rwo years but the price isn't going anywhere down like say gas is. I probably use 1/100th of what say Werner uses and I wonder how those guys got theirs during the past couple years.

I wonder what would happen if all of us boycott carbon for a year or two and just use S-Glass.

stepping off the soap box now
aloha,
pog


#7 Mon, 12/01/2008 - 12:36pm


Military, aviation/aerospace is never going to stop purchasing carbon fibre........they need it. If outrigger canoe manufacturers stop using it the effect on pricing will be worth a gnats fart, and anyway we don't need the stuff, they can have it all. We are only getting it because we are paying a stupid price for it.
Paying so much for a small amount of weight reduction when a single blade stroke suits a craft that can benefit from weight and momentum, is not brilliant.


#8 Mon, 12/01/2008 - 4:53pm


Sorry, meant ALL 'little guy' manufacturers from bows, boards, bikes, boats, etc etc ...

Everyone saying .. o.k., you go first, no YOU go first .. LOL.

The carbon really IS better for (kayak/ski) paddle shafts for one.

aloha,
pog


#9 Mon, 12/01/2008 - 5:45pm


If you build with S-glas, epoxy, foam core and vac-bagged...
Would it be that much heavier than carbon ? what about stiffness ?


#10 Mon, 12/01/2008 - 6:13pm


The weight of the fabric is the same with glass or with carbon. 6oz. per yard is the same with either material. There is a noticeable difference in stiffness between the two materials but there is no evidence to predict that this would substantially increase the speed of a canoe going 6-8 knots in the flat and 10-11 knots on a wave. Maybe Eckhart can do a study to determine how much faster a carbon fiber hull is compared to a glass/foam core hybrid.


#11 Mon, 12/01/2008 - 8:43pm


Uh-oh, the stiffness question is back.....

we all agree that if we have a choice between a stiff boat, and a stiffer boat, we'd take the stiffer boat. But usually a stiffer boat costs much more and is it really faster and worth the additional cost?

Man you guys don't know how much self-restraint I'm using right now..You guys are proud of me right?

Poopie stiffy


#12 Mon, 12/01/2008 - 9:00pm


Tommy, you know that that has been studied in yacht design. Every motion, including vibrations etc. requires/consumes energy. The stiffer boat should theoretically have less of such loss.

For OC1 you are the better person to do a study.

You are using 6 ounce/yard ? I used 3 layers of 4 ounce S glas plus core mat - is that overbuilt ? Maybe aluminum/carbon would be better.

http://books.google.com/books?hl=en&lr=&id=wzIaUQ9pDOMC&oi=fnd&pg=PA301&...


#13 Mon, 12/01/2008 - 11:17pm


Eureka! The aluminum oc1! Couldn't be beat for durability. Here in Washington, those old Grumman aluminum indian style canoes are still used, although I don't think they've been made for decades. Not the lightest things around, but they sure can take a beating.


#14 Tue, 12/02/2008 - 5:21am


eckhart diestel,
you use 1mm coremat or 2mm?
i would love to see on your blog different layup combos for regular fibrglass or/and hi-tech state of the art composites....

would be an enormous help for those of us that are starting on this fine art of canoe building.......

right now i build regular fiberglass-polyester boats in the 40 pound range........(dont get scare its the only we can afford) and i use single 4oz-2mmcoremat and a single 6oz .

mahalos for the kokua.........


#15 Tue, 12/02/2008 - 6:00am


I think an important innovation in OC-1s would be to make them adjustable for paddler height at the pedals, like a surfski, instead of at the seat. I would think that OC-1 designers must consider where the boat is loaded--that is, where should the weight of the paddler be, relative to the rocker. If the seat is stationary, the paddler's weight would always be in a particular place.

Of course the drawback would be the difficulty in doing relay races with team members of disparate height. However, we probably have that problem presently anyway.


#16 Tue, 12/02/2008 - 8:33am


Hi Mariano; I used 4 ounce S inside -1 mil - 4 ounce S - 4 ounce S glass outside. The weight is ~ 22 lbs right now without ama using epoxy. The final paint coat will add some more weight. Does polyester layup weigh so much more ?
I thought about building 'double core' with 1 mil but as I did not know the final weight, I did not do it. It feels stiff enough - so far.
The next boat should come out a little lighter, as I made my share of mistakes that I needed to correct.

It would be nice if the builders would share their layup experience. According to google there are also several journal about composite materials.


#17 Tue, 12/02/2008 - 8:40am


Stiffness?.......Narrow beam of an outrigger canoe allows enough hull curvature to create sufficient stiffness without resort to CF. Even hulls with PVC cored e glass laminates have enough stiffness to retain their shape under most conditins of normal use, so how can energy losses cause a performance drop off.
The extreme surf conditions where water pressure can cause hull deflection enough to effect performance are theoretical rather than actual. Dropping into a really hollow wave where a canoe does not pearl will show no benefit of some small energy use by nature of hull stiffness......... there is a huge excess of energy available in the situation anyway.
Assuming that stiffness does not come at the expense of weight, the flexural modulus of the laminate is no big deal.
Sure, the superior stiffness of CF allows weight reduction by permitting thinner laminate skins, compared to thicker glass skins...........strangely enough big wave tow in surfers are adding lead weights to their boards to utilize available energy


#18 Tue, 12/02/2008 - 10:03am


hard to compare tow in boards to this scenario. they are pulled into a wave by a machine, so the rider does not have to overcome the heavy board's desire to stay put or to sit deeper in the water.

there are some rare occasions where world tour surfers are using very small weights in their boards. many seem think this is done to balance center of mass on a board. especially since fins and fin systems often cause a board to become tail heavy in the case of an ultra light pro tour surfboard.

also, i'm not sure if this is true, but i have heard the reason tow boards are heavy is to keep them in contact with the water. as tow surfers go faster and faster, the boards are lifting off the water and catching air under their hulls. loosing contact with the wave causes a loss in control.


#19 Tue, 12/02/2008 - 10:51am


Waves big enough to require towing in are often mixed in with pretty choppy conditions. Encountering this chop at the speeds they go, it's beneficial to have some weight under your feet to keep board from being deflected by the chop (even when it's relatively flat); it's about inertia. Boards big enough to paddle into larger waves already have what weight. I believe it analagous to skiing through the crud at speed and the choice of skis for those conditions. I caveat this with that although I've paddled big boards into big waves I've haven't [yet] towed into a real monster, but if I did I'd want some weight down there.


#20 Tue, 12/02/2008 - 12:35pm


in past 2 years we had a carbon shortage ,but now its no problem as both Boeing and Airbus have delays on their composite intensive planes so a lot of carbon was released on to the market .I in aditon to a workshop also run a small time as sales rep for SP(now Gurit) so the price is still good an suply plentifull ,but 2 years back it almost dryed out but another dealer friend of mine who supplys a lot to Ferrari somehow allways had stuff on stock so i use to buy of himm.(i suspect is was a proper 'italian job' ,you know it ''fell of a truck'' ,but i dont care as long as i could get it .And one good thing is that he now and then has some discounted stuff that was custom woven for Ferrari to some unusual weigh ,patern or size but is left over from their projects. But now days is no problem to get it .
Tipp:If you want cheap top spec carbon put some more effort in it and do the boat with unidirectionals (1/3 of the price of woven stuff)

For stiffens do a thicker foam core as stiffnes is cubed with dubble thickness and weight only increases fractionaly ,you could also use PMI type for for less resin upake ,Core cell is also low on resin uptake.Soric for less hasle and coremat as a last resort as it is realy heavy


#21 Tue, 12/02/2008 - 1:04pm


canoemaker - how do you wet out the unidirectional carbon fiber effectivly ?


#22 Tue, 12/02/2008 - 1:24pm


Weting them uni is teh simplest of them all you just have to go the along the fibre ,but now days i mostly infuse or do in prepreg ,inusion once mastered is a very stright forvard process and requires much less skill do do than a proper wet layup with vacum baging .So i am much more flexible with hiring aditional workers in the spring/summer season.
Prepreg i mostly use for realy top spec stuff and not much for kayaks or canoes.pecause you need to paint the part ,but prepreg Uni is actualy cheaper than the dry one ,reason for that is that the fibre is not stiched and the machine making it makes more meters per minute than for dry which requires stitching.


#23 Tue, 12/02/2008 - 1:42pm


Thank you


#24 Tue, 12/02/2008 - 1:52pm


I think there's two advantages to the stiffness of a carbon hull in a canoe. Speed/performance which no one has really measured/calculated, but more importantly durability. For a given weight or even a lighter weight a carbon lay up will be less prone to pressure dings, dimples, oil canning. So it might cost more, but it pays for itself in a longer useful life of the canoe.

And yes poops, I for one was impressed with your restraint.


#25 Tue, 12/02/2008 - 2:02pm


Okay here were some considerations I made for my V1 design you can check out my canoe here:
http://www.facebook.com/media/set/?set=a.1261532094071.2035055.110275612...
My hull weighs in a 30lbs. The ama is just some scrap foam I used while I dream up something better. (looks like I am going to carve out a 5" diameter Bamboo to stay with the natural these of the canoe hopefully around 2lbs?)
Maybe these variables are already known and I just haven't found them? I've seen research and information with regards to racing kayak hull design by marine engineers, but they admit that these studies have no calculations for above water "wind", or wave sea conditions effect. With my new design I would like to see more races that incorporate an upwind leg. Sorry, haven't entered a race quite yet, had rotator-cuff surgery and I'm still finishing the new ama.
Knowing that racing K1's use the widest point aft of center/seat (only around 15" think I'll go a little wider next time)
Improved Tracking is done with a Deeper V-shaped chine
A hard-chine adds maneuverability (didn't think this was really needed as I'm not doing hard turns by leaning might want to add some to the rear for surfing)
Pearling is usually prevented by an enlarged bow (next one I'll arch the foredeck to reduce volume some and maybe weight)
Considering most races are downwind a downwind version might be helped by a higher seat placement as long as stability doesn't suffer. This might be adjusted in Iako shape and position?
I toyed with a more surfboard shape in my scrap foam ama thinking it would be less drag and effect tracking less, but made the whole ama too small (slight lean made it sink). Maybe I'll try that again. lol, I could barely turn at all!
If we had more upwind legs I think a little bit of weight might actually be a benefit due to sitting a little lower in the water and having less side-to-side from wave action.
See ya in the Surf!


#26 Sat, 03/03/2012 - 6:47pm


Hey Boatholder Bill,
wich is the overall lenght of the canoe?
It looks amazing.


#27 Sat, 03/03/2012 - 7:13pm


21' on the nose. I'm 220lbs so it sits a bit low with me in it!


#28 Sat, 03/03/2012 - 8:08pm


I've lurked here for a while -- first time I've felt I had something to add to the discussion.

Bit of background. I have a Masters degree in Naval Architecture from UC Berkeley and am the owner of the Maas Boat Company in Richmond, CA. We've been building open water rowing shells for 30 years and are starting production of an OC-1 called the Soliton.

We use a two-skin laminate with syntactic foam core between the skins. Three skins is clever but a great deal more work. I second the recommendation against coremat -- it really soaks up resin and gets heavy in a hurry.

Think about stiffness of the hull in two dimensions. There is overall bending stiffness bow to stern and there is hull flex (oil canning). Overall bending stiffness matters for speed, but oil canning doesn't seem to matter within reason (inflatable boats are really slow). There is a flatwater rowing shell built by Fluidesign that is a single skin carbon layup. There are parts of that hull that will oilcan with the slightest pressure. And yet the boat is fast and competitive. I recognize that it's not going through waves, but you have to feel this hull to get a sense of how easily it oil cans. The Fluidesign hull is quite stiff bow to stern.


#29 Wed, 03/07/2012 - 5:10am


Hey Doug,

I got the chance to check out a Soliton last weekend at Dana Point. It's a great looking OC1 but seems incredibly narrow through the "cockpit" area. Was there a reason for this design and how narrow you kept it?


#30 Wed, 03/07/2012 - 5:18am


skinnier boat = faster boat mentality, less wetted surface area?

I don't see why oc1's haven't gotten skinnier considering you have an ama for balance..

Surfskis can only get so narrow, the more narrow the tippier it gets for the most part. Not an issue on an oc1....


#31 Wed, 03/07/2012 - 7:33am


Narrow has less base and deeper you will sink also. To sit on. Less base and each pull, the canoe moves up and down more. I guess it could be compensated for by the technic like sprinters. the future.


#32 Wed, 03/07/2012 - 8:45am


Sorry for the delayed reply -- I got slammed with work for a bit.

Thanks for checking out the canoe (the Soliton) at Dana Point. The idea is precisely as you see it -- to make a skinny hull. isotopez's thoughts are a good statement of mine. The maximum beam on the Soliton is 12". This is an inch or two narrower than most other canoes. On an OC-1 we still have a bit of a problem with beam because you have to get a seat in there somehow. With the Soliton I get enough width for the butt by making a separate carbon fiber seat pan that slides in a track. This gives the side support without requiring that the hull be 14" wide.

What skinny does for you is reduces the wave-making and, with the rounded section shape I'm using, reduces the wetted surface. What has surprised me is that the Soliton doesn't seem to be noticeably faster than a lot of boats in the flats, but the skinny nose allows it to catch waves really, really well. I find that in races like Dana Point with an upwind leg followed by a downwind leg, I make up a fair amount of time on the downwind legs. Dana Point didn't have much to catch, but it was the waves that allowed me to pull back four or five boats downwind.

Doug


#33 Thu, 03/08/2012 - 3:18pm


having just purchased an older oc(Seahorse) in aus. i notice that the seating position is about 300mm towards he rear. having owned some later oc's I was surprised how far back the seating postion was. I was playing around in the surf and placed my but 300mm forward and surprised how much better it picked up the runs . my feet where well and truly out of the footwells. how far we come.

THXS

Boss


#34 Mon, 03/12/2012 - 11:20pm


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