Wow a serious post from me.
I have a question and this only pertains to 6-man canoes because the benefit of foam core is obvious in OC-1s.
Is there a benefit in using foam core vs. standard lay-up in six man canoes? Someone told me that it makes all the difference. I thought about it and I can't imagine how much difference foam core would make. Here are my thoughts.
- Foam core eliminates weight while adding to the strength. But all 6-mans have to be 400 lbs or more here in Hawaii. 400 pound standard lay up boats are plenty strong. So no help there.
- Foam core makes the canoe stiffer but does that stiffness really make a difference? I understand the concept of flexing dissipating energy but a standard lay-up boat can't flex that much to make a difference right?
I am a full advocate of the paddler making the difference and not the boat because a good paddler will be fast no matter what boat he/she is in. Being an analytical type person this got my curiosity. I can understand using foam core in other marine vessels but with a minimum boat weight I can't imagine it making that much of a difference. Am I wrong??
poops
Submitted by poopoopaddler on Mon, 07/16/2007 - 3:54pm
stiffness definitely seems to make a difference (talk to anyone paddling the lighter, stiffer surfskis at the moment).
another possible benefit of foam core could be in design and safety. Foam allows more creativity for positive buoyancy in the canoe design, while maintaining stiffness/strength etc. You are then given the option of making an extremely light boat (perhaps with "radical" design), and adding additional weight in strategic places to meet any min weight criteria.
Making a heavy boat has always seemed (to me) to be a strange way of of ensuring a strong boat, especially with the technology that is available nowadays...
my 2 cents anyway,,,
#1 Mon, 07/16/2007 - 10:47pm
Poo,
Think of it the same way in a one man and you have the same for the six man there is a huge difference. If you get the chance to try out both boats with the same crew in the same conditions then you will understand.
#2 Mon, 07/16/2007 - 11:41pm
Tpoppler, can you give more specifics? Why was the foam-core 6-man better? I don't think you can use oc-1s as a comparison to this issue.
#3 Mon, 07/16/2007 - 11:52pm
I can't think of any substantive advantage foam-core OC6 would have over the standard lay up given the weight and hull design restrictions. The standard lay-up is already stiff to begin with. It would seem to me that a "stiffer" foam-core OC6 would only provide a marginal gain over a standard lay up so as to be undetectible in speed and in time. If anything, I would think that foam-core canoes could be a problem when it comes to durability and the ease of repair. I know very little about repairing things with a foam core but would venture to say that if the skin of the hull is compromised, you could experience delamination, deterioration, etc. of the core--- like with surfboards. I don't think this would be a problem with the standard lay-ups; and repairs are easy to make. Now if the design and weight restrictions were lifted, I think there is a huge potential for foam core-designed canoes.
#4 Tue, 07/17/2007 - 9:46am
Snarfblat, my thoughts exactly.
Poops
#5 Tue, 07/17/2007 - 9:59am
.
#6 Fri, 03/02/2012 - 8:35am
The lighter construction would in theory allow you to position additional required weight optimally.
And, of course, stiffer in this case is better (more effective transfer of energy).
SE PDX, US
#7 Tue, 07/17/2007 - 8:22pm
I can't comment on the stiffness issue, but in regards to Snarfblat's comment about the ease of repair it depends on the construction technique. With epoxy and coring materials that are closed cell (ie they don't absorb water) delamination is much less of an issue and repairs are much easier than with surfboards.
I agree though, the extra money is probably only worth it if it's going to be a lighter boat. What's the difference in cost anyway?
#8 Tue, 07/17/2007 - 8:52pm
On a Lightning I believe the difference in price is only $500.
#9 Wed, 07/18/2007 - 11:32am
Does anyone know what is the claimed benefit of foam core in the Bradley lighting? I'm curious about that.
#10 Wed, 07/18/2007 - 1:15pm
I think you are underestimating the importance of stiffness, any energy lost into the water rather than across the water is wasted. for the middle of the pack crews the advantage is obviously less, However lets take the top crews, 1-10th place we see on many occasions that races are lost by less than a boat length. If you are loosing lets isay 6 inches every minute to the boats flex in the water, Seems like a minmal amount and an acceptable loss. now multiply that by 60 minutes, now we are talking 30 feet, nearly a boat length, over two hours 60 feet, and across the channel 5+ hours 180 feet or 60 yards, now we are talking real losses, in 60 yards you could have lost two to five places. Our sport has grown to sometyhing far beyond a casual paddle down the river, There is real money involved and sponsors and with the amount of training the top crews commit to why would you want your equipment holding you back, If you get beat on the course because you make bad decisions or there are better crews fine. If I am in a top 10 crew in any of the big races I want the best boat possible, 500 b ucks is peanuts if it means the crew wins.
OK if that doesn't make a good argument here are afew other examples, A couple years back Bubba Parker had one of my team boats, we all have read the stings about the Canadian built Stingrays. However Bubba's was like no other, relatively light about 24lbs hull and super stiff. Many of the Imua and NAC guys did there time trials on the canoe and had great results that were much faster than there current canoes. Several went out and got Stingray's, They never had the same results, although the boats were a bit heavier, I am sure it had more to do with the stiffness of the hull.
OK last example and I wil shut up. Jump on a mountain bike with no suspention, then get on one with suspension, you loose tons of energy into the road.
I lied here is one more example that may strike a cord, for those that surf, carve a turn on a stiff board, Then carve the same turn on a foam board or soft top, You can't preserve the speed through the turn with a foam board as the energy is lost into the water.
#11 Wed, 07/18/2007 - 4:05pm
Hmm, interesting point oceanohana. I agree that there is some energy lost to flex but I don't think its as much as you claim. It would be very interesting to test this theory and figure this out.
One mans cannot be compared to this situation. One mans do not have weight restrictions. Foam core in one mans has its obvious benefits.
The mountain bike analogy is invalid. A boat's flex is not directly absorbing a paddlers stroke whereas a suspension on a bike is. Plus is a whole different medium. Apples to onions.
poops
#12 Wed, 07/18/2007 - 11:10pm
Oceana,
You bring up some good points about stiffness. However, the problem is we can only analogize the benefits of stiffness based on its effect on something other than a 6 man--and those analogies are imperfect. We really have no clue on the effects of stiffness when it comes to an OC6 until we see some numbers. Your six inch analogy sounds great when you do the math but the problem is, we don't know whether its 3 feet, 6", 3", zero or even -3".
While I agree that any energy lost into the water instead of across the water is wasted, I'm not sold on the idea that 6 fat monkeys bouncing up and down in a stiff canoe will be faster than the same chimps bouncing in a not-so-stiff one. In either case, work is not being expended to move the canoe forward. Since none of that work goes into moving the canoe forward, it cannot be said that work will be lost in a not-so-stiff canoe.
With respect to the Stingray analogy, I would venture to say that the weight of the boat and not its stiffness played more of a significant role in time and speed. Assuming the work of a paddler is constant whether he/she is paddling a stiff Sting or a spongy one and we increase the mass of the canoe just to piss the paddler off. Since Work = Force X Displacement and Force = Mass X Acceleration, an increase in mass would require a decreas in acceleration to keep Force (so that the amount of Work remains the same) the same in any given canoe. Since acceleration decreases, the heavier the canoe is the slower your canoe will be over a given distance. I know mass is different than weight and I may not have applied the formulas right, but you gotta admit, it sounds pretty good. Anyways, point is we need more mechanical engineer paddlers in this damn forum to figure out which canoes is actually better.
The bike analogy sounds good too but I believe is inapplicable. The loss of energy in bicycle suspensions comes from the periodic pedaling action and the suspensions deflection of lateral motion or energy. Since the pedaling action is periodic, the suspension bobs as the rider pedals. The bobbing is thought to be a disadvantage because energy is lost in overcoming the suspension system and also because the pedaling motion and rhythm is affected. The mechanics of paddling is different from peddling. The energy that a paddler exerts to move the canoe forward or laterally is not necessarily absorbed by the flexibility in the hull.
You have me on the surf board analogy.
#13 Thu, 07/19/2007 - 12:48am
I am not saying I know al the answers nor an I saying my numbers are corect, They were pulled at random only to state a viewpoint. I actually think it cold be more. Yes a MB is an onion compared to the canoe, however some of the same pricipals stil apply,
Our club recently had a six man reconditioned, the hull was noticabbly flimbsy, during the reconditioning carbon was added to trengthen the side walls and firm them up, by all accounts the boat has a new feel and seems faster.
Now I understand that OC-1 annalogy may not be exact to six man, however because the stroke and conditions are as similar as we can get I think we can get some of the same results from the testing.
TYSON, Help me out on this, Go get Bubba's boat from Sam, Borrow another Stingray and do some trials, be sure to add weight to Bubbas boat so they are the same. Let us know the results.
Hard numbers are key, I have seen for a lot of years opinons are taken for fact, I am just as guilty as the guy that posts on the web that a Hurricane is ONLY for paddlers less than 150 pounds and nothing to back it, My numbers in my last post were just numbers, no evidence, Unfortunatelly I do not paddle with a group that is consistant enough or fast enough to get solid data. Tyson, You do have the paddlers and the equipment to do these tests in the OC-6,
(on a side note, good thread, 14 posts and Poopoo has not gone all sarcastic on us. Maybe because he started it.)
#14 Thu, 07/19/2007 - 3:02am
Is it the foam core or the material laid on top which provides stiffness? I know the surf tech epoxy surf boards are way stiffer than traditional boards. I believe both have some type of foam core. Exactly what type of material constitites the foam core of the Bradley? Is it still regulation weight? I think Ocean Ohana is right with the reaaltion of stiffness to speed, but of course all my evidence is purely anecdotal.
#15 Thu, 07/19/2007 - 3:58am
Regarding comments on foam core.
Actually the foam provides very little in terms of actual strength. It is the distance that the two (or more) layers are away from each other that provides the strength and rigidity.
If you imagine a steel 'I-beam', the two horizontal sections are held apart from each other by a vertical piece, forming the 'I' shape. The separation (vertical) between the two surfaces determines the overall strength.
The rest comes down to physics, as stresses on the two surfaces then work to cancel each other out (i.e a push/pull effect). This is what provides the strength and greater overall rigidity. You can achieve a greater level of strength and rigidity using a lot less material than with a traditional layup. So you end up with a lighter, stronger part. Carbon is commonly used (with epoxy) because of its extremely high tensile strength, and very light weight. This is why aircraft companies are constructing over 40-60% of the newer aircraft using composite materials and same for formula one cars and racing yachts, which often inclue foam (or similar) core. It's also why there is a world wide shortage of carbon, and why the cost of your canoe has increased lately. Some canoe builders haved switched to using cheaper but more easily available Kevlar and S-Glass (which don't have a high tensile strength).
So why use a foam core? When used in conjunction with composite materials like S-Glass, carbon fibre etc, you end up with a much lighter, and much stronger more rigid canoe - all highly desirable qualities in todays competitive environment.
I'm not sure that I have explained it that well, but there is a wealth of information out there on core reinforcement etc.
#16 Thu, 07/19/2007 - 12:48pm
That's pretty much spot on Coconut.
Guys, if you ever get the chance to touch Karels carbon fibre OC6 (there are a few around) grab the Manu and shake the canoe sideways, it will not flex at all. Now do the same to a standard all glass OC6 and it will flex and wobble big time. If this happens on water the canoe will change shape and be slower, fact. The stiffer hull offers less resistance as it retains its shape better.
Oceanohana, not sure if you were referring to me in your post re the Hurricane being for only under 150LB paddlers, but I'm happy to state that the Hurricane was designed with a displacement weight of 95kg (210 LB) in mind.
Cheers Rambo
#17 Thu, 07/19/2007 - 3:07pm
I guess i'm more of a numbers kinda guy. Unless I see some objectively verifiable data on most things, I don't buy into the hype that easily. I've come to learn that just because it sounds good, it doesn't make it so. Its like waxing the bottom of the canoe to make it faster through the water. It makes sense but has all but been rejected by the yacht racing community. I wonder if there's any paddler out their who has experience in mechanics and the likes who can comment on this issue and explain why or how flexibility affects the speed of the canoe.
#18 Thu, 07/19/2007 - 4:39pm
Is the stiffer=faster thing really just hype? It seems to be true for a number of sports. Don't know 'bout that waxing the bottom of the boat thing, though. Maybe next time trial...
#19 Thu, 07/19/2007 - 6:06pm
Jim I don't doubt that a stiffer boat is faster. If I had a choice I'd go for the stiffer one. We just want to know HOW much faster. Marginal? Substantial?
And anyway I duuno about you guys but I like my boats stiff. And longer the better. That way when stroked right you hit that sweet spot. I often like to polish my stiff, long boat then take it out for a good stroke session.
Poops
#20 Fri, 07/20/2007 - 8:17am
Try an air matress and paddle out and then try a surfboard or even a barndoor and stiffness wins.
#21 Fri, 07/20/2007 - 9:44am
The mattress is great in the surf and doubles as a flotation device, but the barn door is faster in the flats.
#22 Fri, 07/20/2007 - 10:05am
Hmm, I wounldn't mind trying a foam core six man. I dunno that I would be able to tell the difference though.
POOPoie
#23 Fri, 07/20/2007 - 10:42am
I weigh 180 lbs. and paddle in mostly double-overhead choppy wind chop from the South, although I will sometimes race in class V river-rapids. What is the best barn-door for me?
#24 Fri, 07/20/2007 - 12:44pm
Are you also new to the "mountainous area of nor-cal" whitewater kayak scene? What in God's name did you do to that poor individual?
#25 Fri, 07/20/2007 - 12:48pm
Dude, an air matress would be way easier to paddle out and surf. Honestly, there's no way in hell you're gonna paddle out a barndoor and surf it. Impossible.
Seriously, some of your guys' analogies are not relevant. OK if you could paddle a barndoor then that analogy would be like asking "what would you rather paddle a canoe made from yarn or fiberglass. A better question would be would you rather paddle a barndoor made from cedar or pine?
#26 Fri, 07/20/2007 - 12:56pm
Did you ever see those photos of Slater surfing a door at off the wall? I believe it was an exterior solid core model with mahogany veneer.
#27 Fri, 07/20/2007 - 1:14pm
Nope, it was hollow, and once it filled with water it surfed like ass. Is mahognany stiffer than cedar?
#28 Fri, 07/20/2007 - 1:49pm
OK, seriously...
I paddle a new carbon '07 made in China Hurricane. The boat I raced/paddled before that, (as recently as this January) was one of the old Malaysian made snap-button assembly Hurricanes (I've got reliable info that says it's pedigree goes back to Mike Judd, but that's neither here nor there... Just saying that it's OLD.) In real-world tests, on the same day, in the same water I'm up to 10 seconds per mile faster in the new vs. the old. That seems significant to me.
I can't say exactly why this is, but the facts are that the hull designs are exactly the same, but the old boat is noticeably flexier than the new one. There may be other pertinent factors, but I'd need someone else to point them out to me, because I'm not that smart.
I know this doesn't say much for foam core vs. standard lay-up, but I'm a "stiffer is (significantly) faster" ambassador.
#29 Fri, 07/20/2007 - 2:26pm
good to see poopoo is back to the sarcasim, Rambo I was not saying the Hurricane is built for paddlers less than 150, what I was saying is that many times people post info on the web that is not correct and misleads paddlers and is taken for truth, I am am Hurricane dealer and am well aware of the hull displacement if the boat, However i have plenty of people try and tll me they are too big for the canoe at 180 pounds because that is what they read or have heard. Another myth is waxing your hull, Waxing in fact slows your canoe, the water molecules are being repelled from the hull causing more friction, In fact wet sanding at about 400 grit is faster, Water molecules are trapped against the hull allowing water moecules to rub against each other. with less resistance. This info is found all over the web in tests done in very controlled environments.
Goto's findings are a good example of how stiffness wll make a difference, The Early Hurricanes uses a different core than is used today, however many of those boats were as light if not lighter than the new boats, The Hulll and Ama ar the same, and they were stiff. Anyone who has felt the new boats willl notice they are rock hard.
Although the original post was directed to OC-6, OC-1 comparisons are stil valid, and I think that due to the extra length and open deck construction of the OC-6 will only magnify the issue, Add surf into the mix and the issue becomes even more magnified. 10 seconds per mile on Goto's oc-1 is in fact a far greater distance than the numbers I had used as examples.
#30 Fri, 07/20/2007 - 3:44pm
Goto, do the boats weigh the same?
Oceanohana, I dunno whether to take that as a compliment or insult?
poops
#31 Fri, 07/20/2007 - 3:51pm
PooPoo,
You answered your own question there mate...
"Foam core eliminates weight while adding to the strength. But all 6-mans have to be 400 lbs or more here in Hawaii. 400 pound standard lay up boats are plenty strong. So no help there..."
When you have an artificially imposed weight on a canoe, you nullify any benefits that a foam core composite canoe would provide. End of story. Get rid of that nonsensical rule and you'd see the benefits fairly quickly I imagine.
As for strength provided by the foam core - well, its not the foam core itself but the distance that the foam provides between the two shear surfaces (see my original post).
#32 Fri, 07/20/2007 - 6:12pm
Sorry, should have mentioned that before...
Using the scientific "holding-the-boat-while-standing-on-a-bathroom-scale-then-subtracting-your own-weight" method, I found there to be about a six pound difference between the unrigged hulls. About 21 lbs. to about 27 lbs.
I wonder if the four Big-Macs I ate in between matters... Probably not.
Also, the 10 second per mile difference was kept track of, and averaged over a distance of about 3 miles - 1.5 into the wind, 1.5 with the wind - on a Garmin Forerunner 201. (See those GPS things ARE good for something!) If I had to guess, the winds were about 7-10 knots, with minimal wind-wave action.
What complicates this discussion is the extra weight - does it slow the boat down by affecting acceleration, or does it speed it up by adding momentum?
Or, is six pounds negligible when figuring that the difference between boats, fully rigged, with me on it, comes out to about 205 lbs. vs. 211 lbs? My personal opinion: negligible.
Also complicating matters - how tired was I on that second run?
Poopoo - word of advice: take everything as an insult, then remember to love your enemy as thine enemy loves your neighbor... or something like that. My neighbor is a big, fat, ugly, mean, old, stinky, stupid, lazy, republican, fart-licker - so NO ONE loves her. And I'm AT LEAST 10 seconds per mile faster than her, even with the stiffness.
#33 Fri, 07/20/2007 - 8:00pm
Yeah Goto, there are some other variables there. Can you FEEL and difference?
It would be interesting to strap on 6 pounds and see if you are still faster.
It would be more interesting goto, if you did the 3 mile run in both a standard and foam core SIX MAN, by yourself and see which is faster.I'd put my money on goto winning.
poops
#34 Fri, 07/20/2007 - 9:38pm
Stiffness is the reason i have ordered a Chinese made Pegasus over a local (Australia) made Pegasus. Both are double carbon, both the same hull shape. The difference between the two, in feel, speed , response is huge. The local manufacturer is a top guy and builds great canoes, but cannot achieve the hardness nor stiffness of the Chinese canoe without the same equipment as the China factory where the Hurricane and Pegasus are both built side by side.
I can't give you figures or data to back up my claim, but if you accept as a given that stiffness is better, try this simple test.
Suspend both canoes on supports 1 ft from both ends of the canoe, measure the distance from the floor to the underside of the hull, both loaded with 50LB weight and without.
You will find the Chinese canoe flexes heaps less.
If you don't accept that stiffness is better, then this will mean nothing to you.
Trialling both in the same conditions on the same day convinced me as did the Malaysian Hurricane vs the Chinese Hurricane.
I believe the Malaysian Hurricane was "Coremat" not "Divinycell" as in the Chinese canoe and the vacuum bagging pressure crushes the Coremat (softer) and reduces the thickness of the double carbon sandwich, hence the reduction in stiffness and hardness, especially the deck of the canoe. Nothing wrong with this layup, many fine canoes are made this way and are still strong because the overall canoe shape is still a Monocoque design.
One advantage of the Coremat canoe is that it will not dent like a Divinycell one. Ever noticed those dents in your Hurricane where you bang it with the paddle? Coremat will flex and pop back out.
Is stiff .... is good.
Cheers Rambo
#35 Mon, 07/30/2007 - 6:46pm
Rambo,
Not to highjack this thread or nothing, but I would be interested in your thoughts on your Pegasus after you get it. I moved from a China Hurricane and to a China Pegasus and I won't be looking back.
#36 Sat, 07/21/2007 - 5:55am
There was a guy at a New Zealand University with a Russian name who published research data on kayaks, mono hull, two hulls, trimarans etc.
His name was something like Lanauskas. I can't find him anymore, so he probably left the University.
What I remember:
Different hull designs differed 1 -2 % regarding speed. With different I mean comparable difference, example: same beam width, but this max beam width at a different spot etc.
Significant weight differences accounted for the greatest difference in boat speed in his publications.
Regarding stiffness: I would think that less stiffness would mean additional torque, which would mean loss of energy.
Now how about the ama:
Would a stiff ama be better assuming no additional loss of energy, or a soft one with shock absorption and less roll of the boat ? I am sure that there is a definite answer to this question, but I am not sure that anybody has ever done such tests.
Another question would be: in the surf you might want some longitudinal flex as it might temporarily increase the rocker ?
#37 Sat, 07/21/2007 - 3:51pm
Kd, as you have already Hi-jacked the thread, I'll give you my reason for the purchase of the China Pegasus.
Firstly, a few things i found that the Pegasus does better for me (note i said for me) than the Hurricane. I've paddled Hurricane for 3 years now and love it, but at 54, I'm losing my short explosive strength to pull onto some critical bumps that i need to get, to stay competitive downwind. After trialling the Pegasus in downwind conditions i have come to the conclusion that it drops in sooner, with less effort than the Hurricane and doesn't need to be ridden as aggressively to achieve the same result. It's also more responsive to rudder input and also seems to glide better in small clean ocean swells. Upwind and flat water the Peggie is on par with the Hurricane. (again my opinion, from my trials)
End result is my race times should improve because I'm moving to a canoe that covers my weaknesses in the type of ocean conditions that i now race in.
Yes, i could also do explosive strength exercises or gain more downwind skills, if i was 15 years younger i would probably take that option.
I think, it's a smart equipment choice that will result in faster times for me and more comfort in the longer races. The Hurricane will remain with me, we're been through a lot together over the last 3 years, actually i keep all my canoes.
Time will tell if i made the right decision, I'm confident i have.
Cheers Rambo
#38 Sat, 07/21/2007 - 4:17pm
Eckhart, it was actually an Australian Uni, The University of Adelaide
South Australia and his name was Leo Lazauskas.
Here is the website you're referring to.
http://www.cyberiad.net/library/kayaks/racing/racing.htm
http://www.cyberiad.net/hull.htm
A lot of his work was never put into practice because they changed the K1 regulations negating his work. But recently a fellow at NASA has finally started construction of some of his hull designs.
His name ...
Al Bowers, NASA DFRC
Deputy Director, Research/Engineering
Cheers Rambo
#39 Sat, 07/21/2007 - 4:31pm
Rambo,
I doubt you will be disappointed. I have observed all of your points to be true during my transition. Easier drop-in, more rudder response, and considerably more seat comfortable over longer durations. All-in-all a wise choice (at least for me). (Note: I neither represent nor have financial interests in Kai Wa'a).
All:
Okay, sorry for the sidebar, please resume your discussion of stiff vs. soft. My wife says a stiff, rigid one is better. I assume she means a boat.
Later,
Koors
#40 Sun, 07/22/2007 - 9:38am
Thanks Rambo, great to have that link available again.
Sorry about giving the honors to New Zealand, - it is
Australia. Really interesting reading and to the point.
I like your website. How is your camera coming ?
Eckhart
#41 Sun, 07/22/2007 - 8:48pm
Rambo,
I am sure that you have researched the Kai Waa - how does it compare to the Hurricane in terms of displacement ?
#42 Sun, 07/22/2007 - 8:50pm
The never ending debate between weight and stiffness. Frankly the "brain damage" you get from the extra few pounds is when you CARRY it on your shoulder. Because the canoe is 21 ft long, every lb of weight is multiplied by the moment of the lever ( length of the weight applied ) is exaggerated on a point on your shoulder. Yes, I hated Physics in school but Einstein said that if you have a long enough lever, you can lift up the entire world !
ON THE WATER on the other hand in swells, the extra weight for the stiffness gained is actually a benefit because most guys generate far more power than you need to move the canoe, the extra lbs help the acceleration down the bump, but most of all the stiffness of the canoe carves it harder (faster ) Try SKIIING with flexible skis as opposed to stiffer ones.
For TRAINING, I try to paddle with my kids on the canoe. My youngest is about 50lbs. I also enjoy having him hang on me while trying to get on bumps, he screams like a lunatic !! The only downside is that if you're past 40 ( like me ) and your shoulder joints are worn from swimming as a kid, it will make your shoulder joints THROB with pain if you do it too much. I get more sore from that than doing weights !!
Each to his own. ALoha
#43 Mon, 07/30/2007 - 2:10pm
Rambo is absolutely RIGHT ! All other things being EQUAL, double, single or whatever composite cloth you use, the foam core will make it stiffer. Thank you for clarifying the differences.
#44 Tue, 07/31/2007 - 7:09pm