Boat weight

13 years 5 months ago #2303 by Gavin Gottschalk
Boat weight was created by Gavin Gottschalk
I'm interested to hear from other readers what difference they think the weight of their boat makes to their performance. Clearly the top guys think there is something to it otherwise they wouldn't be paddling expensive 9-11kg lay-ups! But what about Mr Average middle-of-the-pack i.e. me! Would an 11kg carbon Robberg Express (in theory, as it doesn't exist) give me a big advantage over my current 17kg version? Logic tells me it would, as for a fixed 'horsepower' (me) it seems to stand to reason that I'd get more power/acceleration/speed with a lighter load. Perhaps it is different for varying conditions e.g. flat water vs downwind etc. Definitely nicer to take on and off the car, but is that worth the huge extra cost....?!

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13 years 5 months ago #2304 by Franklin
Replied by Franklin on topic Re:Boat weight
Greetings from sunny Florida, USA
I'm not sure my 25.5 pound (11.6 kg) Think Evo makes me go any faster than my Value 37 pound (16.81 kg) Epic V10 Sport. I didn't think weight would matter at all until I got the lighter boat (Epic makes very light boats too). Taking the boat to the water and especially after a paddle when my boat is wet...light boats are awesome.
Go carry one and you'll be spoiled! It won't matter if all you have is a heavy boat. You'll get used to carrying it. BUT if you get a heavy boat, don't pick up a buddies light weight boat.
Good luck
Franklin

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13 years 5 months ago #2305 by cjborg
Replied by cjborg on topic Re:Boat weight
Somewhere on this forum is an explanation about weight distribution vis-a-vis the paddler versus the boat; i.e., extra weight on the boat will be distributed evenly, creating relatively more mass in the bow and stern, which affects handling, whereas weight on the paddler is centered, affecting handling less and (one hopes) providing some additional power, as at lease some of the weight will be muscle. Thus, shedding a little mass from the proverbial spare tire mioght not have exactly the same affect as spending extra money on a lighter boat.

I have both a carbon XT and a glass XT: I can feel the difference in the water, but not sure I am really faster in one than the other... I'd have to do a very well controlled test to find out, but it does stand to reason that all other things equal, a lighter boat will be faster. How much faster is the question.

I sure like carrying the carbon boat better. On the other hand, my glass XT can take a beating... not sure the carbon would.

Personally, I think this issue boils down to ease of carry, durability and cost much more so than performance, at least for the average racer. Below the most elite level, I would bet performance is most affected by mechanics and fitness.

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13 years 5 months ago #2325 by Will Hardman
Replied by Will Hardman on topic Re:Boat weight
Hi,

I now paddle a Think Legend 12kg compared with my previous 18kg spec ski. It is like chalk and cheese. Faster on the flat and Faster on in downwind and Faster in upwind. Why? Because it is lighter and therefore the same amount of force will push the lighter ski faster.

Simple.

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13 years 5 months ago - 13 years 5 months ago #2326 by cjborg
Replied by cjborg on topic Re:Boat weight
Will,

I'm delighted to learn it is so simple to figure this out, but I'm curious to know how you were able to deduce that weight makes the difference rather than boat length, boat width, hull shape, and other differences between a spec ski and the Legend.

Do you think it would be important to hold constant all the other variables other than weight to determine whether weight really makes a difference?

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13 years 5 months ago - 13 years 5 months ago #2327 by superted
Replied by superted on topic Re:Boat weight
IMO found lighter boats (stiffer and more boyant as well) accelerate better, thus getting onto runs that you might miss by split second in a heavier boat of the same or similar design. Definately the wallowing factor dimishes with a light boat fro me anyway. For instance I find a V10 Ultra quicker then V10 17kg. The same for my V10 Sport ultra compared to a V10 Sport Performance and my previous EVO 12kg. Incedently i feel the V10 Sport Ultra is faster for me then the V10 (17kg) that i paddle regulary.

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13 years 5 months ago - 13 years 5 months ago #2328 by cjborg
Replied by cjborg on topic Re:Boat weight
Ted,
Couple of questions, as I'm interested in conducting similar tests:
Did you do these comparisons on flatwater, or in waves, and if waves, how did you control for wave conditions? I assume on flatwater you could measure wind speed and assume the current over the same course was rather constant, but wondering how to do this in waves?

How did you control for effort level, as it seems one might tire over the course of several repetitions in one boat, then several in another, etc... or did you do the tests over sufficiently short distances that you think effort was not much of a factor?

How many repetitions did you do in each boat, and how long (distance) was each rep?

Just curious about the boats you mention... you were comparing a 19 inch by 20 foot V10 Sport in Ultra layup with the same boat - V10 Sport - in glass? - and then against the 17 inch V10 in glass and Evo in kevlar (19 inch by 20.5 feet) ... or did I misunderstand?

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13 years 5 months ago - 13 years 5 months ago #2329 by superted
Replied by superted on topic Re:Boat weight
Cjborg I did'nt get that anal about "testing". These were my feelings of paddling the same areas (flatwater and ocean) day in day out sometimes with GPS sometimes not, like wise 2 boats in the one day or alternate days or weeks. If i consistently give what i think is a max effort and the boat performs a certain way (catching runs, setting a certain time over a flat course and the effect of rebound waves) then thats good enough for me. At the end of the day nearly all the test and reviews of surfskis are only opinions.

Good luck setting up a controlled environment of waves and currents to get more accurate tests done. :huh:

I currently paddle a V10S Ultra and a V10 17kg. Previously i had an Evo and was borrowing the above V10, V10 Ultra and infrequently a V10S Performance.

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13 years 5 months ago #2330 by Gavin Gottschalk
Replied by Gavin Gottschalk on topic Re:Boat weight
Thanks for the comments- keep them coming.
My impression when I paddled a slightly lighter boat a couple of times was that indeed I did have a bit more fizz in my performance. But is was only a couple of paddles and the conditions weren't 'controlled' in any way.
But think of the opposite situation: when one gets swamped and the footwell and bucket fill with 10 kg's of water, then we all know how sluggish it is to get moving again while the water drains, compared to a dry boat. That's the differnce between 17 and maybe 27kg. Perhaps then the difference between 11 and 17 kg is similarly significant?
Another thought: if anyone ever does really rigorous 'controlled' tests, then they can't be allowed to carry the boat to the water and hence know which one they're about to paddle. In this way the test can be 'blinded' and exclude the 'placebo effect' of knowing you're in a lighter or heavier boat before you start

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13 years 5 months ago #2331 by Franklin
Replied by Franklin on topic Re:Boat weight
Hi Gavin
Great thread you started! I believe the very elite (Mr. Borg, Mr. Chalupsky, Mr. Moche and the other elites not mentioned) paddle the lightest, latest and fastest boats made. There performance level is so high and the desire to win so great that maybe it does make a difference what they paddle. Us'en, Bubba the Yardmen paddlers, should "love what we brung" and make sure it is a boat we are very comfortable in (not sure one boat fits all?). I know I want to win, just started racing, but I sure look at the backs of fast paddlers. The fastest paddler's (aerobic/anaerobic, forgot which one it is?) threshold is at or close to their maximum heart rate, so I've heard, (they can paddle wide open for a VERY long time). I can't. I think they could beat the rest of us on a sheet of plywood. I've seen Oscar and his partner Greg paddle on flat water. It was AWESOME!
I bought a light boat because I'm older, fatter and lazier...and I could! Status thing you know?
I'm still not sure, could be wrong, that the $4300 Legend is that much better than the $3200 Legend? Maybe it is?
I go out to eat at fancy restaurants and come away thinking the plate was big but I'm still hungry. I couldn't tell the food was any better (somethings may be in our mind).
That we're paddling and having fun is enough for me...but I hope I beat you there!
Good luck on getting just the right boat!
Franklin

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13 years 5 months ago #2332 by PeteCress
Replied by PeteCress on topic Re:Boat weight
Coming from windsurfing, I've got to wonder if the apparent speed diff between carbon and glass skis is at least partially due to added stiffness, rather than reduced weight.

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13 years 5 months ago #2333 by nell
Replied by nell on topic Re:Boat weight
Rowing research estimates the change in velocity of a rowing shell at 1/6 of the change in total mass. For instance, if a 100 kg paddler switches from a 20 kg ski to a 10 kg ski, then the speed increase would be 110/120=91.6%, difference is 8.4%, so 1/6 of 8.4 would be 1.4% increase in speed. Assuming 7.50 mph on flatwater with the 20 kg ski, the same paddler would do 7.60 mph with the 10 kg ski for the same energy output.

For 80 kg paddler, and going from 15 kg ski to 10 kg ski, 90/95=5.3%. 5.3/6=.88% improvement, so the above gives us a speed change of 7.50 mph to 7.57 mph.

If this is correct, then while racing 7.5 miles at 7.5 mph would take 60 min, racing 7.5 miles at 7.57 mph would take 59 min 45 sec. So, going from a 15 kg ski to a 10 kg ski would save 15 sec per hour for an 80 kg paddler - or thereabouts, according to this estimate.

Throw in waves, accelerations, then the difference in speed might be greater if the paddler is a less skilled wave rider (and has to keep accelerating to catch waves). But, the steadier the speed and the better skilled the paddler in letting the waves accelerate him or her, then the weight difference might not be as much?

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13 years 1 day ago #2829 by AndrewN
Replied by AndrewN on topic Re:Boat weight
I've never had the good fortune to own a super light ski but coming from a Flatwater K1 perspective, my 8kg Nelo marathon boat compared to a 12/13 kg boat of the same shape is hugely faster accelerating and easier to maintain a speed at.

I think that for anyone in the top half of the field it will improve your results and cut down on fatigue on longer races.

Just a bit scary owning a couple month's salary in Durban with the size of waves we get here...

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