Just how much faster?

Having only paddled one surfski (my Steller SR) I'm curious just how much faster a " fast" ski is on the flats. After 3+ months I can maintain about 10.2kph over 10K. I have a long way to before I can justify getting a faster ski but I was courious. If I sat myself down in a Steller SES or V12 or... ( fill in fast ski name here) ...and put out the same effort as it takes for my 6.3 kph in my SR, how much faster would it be? I reliize there a number of veriables but assuming flat water and I'm stable enough to put power down... How much faster would it be?

Bill..

You will be paddling at 11.5 km over 10 km. U did mention flat water?

I can answer your question precisely. I have an fenn xt and a couple of weeks ago I tested the swordfish, vajda hawx and the v10. My best speed ever on my xt was 10.4kph for 10kms. That is after 1000 Kms of paddling.

My first 10 km on the v10 I averaged 10.4kph. My times on the others were similar.

I chose the v10 as the best boat for me.

I think when I am used to the boat and the conditions are most favourable I will hit 11kph.

So in response to your question I think a faster boat gives you about .5kph. After that more speed comes from fitness and technique.

At lower speeds, resistance is influenced more by surface area than by wave or form drag. The opposite is true at higher speeds. Both lines intersect somewhere around 10-14 kph or so, from the way I understand it.

The SR looks like it's shorter ski so it may have lower surface area than the V10 and other elite skis. Therefore, at the 10 kph speeds that you are paddling, the SR and other shorter skis might have similar or lower resistance compared to the elite skis. Once you get fitter/better technique/etc and going faster, the shorter and wider SR will produce comparatively greater wave drag and greater overall resistance than the elite skis. So, at some point, as you get faster, you'll get the speed advantage from an elite ski - providing of course that you're not bracing at all.

Way back when, I thought the Fenn XT was about 0.5 kph slower than the millenium at speeds/power input of about 13 kph.

The logic is right, but from charts I've seen, the lines intersect at lower speeds, around 4.5 miles per hour, which is under 8km per hour. Meaning, wave making resistance makes-up the bigger chunk compared to friction at speeds above that.

However, friction is not constant - it increases with speed too. The difference in frictional resistance between a longer and a shorter ski, IMO is minimal. So, for practical purposes, at any reasonable ski speed, the main difference is in effort necessary to reach maintain that speed. And that is due mainly due to differences in wave making resistance, friction being pretty much equal of practical purposes, IMO.

So, if you are paddling slow-ish, at say 5mph or less, it should not matter much which ski you paddle. Above that, "faster" skis will require less effort to maintain the same speed than slower skis. That ignores the stability factor, assuming on flat water one can master the faster but tipper skis reasonably well.

Now, there is a more noticeable difference in friction between an 12 foot 22" wide kayak and a 21 foot long 18" wide ski. The kayak will be easier to paddle at speeds below 4mph or so. It has as much as 20-30% less surface area than the ski (forgot what this means in terms of frictional resistance, but it is lower for the much shorter boat). But between a 19 foot long 19" wide ski and a 21foot long 18" wide ski, the difference in frictional resistance should be negligible...

One thing you are forgetting, the shape and balance of the hull. When you accelerate and if the nose lifts up there is a problem, drag will increase as you go faster. Chose your ski wisely!

But the most important thing is to be stable, one brace stroke and your done with speed, fall out and you are stationary, get the slowest ski and you will be faster, in fact swim and you will be faster!

My guess was something like .5kph. My interest was mostly academic as I'm not in the market for a new ski (he says). And I'm well aware that stability rules.

I'm guessing that the extra roundness of an elite ski offsets its extra length/ surface area over a shorter, wider more stable ski. The extra glide over a beginner-intermediate ski would be welcome.

Bill

Hi Bill.

A few of the guys I paddle with have SR's and have moved to the lightweight construction for quicker and more responsive skis!

My SR is an Advantage layup and wouldn't mind if it was a bit lighter but 32lbs/ 14.5 kilos isn't exactly a tank. But i think i will get more bang for the buck if i spent my future "lite boat" money on something faster. Nothing wrong my SR, i suspect it will be my only boat for some time and my rough water boat for some time after that.

Bill

I have paddled a Fenn XT for about 6 months while waiting for a Fenn Glide. IMpersonalO, the Glide is about 1 kph faster or more.

A relaxed speed in the XT was about 10.6-10,8 kph, and a similar effort in the shows speed about 11.6-12.0. No science here, just recognizing the typical numbers on the GPS.

When doing short sprints (0.5-1.0 min) I find the XT hard to paddle at speeds above 14 kph, while the Glide is hard to get over 16 kph over the same distance.

To me it seems like the XT starts to sit on its stern at speeds above 12 kph. During sprints you can notice how the bow wake moves back toward your feet as the speed increases. In the Glide this is almost not noticeable, at least at my speeds.

BTW, I paddled the XT with about 4 cm of padding in preparation for the Glide. The Glide is slightly less stable than this set up.

Hi Bill
I paddle an SES and my wife an SR. When we first got the SR I time trialled it, just once, but over my standard flat water course which I consistently paddle in 1 hour 20 minutes in my SES averaging about 11.5km/hr. In the SR it took me 1 hour fifty (10.4km/h) which is 110% of my time in the SES.
In the sea I am not comfortable in the SES so usually paddle the SR. When it's lumpy I can keep up with my usual buddies (similar speed when I am in my SES) grinding upwind in the SR. Downwind when I am in the SR they pull away quite quickly in their faster boats - I guess they have just that little bit more top speed to catch the runs better. I don't mind though - I am still having fun in the SR which is way better than being terrified in the SES.
Cheers
Brad

Thanks for that Brad... Almost one whole kph faster, that is significant. Makes me think of all the people I could keep up with on group paddles. Now if I can just find a ski that is as stable as the SR and as fast as the SES!




Bill

The SEL would be close to the speed of the SES but is more stable. Would be worth trying the new SEI which I have not paddled, kind of depends on what you weigh as well.

I'm about 198 lbs/ 90 kilos or 14 stone depending on what part of the sphere you live. I'm planing on paddling off about 25lbs/ 11 kilos or 1.7 stone in the next year so I think the SEL or the SEI might be the ticket. I'm in a situation where I can only have one boat for space reasons and a 21+ foot long boat might be too long. I'm eager to hear about the SEI's speed and stability...... I suppose I'm not the only one.

Well your the right size for the SEL, like I said that would be so close in speed to the SES and for your size probably no different. It is however a lot more stable.

I moved to a Swordfish which is more stable again once I went down from 83kg to 72kg as the SEL got a bit corky for me in the rough but I doubt you would have this problem at your projected and existing weight. I expect the Swordfish and the SEI would be similar in stability, the SEI more stable probably as they are similar in dimensions. The SEL is faster than the Swordfish in my opinion, as you would expect. The Swordfish is fun in the smaller runners, catches them easier than the SEL for my size. But as you already have an SR I don't think the SEI/Swordfish is going to fill the niche like the SEL would.

Opps edit, sorry I got you mixed up with someone else on another thread and thought you already had an SES as well, be worth your while to try both the SEL and SEI before making your decision and weighing up which suits your needs better, or perhaps even the Swordfish, very popular here and is a great ski, I know many guys your size that love it as well.

Greg,

Your switch to the Sf is good info for me. I have an SEL, which is a great boat and my first ski. I have some fast kayaks that I have paddled and raced for years and my speed in the SEL is only a few tenths faster. I can average in the 6.8-6.9 MPH range (over a 5 mile course) in my kayak and only a couple of tenths higher in the SEL. That says more about me than the boats. I am totally comfortable in my kayaks and don't think about stability. In the SEL, I am pretty comfortable but probably a bit more tentative than I realize. I weigh 148lbs and have been thinking of a more stable ski as most of my paddling is solo in cold water. I am considering a Swordfish, the new V10 or the new SEI. I am looking forward to some comparisons when more paddlers get to paddle them. It sure is great to have so many options.

Ken

Sorry, made a mistake in my earlier post, of course I meant when my weight dropped 11kg to 72kg the SEL got corky for me in rougher water, this is the 11kg Excel option, at 67kg you would notice it too Kennneee. In the flat it is fine and small chop its more stable than the SES so I'm going to continue to use it in place of the SES for the rest of winter as it is more stable for me overall. Just in the bigger and windier stuff the SES sits down in the water better for me and the secondary stability engages.
I also was quite surprised that my speed wasn't much faster than some of my kayaks when I first started paddling skis, thankfully this is now on the improve.

I've just moved from a 10.5 kg fenn xt to an 11.9 kg v10 ultra.

I've only had a couple of paddles but I reckon I am .5 to 1km hr faster over 10 Kms on the v10

The big different between the boats aside from the fact that the v10 is sooo long is that there doesn't seem to be any limit on the v10s speed. At my level of ability I am really pushing the xt at about 11kmhr. I'm finding with the v10 it just goes faster and faster the more I push. I would imagine that the v10 starts to top out at 14. I don't have the fitness or power to reach this.

The open ended speed of the v10 actually has me paddling harder. I think I was hitting the resistance point of the xt and stabilising at that speed.

So I'm reviving this thread with an update. Upgrade fever got me and i just acquired a new V10 ultra. So to answer my own question... its about .3 mph-.5 kph faster than my Stellar SR at a cursing pace. I have been religious about my long slows lately and at 65-70% max HR I'm now cruising at 6.6 mph-10.6 kph. I suspect I might pull out another .1 mph out of the boat at that heart rate once i settle into my new stroke. The lower seating position and narrower catch and new stability curve will take a little time to get comfortable with. I haven't pushed it yet so maybe i will do a time trial in a week or so once i feel more settled in the boat. I'm hoping i will get a little bit more that .3 mph- .5kph when driving the boat harder, we shall see. So far... very happy.

Bill

I did some tests a few years ago and was very surprised how little difference there was between the top and bottom end boats.

Test conditions were flat water with no wind, speed was monitored with a GPS.

The skis tested were an old glass XT (~18kg), an old glass Millenium (~18kg) and a Olympic style K1.

Maximum speeds were:

K1: 16.9km/hr
Millenium: 16.9km/hr
XT: 16.1km/hr

Water length line does not seem to play a role, the shortest (K1 at 5.2m) and longest (Millenium at 6.5m) had exactly the same top end speed, with the XT less than 5% slower.

Then I measured my heart rate at a constant 12km/hr, which is a solid pace but still possible to have a conversation.

K1: 144
Millenium: 144
XT: 149

There is a noticeable difference between a heart rate of 144 and 149 (max HR was 191) but mathematically once again we are talking of less than 5%.

My conclusion is that for most people the psychological difference is actually more important than the physical difference when it comes to boat speed. If you like the boat you're paddling you'll go fast in it, if you don't like it you'll go slow.

So make very sure you like a ski before buying one.