Chunky venturi covers

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6 years 11 months ago #30284 by Canadasurfskiguy
I've been thinking lately and I'm not sure if my thoughts are of the silly hair splitting nature or are of some worth.

I've got an elite sl. It has two venturis, each cover has a chunky lip where it's glued on to the boat and is also quite big. Their much bigger than the venturi cover on my old v10L and I think their bigger than Think boats' venturi's too. I figure this must create a decent amount more resistance than boats with 1 slim cover and definitely more than all the new bailer boats.

I was down for the Gorge race last summer and saw a newer elite S that had much slimmer and streamlined venturi covers. Do you think there's a worthwhile speed benefit to bother trying to sources these slimmer covers, figure out how to get my current ones off and epoxy on the new ones?

Has anybody done much gps time-trialing to tease out the differences between two -venturis, one venturi or a flush bailer?

Thanks!

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6 years 11 months ago - 6 years 11 months ago #30292 by nell
Replied by nell on topic Chunky venturi covers
My guess is that you won't notice any speed difference between larger and smaller venturi covers because it would be too small to measure. However, I suspect that smaller covers (and bullets) will lower resistance in such a way that you'll save a little bit of energy over an hour or more of paddling. I suspect that the same would be true for closeable bailers vs venturis.

I recently converted my McGregor Classic from two small venturis to a bailer. The ski feels slicker and it's obviously quieter at speed, but I can't tell any speed difference on gps.
Last edit: 6 years 11 months ago by nell.

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6 years 11 months ago #30302 by Fuyang Guy
Replied by Fuyang Guy on topic Chunky venturi covers
My thinking is that the gains would be so small as to not make it worth open boat surgery. Unless you are skilled and like to tinker.

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6 years 11 months ago #30308 by Dicko
Replied by Dicko on topic Chunky venturi covers
I have a bailer on my SEL and there is a noticeable difference in dragwhen the bailer is fully open. I would say around 0.2 kph. It doesn't sound much but after an hour of paddling 200 meters is a long way back. When the bailer is open it also improves the stability slightly. The nose doesn't get knocked around as much.

If you are worried about the drag from the venturi hoods you could add bullets to the venturis'. Red 7 invented the bullet to reduce the drag from the hood and allow them to use 3 venturis with little impact on flat water speed.

Somewhere on this site there was an article on the effects of bullets on drag.

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