Which way up?

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Jonathan Theobald
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Which way up?

Post by Jonathan Theobald » Sat May 31, 2003 6:49 pm

The ASSC website has a page on kayak care where they recommend putting boats on roofracks keel up (as opposed to on a gunwhale which is what I've preferred), and with hatches off.

Anyone know the logic there - and whether it really matters?

ASSC offers no reasons.

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Mark R
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Re: Which way up?

Post by Mark R » Sat May 31, 2003 7:29 pm

Oblique.


-----------Mark Rainsley

Jonathan Theobald
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Re: Which way up?

Post by Jonathan Theobald » Sun Jun 01, 2003 7:59 pm

You wouldn't care to be more specific?

That's too cryptic for me.


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MikeB
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Logic

Post by MikeB » Sun Jun 01, 2003 9:44 pm

Well, this is the stuff on the NDK site right?

Lets apply some logic - hatches "Off" - makes some sense from the perspective of avoiding pressure build-up in the heat, as mentioned elsewhere on the site.

"Upside down on a roof rack" (unless in a purpose built cradle) - aerodynamics? The hull would tend to lift with air-pressure because of its slight upturn if placed deck-up. Mind you, that logic is badly flawed with a boat with a low rear deck seeing as how that will present an up-angled bow section to those 80mph winds.

Less chance of damage to the boat hull? The round section certainly bends nicely when subject to a good tying down. The flat rear deck and flatter front deck section would maybe distort less?

I can see the arguments for storing upside down, with no hatches. Ahhhh - if the hatches ARE off when travelling, and the boat ISN'T upside down then it's going to get full of water when left parked in the rain! Or, could it be that "white (hull) bits absorbing 20% less heat than dark colored deck"??

Other than that, I can't see the benefit.

I'll stick with my nice KCS cradles and as a hull on its side presents the strongest possible profile against the tension of straps/ropes (egg-shape) then thats the way I carry a boat on a rack without a J cradle of some sort.

As to removing hatches when storing, that certainly is a factor for a boat stored outside - ultraviolet degradation. As to removing while travelling I'm sticking with them staying on the boat. One less thing to lose/forget and they are tied on anyway.

Also intrigued re the cryptic "oblique"!

Mike.

Steve B
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Re: Which way up?

Post by Steve B » Mon Jun 02, 2003 10:58 am

I think this is much less of an issue than some people make it out to be, but there is a case for upside down:

Keeps the rain out for one thing.

Straps spread the load, they should be on the hull; roofbars create pressure points, less of a problem on the deck. If you think it matters, that is.

The aerodynamics thing is a bit of a red herring I believe. You could in fact create more lift with an upside down boat, because of the aerofoil effect, but either way turbulence, crosswinds and so on are at least as important. Fixing the boat securely is the solution, not calculating the aerodynamics.

For anyone who didn't get Mark's answer, I would venture to suggest he means 'any way up, it doesn't much matter'. Which is good advice.

Steve B.

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sub5rider
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Re: Which way up?

Post by sub5rider » Mon Jun 02, 2003 11:45 am

My Onion sits on the roof bars on its left side, but with the right side of the hull against the upright, so when you look at it fore & aft it's about 40deg off vertical. Friend's Sirius, with a much more pronounced "V" won't do this and has to be carried "vertical"

I had always assumed that hulls are stronger than decks, so yes my straps go over the decks but the main contact points are on the hull.


Always travel with the hatches on * - and cockpit cover - as these areas will generate significant drag. Exeriment: put 2 ww boats on roof either side of uprights cockpits facing out. Drive on motorway. Turn boats cockpit to cockpit. Drive. Feel the difference - esp in low powered car, eg BX diesel.

*P&H boats (well mine anyway) have a pinhole in each bulkhead to allow pressure relief

Do we all tie our boats' ends to summat when travelling ?
I do, but with no tension in the cord, as a "just in case"



Nigel, aka Sub5Rider, Onioneer

Jimbo
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Exploding hatch cover

Post by Jimbo » Mon Jun 02, 2003 2:06 pm

Last year in the really hot spell at the beginning of May, we stopped in Fort William about lunch time en route to Uig. My pal's boat was dark blue, deck up on a V cradle. When we got back we found a spare rubber hatch cover lying in the car park about 50 feet from the car. As there were no other kayaks about my pal kept it as it was the same as his own.

When we were unloading at Uig for the ferry to Tarbert my pal was really upset to find that someone had pinched his front hatch cover. It was really lucky he had found a spare....

My Sirius has a tiny bleed hole in the bulkheads so mine hadnt been "stolen".

Must have made a hell of a bang though!

Jim

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andy
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cockpit cover

Post by andy » Tue Jun 03, 2003 12:47 pm

I lost a very nice Kogg life jacket after a cockpit cover blew off somewhere on the road from Ullapool to Elgin.
:(
Andy

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sub5rider
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Re: cockpit cover

Post by sub5rider » Tue Jun 03, 2003 1:22 pm

Well at least it was AFTER you trip ?

Personally I never carry any kit in any boat - it becomes too easy to overload the roof-rack...
Nigel, aka Sub5Rider, Onioneer

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Douglas Wilcox
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Never overload your roofrack.

Post by Douglas Wilcox » Tue Jun 03, 2003 4:55 pm

Nope, I never overload either...
www.gla.ac.uk/medicalgene...cowall.jpg
Douglas

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MikeB
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Overloading

Post by MikeB » Tue Jun 03, 2003 6:50 pm

Only 3?

The guy who runs SPS in Scotland carries 6 on an Audi IIRC.

My personal record for overloading madness was 13 GP river boats (Europa's and the like) on a Landy. We increased the width of the r/rack a bit with a few hefty planks and stacked the things in a pyramid.

We then had to drive past the local police station 4 times a day with a full load of bodies in the thing as well.

Scout Camp in Ireland - which explains the relaxed attitide of the Garda who waved to each each time we passed !

Mike.

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