I have a full-sized van with rain gutters and a rack that I can mount anywhere along the length of the roof. Someone's comment in the bow-stern tie-down exchange got me to wondering if it is better to space the rack bars apart further - or closer together? Say on a 16 ft boat - should it be support 4 ft from either end - leaving 8' in the middle? Or under the main section of the hull - rather than the highly tapered sections? How does the recommendation change for a plastic boat - exposed to sunlight/heat while loaded....it a wide spacing more or less apt to allow the hull to deform in the sun? Seems that a wide spacing might be more prone to lengthwise deformation (adding 'rocker') while a close spacing would more quickly cause 'boops' in the flatter, less rigid section of the hull around the cockpit - from the saddles or foam blocks. Thanks, K *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
On 24 Jun 2003 at 11:07, Keith Wrage wrote: > Someone's comment in the bow-stern tie-down exchange got me to > wondering if it is better to space the rack bars apart further - or > closer together? Say on a 16 ft boat - should it be support 4 ft from > either end - leaving 8' in the middle? Or under the main section of > the hull - rather than the highly tapered sections? A uniformly distributed load would best be supported under the conditions you describe - the outer quarter points. However, since a kayak is skinny at the ends and fat in the middle, you have to move the supports in towards the middle to compensate. How much could be determined thru a number of creative means, but play it by ear. Basically, you want the weight of the overhanging ends to equal the weight of the bit between the bars. If you took a Star Trek phasar and cut through the kayak at the exact centre between the bars, the two pieces would be perfectly balanced on each bar. If you put tension in the tie downs at the ends, this could allow for greater spacing since it would be like adding weight to the ends of the kayak. > How does the recommendation change for a plastic boat - exposed to > sunlight/heat while loaded....it a wide spacing more or less apt to > allow the hull to deform in the sun? Seems that a wide spacing > might be more prone to lengthwise deformation (adding 'rocker') > while a close spacing would more quickly cause 'boops' in the > flatter, less rigid section of the hull around the cockpit - from > the saddles or foam blocks. One compromise would be to locate the bars near the bulkheads, since the bulkhead provides considerable support to keep the hull in shape. This would avoid local bumps in the plastic at the possible expense of a rocker change. If you don't do this, the closer to the bulkheads you do get, the better. It sounds like you have a good, intuitive understanding of what's going on, so just fiddle till you feel comfortable. Mike *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
>If you took a Star Trek phasar and cut through the kayak at the exact >centre between the bars, the >two pieces would be perfectly balanced on each bar. The batteries are dead in my phaser - can someone loan me theirs? :o) Of course, were I traveling with a phaser, I could transport (or whatever that was called when they wigged out) myself and my boat wherever...of course, the question of high aspect ratio paddles in the absence of gravity would likely keep me near the dock... :o) Seriously, for some reason I got stupid and forgot about the support provided by the bulkheads. I like that concept. Thanks for that comment. Kirk, I agree with racks and my noggin. Luckily, my load bars are about 7'5" off the ground...and even my 6'8" carcass misses them. BUT...that brings up another point...having the bars close to the doors so I have something to stand on when putting straps in place - that would be handy too. Maybe a rack with *3* bars is the way to go.... hmmmmm.... Keith *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
Keith Wrage wrote: > Kirk, I agree with racks and my noggin. Luckily, my load bars are about > 7'5" off the ground...and even my 6'8" carcass misses them. BUT...that > brings up another point...having the bars close to the doors so I have > something to stand on when putting straps in place - that would be handy > too. I paddled for many years before I learned how easy it was to stand on the tires. > Maybe a rack with *3* bars is the way to go.... hmmmmm.... 3 bars is very nice if you can get them level. Nice even without being level, if the centre one is lower than the line connecting the other two. GaryJ *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
> > Maybe a rack with *3* bars is the way to go.... hmmmmm.... > > 3 bars is very nice if you can get them level. Nice even without being > level, if the centre one is lower than the line connecting the other two. > GaryJ > Two bars can make a very strong support especially if you can space them some distance apart. I have a Grand Voyager so I get plenty of length and the boats remain stable. It seems to me 3 bars would make for difficulties. Even if you set them dead level, your boat's profile might not be. And if you're on a group trip somebody's boat isn't going to fit right. You'd probably wind up either not having anything supported by the bar or else removing it entirely now and then to accomodate some new boat combination. Two bars would give you plenty of space for differences in curvature, three bars could restrict you. My front bar, btw, is mounted directly over the rear pillar for the front door. It's a fairly safe place to keep you from hitting your head as you get out... Joe P. *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
Joseph Pylka wrote: > Two bars can make a very strong support especially if you can space them > some distance apart. I have a Grand Voyager so I get plenty of length and > the boats remain stable. It seems to me 3 bars would make for > difficulties. Even if you set them dead level, your boat's profile might > not be. And if you're on a group trip somebody's boat isn't going to fit > right. You'd probably wind up either not having anything supported by the > bar or else removing it entirely now and then to accomodate some new boat > combination. This is why the centre bar has to be level with or lower than the others. IMHO a little bit lower would probably be better. WOn't matter if you have cradles. > Two bars would give you plenty of space for differences in curvature, > three bars could restrict you. Yup. In my comments I was assuming that few boats would curve downward relative to the ends, although with the sea kayaks prevalent on this list that would be rather different if no cradles or other holders were used. Three does let you carry shorter boats staggered (most frequent use I have seen=WW kayaks) and provides other options. Three is fine for upside-down canoes, but I don't know when it would be really necessary. (Very few people do this 3-bar thing.) I have thought about three so that I could put one further forward on my newer model mini-van. The old guttter-mounts let you choose your spacing, but that is not so easy now with rail-mounts. (Look at the spacing possibility on an Odyssey--that fronbar is very far back. One reason I did not buy one.) Racking is the most irritating part of paddling. GaryJ *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
> [Original Message] > From: Gary J. MacDonald <garyj_at_rogers.com> > This is why the centre bar has to be level with or lower than the > others. IMHO a little bit lower would probably be better. WOn't matter > if you have cradles. --But it should have to be EXACTLY the right height. Otherwise you're stressing the boat one way or another trying to tie it down. Or, conversely, the boat is constantly yanking up on that center bar. > > > Two bars would give you plenty of space for differences in curvature, > > three bars could restrict you. > > Yup. In my comments I was assuming that few boats would curve downward > relative to the ends,... But of course canoes are normally carried upside down, and even my flatwater freestyle boat has significant height difference in the middle. >> Three does let you carry shorter boats staggered (most frequent > use I have seen=WW kayaks) and provides other options. This is a possibility, especially with rack attachments for other purposes. A lot of bicycle holders, for example, require the bars be spaced exactly 1 meter apart... Three is fine > for upside-down canoes, but I don't know when it would be really > necessary. (Very few people do this 3-bar thing.) As mentioned above, probably not a good idea at all. I often carry both canoe and kayak on mine and the only compromise I am faced with usually is that the kayak has to face backward so the coaming clears the roof or the luggage rack up there. I never clamp on the bulkhead line. A friend broke the seal in that manner once... > > I have thought about three so that I could put one further forward on my > newer model mini-van. The old guttter-mounts let you choose your > spacing, but that is not so easy now with rail-mounts. (Look at the > spacing possibility on an Odyssey--that fronbar is very far back. One > reason I did not buy one.) I think it was a Volvo I was looking at which had boltholes in the window and door frames for attaching a pseudo-gutter and it could be a few feet long... Another problem besides railmounts is how much you can change vertical height. I suspect not at all... > > Racking is the most irritating part of paddling. > Oh, Yes, Indeed!!! Joe P. *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
Joseph Pylka wrote: >>From: Gary J. MacDonald <garyj_at_rogers.com> >>Racking is the most irritating part of paddling. > Oh, Yes, Indeed!!! Until a year or so ago I could say to people that the only time I ever put a hole in a canoe was on Roof Rack Reef. I was putting a tradional cedar rib-and-plank canoe on my car from the side when a gust caught me. The end of the bar hit the side just under the gunwale and right between two ribs. A small hole in the plank easily repaired but somwhat infuriating at the time. GaryJ *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
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