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Re: Other: I made aluminium cradles
By:Les Cheeseman
Date: 1/31/2011, 9:25 am
In Response To: Re: Other: I made aluminium cradles *PIC* (Ian Johnson)

: Hi there

: I decided to have a go at building my own custom cradles, but using
: 1" x 1/4" strip aluminium instead. It worked really
: well. Each cradle is rigid and very strong. In my case, I was
: able to bolt it through the rack, because the rack crossbars are
: thick enough to accommodate two holes and I could slide an
: insert into the crossbar tube to support the bolts.

: Each cradle is in two parts - a piece tailored to fit the hull, and
: then a J shape outside that to hold it rigid. Bending the
: aluminium was easy using a vice. Three stainless steel bolts
: hold it together, and also bolt it to the crossbar.

: It cost about NZD20 for a 3 metre strip of aluminium, plus some
: stainless bolts. I fitted a plastic clip onto a short webbing
: loop, with a bungee to haul over the kayak, and used contact
: adhesive to add strips of minicell foam onto the aluminium to
: protect the hull. The angled cradle makes it easy to put the
: boat on the rack myself, leaves space for more, and accommodates
: the J shape which is integral to the strength of the cradle.

: Make sure you tether front and back as well though. I did this
: using John Caldeira's nifty idea of adding a webbing loop on
: either side of the car's bonnet (hood), for a tether up to the
: bow, and a further tether from the tow ball to the stern.

: For the trip home from our holiday, I took a "she'll be
: right" attitude because some idiot had pinched my front
: tether. I drove home without it. After 100km of open road
: driving, we hit a very strong cross wind while crossing a bridge
: ... and the rack exploded. The cradles held fine, but the force
: of the crosswind sheered the bolts clamping the crossbars to the
: car's roof rails, and the whole assembly took off. Fortunately I
: still had it tethered at the back, but the kayak took a bit of a
: hit. A lot less damage than I would have expected (tip of bow
: was crushed, and a few scratches where the kayak was pivoted on
: the tow ball-mounted bike rack - it bent a 1" pipe on the
: bike rack! By rights the kayak should have snapped in half ...
: phew ...).

: I was most embarrassed to have had an unsecured load though. So
: many people transport kayaks without bow/stern tethers. So
: please do learn from my mistake!

: Regards, Ian

Hi Ian.
Two observations.
1. Mounting your boats on edge shows off the deck stripping well but it also
presents the largest possible surface area to a cross wind.
2. Lengths of 1"x1/4" ally at a foot or two may feel stiff when you try to bend them by hand
but in reality it is not stiff or strong and once an axial twist has started it rapidly becomes even weaker!
Given the windage area and leverage on the length of a 17 ft boat, I am not realy surprised at your incident.
Given the cost, TLC and blood sweat and tears that go to make a boat, I think I'd try to find something
a little more rigid and robust to carry it/them on, even though front and rear tiedowns do help.
The expression "Spoiling the ship for a 'hapeth of tar " springs very readily to mind!
Les C.

Messages In This Thread

Other: Racks
Paul R -- 1/28/2011, 9:52 am
Re: Other: Racks
Al Edie -- 1/28/2011, 10:39 am
Re: Other: Racks
Bill Hamm -- 1/28/2011, 11:11 am
Re: Other: Racks
Les Cheeseman -- 1/28/2011, 12:04 pm
Re: Other: Racks
Dean -- 1/28/2011, 12:55 pm
Re: Other: Racks
Scott Shurlow -- 1/29/2011, 12:36 pm
Re: Other: I made aluminium cradles *PIC*
Ian Johnson -- 1/30/2011, 6:33 pm
Re: Other: I made aluminium cradles
Ian Johnson -- 1/30/2011, 6:36 pm
Re: Other: I made aluminium cradles
Ian Cummins -- 1/30/2011, 10:47 pm
Re: Other: I made aluminium cradles
Niven Paine -- 1/30/2011, 11:06 pm
Re: Other: I made aluminium cradles
Ian Johnson -- 1/31/2011, 1:29 am
Re: Other: I made aluminium cradles
dave g -- 1/30/2011, 11:16 pm
Re: Other: I made aluminium cradles
Bill Hamm -- 1/31/2011, 12:25 am
Re: Other: I made aluminium cradles
Les Cheeseman -- 1/31/2011, 9:25 am
Re: Other: I made aluminium cradles
Ian Johnson -- 1/31/2011, 7:47 pm
Re: Other: I made aluminium cradles
Bill Hamm -- 2/1/2011, 1:06 am