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Load rating on swivel cam or "stepping straps"
http://www.hobie.com/forums/viewtopic.php?f=15&t=34540		 Page 1 of 1
Author:  JJ [ Mon Mar 21, 2011 8:25 pm ]
Post subject:  Load rating on swivel cam or "stepping straps"
Anyone know the load ratings on the jib swivel cams on the FX or similar?

I can't find any info on them. Part #50009 on page 22 of catalog?

Or, opinions on whether jib swivel cam can stand much racking and stress from a rope that holds the mast while stepping?

The rope runs from end of forestay to eye bolt on mast stand then back to jib swivel cam then to rear of the tramp. I am pulling on the rope with left hand while pushing mast up with right hand.

Had considered eyestraps that I see called "stepping straps" on another brand of catamaran.

Sorry for the long post, but the FX has a busy front crossbar and NO standard cleats on it or the mast. (The sail hooks into the top of the mast.) I am a bit freaked about putting another rivet in the crossbeam... or popping the swivel cam off too. There is a lot of pressure on the swivel cam.

Also, am using a 3:1 pulley setup with the rope...

Yep, this is another mast stepping post.

edit: cut images for band-width reason
Author:  srm [ Tue Mar 22, 2011 9:35 am ]
Post subject:  Re: Load rating on swivel cam or "stepping straps"
Are you going to try pulling the mast up using the rope in one hand while lifting the mast with the other hand? Unless you have at least three hands, that seems like it would be incredibly awkward to me.

Are you strong enough to raise the mast by hand? If so then I'd ditch the 3:1 system - it's just more line to have to deal with. If you're not strong enough to raise the mast by hand, then you should really consider either having a helper get the mast up for you or investing in one of the gin-pole mast step systems.

The way I've always solo stepped the mast is to simply tie a line to either one of the trap handles or to the main halyard, then lead the line through a block on the trailer mast stand, and then back to one of the jib cleats (or downhaul cleat if you don't have a jib). Fully raise the mast, pull the slack out of the line and cleat it, then jump down and pin the forestay.

In any case, I think the cleat would be plenty strong for whatever you're planning to do.

sm
Author:  JJ [ Tue Mar 22, 2011 10:27 am ]
Post subject:  Re: Load rating on swivel cam or "stepping straps"
Quote:
Are you going to try pulling the mast up using the rope in one hand while lifting the mast with the other hand? Unless you have at least three hands, that seems like it would be incredibly awkward to me.
It might be. I have seen people putting a mainsheet between their teeth to take up slack. However, with this setup, not if I bungee a loop at the rope's end to the mast. It stays within reach and it is yanked down after use.
Quote:
Are you strong enough to raise the mast by hand?
Yes, I just don't like rodeo adventures. Plus the FX tramp, like the Tiger's, is saggy. This takes some load off the tramp.
Quote:
I'd ditch the 3:1 system
It is not that much line. The 3:1 was an inspiration from Matt actually, at the 5:50 mark.

[youtube]http://www.youtube.com/watch?v=ca_n9F7pwuY&feature=related[/youtube]

The block and tackle does what a block and tackle does -- it makes it easy to pull.

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...investing in one of the gin-pole mast step systems.
Been there. May go back there, not yet.

Quote:
The way I've always solo stepped the mast is to simply tie a line to either one of the trap handles or to the main halyard, then lead the line through a block on the trailer mast stand, and then back to one of the jib cleats (or downhaul cleat if you don't have a jib). Fully raise the mast, pull the slack out of the line and cleat it, then jump down and pin the forestay.

In any case, I think the cleat would be plenty strong for whatever you're planning to do.
Essentially what I am doing. Except using the pulley setup to ease the load up. There are no standard cleats on the FX. Nada.

There is the jib swivel cam cleat that connects to the crossbar by a swivel on a plate that has three rivets and for which I can find no max load info. IT is what I am concerned about. Hate to tear it off and then say, "Well, that didn't work so good." Guess I should have used a fairlead or eyestrap or bullseye...

Sorry, not trying to be a wiseass. Just asking questions to spare future expense. I'm just cheap!
Author:  srm [ Tue Mar 22, 2011 10:48 am ]
Post subject:  Re: Load rating on swivel cam or "stepping straps"
Couple thoughts-

First, if you're leery about mounting another cleat on your boat, or you're not sure of the load rating of the cleat on your crossbar, then take the boat out of the equation. Mount a cleat on your trailer somewhere, perhaps on the forward mast stand.

Second, the cleat you're talking about is almost certainly strong enough, especially if you're planning on using a 3:1 reduction. Stainless steel rivets are good to roughly 500lb minimum in shear, times three rivets, means theoretically you should be good to 1500lb. Even a safety factor of half would give you plenty of margin.

Third, again, if you're able to raise the mast by hand, it's almost always the best method. It's quicker, doesn't require a lot of extra lines and gizmos, and doesn't rely on cables and fittings to support the mast. You're not going to hurt your tramp by manually raising the mast, the tramp is designed to take the load.

sm
Author:  Karl Brogger [ Tue Mar 22, 2011 4:22 pm ]
Post subject:  Re: Load rating on swivel cam or "stepping straps"
With the FXone, and the halyard cleat on the front beam I would tie the halyard off somewhere handy on the mast, (I think I tied it off to the turnbuckle for the diamond wires), then up through the block at the top as per usual.

From the block I ran it through the loop that is on the hull, (I think I did starboard side, as that was the side of the mast the cleat is on), then back to the cleat.

Lift the mast with adequately loose shrouds, reach down and pull the halyard tight, then cleat. Presto, its holding the mast, you can jump off and hook up the forestay, release the halyard in the cleat, and tension your rig as per usual.


Rigging a boat on a trailer blows.


JJ wrote:
Yes, I just don't like rodeo adventures. Plus the FX tramp, like the Tiger's, is saggy. This takes some load off the tramp.


Its only saggy if its loose. Tighten it up.
Author:  JJ [ Thu Mar 24, 2011 9:30 am ]
Post subject:  Re: Load rating on swivel cam or "stepping straps"
Quote:
then take the boat out of the equation
Like that idea!

Quote:
cleat you're talking about is almost certainly strong enough
The main question. As general rule, most high stress attachments to crossbar are either mounted on a plate or a track. Like traveler car and track. It's always attachment points. Where's an attachment point for something? Kinda suspicious when manufacturers leave blank the max load ratings.

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You're not going to hurt your tramp by manually raising the mast,

Quote:
Its only saggy if its loose. Tighten it up.
Not afraid of hurting it. More wary of shaky footing. You guys spoiled by tight 16 and up tramps...

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Rigging a boat on a trailer blows.
Yep, but not having a nice soft lawn to sit the boat on does worse. How does handling the F16 mast compare? (Can hear advertising now... F16 mast can be raised with drink in one hand, mast in other... :lol:)
Author:  srm [ Thu Mar 24, 2011 10:51 am ]
Post subject:  Re: Load rating on swivel cam or "stepping straps"
Quote:
Kinda suspicious when manufacturers leave blank the max load ratings.


Not really. Hobie mounted the cleat on the boat to serve a specific purpose (be it a cleat for a sheet, halyard, downhaul, or whatever). They have (or at least should have) proven through their engineering and testing that the strength of the cleat mounting is adequate to perform it's intended function.

You're using the cleat for something other than what it was intended. The onus is on you to figure out if it'll work or not.

sm
Author:  JJ [ Thu Mar 24, 2011 12:33 pm ]
Post subject:  Re: Load rating on swivel cam or "stepping straps"
No implying that Hobie did not do proper testing.
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