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Old 14-02-2009, 18:24   #1
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Moving the Main Sail Traveller

Hi All,
I am thinking about moving the mainsail traveler from the cockpit to above the companion way hatch, primarily to increase a little space. It doesn't seem to be too big a project to do this, but I wonder about changing the dynamics of the boat. Anybody have any insight?
Hank
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Old 14-02-2009, 18:31   #2
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Hank,

A couple of issues:

Moving from sheeting at the end of the boom to near the center puts much bigger bending loads on the boom itself, and this can be a problem if the extrusion (I assume that it is alloy) is not stiff enough.

Also, you loose some leverage in pulling the boom down when closehauled, and this makes it hearder to keep excess twist outta the main. Only means that you need a bit better mechanical advantage in the mainsheet.

All this said, though, there are many center-boom boats out there, and it is nice to get that mess outta the cockpit!

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Old 14-02-2009, 18:41   #3
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Good thread. I am actually thinking of doing the same thing. Somebody told me it would actually make the main sail easier to control, since I don't have a boom vang.

The main reason I was thinking of doing it, though, is so that I could make the cockpit fully-enclosable with a dodger-bimini combination.

I'd love to hear more opinions on this. For my model boat (Bristol 34 masthead sloop), I have seen both positions. I assume that the original configuration was the cockpit.
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Old 14-02-2009, 19:16   #4
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bad idea

Moving the traveler aft is generally fairly safe. Moving it forward might necessitate a heftier boom, heftier running rigging, greater purchase on the mainsheet block system, et cetera. We're talking about significant financial investment in order to degrade the current system in terms of performance.

If you can remember back to high school physics, think in terms of mechanical advantage, and you'll probably talk yourself out of the idea.
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Old 14-02-2009, 21:15   #5
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Check a columbia owners website if there is one?
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Old 14-02-2009, 21:56   #6
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I reckon its a great idea!!!!

We have the main sheet on the cabin roof and its is marvellous! I would never ever have a boat with it in the cockpit again - and remember I'm from a racing background!

You don't need a hefty boom! Ours is a Beneteau and the boom definitely ain't heafty

The ceiling of the coach roof doesnt seem to be over supported.. like theres no roll bar etc. I think the traveller spreads the weight.

I never use the vang much with this system certainly not like I would use it on a cockpit mounted mainsheet.

When people say stuff about not being next to the helmsman it doesn't realise that cruisers are mainly using the autopilot and its more convenient to have it next to the reefing lines etc

If I was moving it from the cockpit I would certainly have a suitably qualified person, or the original builder, give advice. But then go for it!

You'll love you new cockpit!

Mark
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Old 14-02-2009, 22:26   #7
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Hank,
You may want to read this thread as well for a better understanding of mid boom sheeting and possible problems.

Mid-Boom Sheeting And A Broken Boom
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Old 15-02-2009, 00:17   #8
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I can't see how a mid boom mainsheet will break a boom as most, unlike end of boom, spread the blocks along a meter or more of the boom.





Then theres the vang.... then the sticky-up-bitty.

The only unsupported part is between the boom end and the last block whcih, on ours, is just aft the second reef. In other words if you have a second reef in you have a main sheet blow very close to it.

If your boom breaks when you don't have any reefs in the go back to Sailing 101 cos a 10kt breeze won't break it!
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Old 15-02-2009, 00:53   #9
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I think it would be an improvement to the cockpit for sure.

But consider the loads and an accidental jib...its not the same as normal sailing loads.

As Mark said you'll be able to spread some of the load with multiple attachment points under the boom.

But if you need to do a bridge to get over the companionway's doghouse you may have concentrated tension loads at the ends of the bridge.

There will always be ways to make it work but some of these considerations should be taken.
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Old 15-02-2009, 05:17   #10
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Thanks for all your advice. Definitely something I will put considerable thought into. I will need a bridge, so there will be concentrated points of contact at each end. So, something else to consider.
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Old 15-02-2009, 06:26   #11
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another consideration for the movement of mainsheet attachment point to centre of the boom is the type of mainsail you have.

If you have a loose footed sail or a shelf foot, then there are significantly different loads on the boom. Attaching the traveller to the middle of the boom with either of these options will definitely put the boom under a lot of extra stress.

I changed to a loose footed main, and noticed that the kicker alone was adding a significant boom bend, whereas before this was not an issue.

I would definitely be talking to the boom manufacturer for advice.

The concept of main sheets not being a problem in the cockpit is a good one, especially with small children.
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Old 15-02-2009, 06:56   #12
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I've had sailboats with the mainsheet at the end of the boom, and attaching to the transom, from a bit forward of this attaching to a traveler, spanning the cockpit, from forward of center and attaching to a traveler just in front of the companionway hatch and from even farther attaching to a cabin top traveler. On one boat, the arrangement had been changed from transom attachment to a traveler spanning the cockpit in front of the wheel and still used the original boom, traveler and mainsheet, with no notable problems during the 8 years I owned the boat.

Of these four, my favorite is the cabin top option. My least favorite is the traveler spanning the cockpit. During rough weather I felt this presented a serious safety hazard and was a nuisance all the time. I also don't like the way this arrangement limits bimini coverage which is very important to me when sailing in the summer. There may be some mechanical reasons to not put the traveler on the cabin top, but this must be weighted against the advantages of doing so, and the ability to offset the disadvantages.

While, people make good points about the differences in mechanical advantage and leverage, there are many, many examples of cabin top instillations that work well. However, I agree, it's important to make sure, your boom and other rigging can handle this, since the boat wasn't designed with this in mind.

I'll also note that the case quoted above was not due to someone changing the location of their mainsheet and traveler. There was a finding of corrosion in the boom and the owner admitted tightning the topping lift under sail, creating torque where the fitting holes were drilled.
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Old 15-02-2009, 08:02   #13
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I wonder about the effect of multiple pick points on a mid-boom arrangement vs. a single pick point on the end boom rigged mainsheet. My mid-boom mainsheet has three bales on the boom, which spreads out the load, and I believe greatly reduces the possibility of failure, as opposed to a single mid-boom pick. We have also used a heavy duty Garhauer traveler and bridge with large SS backing plates. We feel pretty safe with this combo...
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Old 15-02-2009, 08:44   #14
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Well, after reading carefully through this thread, I've decided that...

I'm still not sure.

I'm now leaning more toward not moving it out of the cockpit, though.
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Old 15-02-2009, 11:43   #15
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Actually, you do not have to have a heavier boom because you are spreading the load over a much larger area at 3 points. Assuming you are moving it forward 1/3 up the boom, you are increasing the load that much also. However...it will require a greater mechanical advantage for sheeting thus a higher ratio of block and tackle will be needed. Generally, just copy what ever anyone else has on the dock of a similar sized vessel.
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