Main sheet aft of boom

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Dutch01527

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My center cockpit Dehler 86 has the mainsheet running to the base of the wheel pedestal.

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Works fine for the helmsman but a real pain for other people in the cockpit as the sheet impinges on a lot of the space in the cockpit and is even potentially dangerous if it is not well controlled.

I inherited with the boat a substantial steel frame that fits across the rear cockpit athwartships and a unfitted traveller that could be mounted on the frame. The frame / traveller would be about 600mm aft of the boom end.

Are there any performance or load issues with adding a boom hanger to the aft of the boom and moving the main sheet to run down to the frame / traveller?
 
Wouldn't be uncomfortable for a centrally seated helmsman when you're going upwind?

Moving it aft wouldn't be ideal as far as geometry/leverage etc. is concerned, but it's a difficult one to get right on that boat, and I can understand your concern. On balance though, I think the designer got it about right, because moving the sheet back doesn't reduce the lassoo problem by very much.
 
I think there are significant load issues.
This is a bit tricky to convey with words rather than a diagram, but here goes....
The worst case situation is for a configuration where the traveller on top of your frame is at the same level as the boom, so that when viewed from the side the mainsheet is horizontal. Now just imagine how much force it would need for the mainsheet to pull the boom to the centreline of the boat (when the traveller is also centralised). In practise it can't do it when there is any wind loading on the mainsail. This situation puts a huge forward pull on the frame and an equally huge aft pull on the gooseneck fitting.
Now you can argue that the current arrangement also cannot theoretically pull the boom to the centreline when there is wind loading, however the crucial difference is that the loads are taken by substantial fittings in a direction that they are designed to withstand ie near vertical pull on the mainsheet's cockpit floor fitting and no fore/aft loading on the boom.
 
anoccasionalyachtsman said:
Wouldn't be uncomfortable for a centrally seated helmsman when you're going upwind?

Moving it aft wouldn't be ideal as far as geometry/leverage etc. is concerned, but it's a difficult one to get right on that boat, and I can understand your concern. On balance though, I think the designer got it about right, because moving the sheet back doesn't reduce the lassoo problem by very much.
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The cockpit is only about 6 foot long, penalty paid for a rear cabin on a 28 boat, so the helmsman tends to sit slightly aft of the wheel and can easily reach a rear aft mounted main sheet and also the jib winches. I would have to test the lasso potential. It looks like it would be better but that could be misleading.

Given that I have the frame already I might fit it ( the holes are in place but blanked off) and have a go with a temporary rope fixing on the aft of the boom. I could always switch back if not an improvement. As it is today it is very difficult even with four people onboard especially if they are inexperienced. Makes sailing a bit tense because I have to constantly monitor peoples positions and move them before a tack and especially a gybe.
 
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I would be very concerned about moving the mainsheet to aft of the wheel (if that is what you are suggesting). It would bring it into close proximity to the helmsman's head either when close hauled or even when motoring with the boom sheeted hard on the centreline. There would also be the risk of it getting caught round the wheel and/or helmsman in a tack or gybe.
 
I have my mainsheet aft. Its lower block slides on a horse which forms part of the pushpit. It is entirely satisfactory and I wouldn't want it anywhere else
 
Thanks for the replies, some very valid points. I might have caused a bit of confusion with my original description, the frame would be about 600mm aft of the boom but it is only 300mm high so still a vertical pull when the boom is amidships. I thought that a picture of what my set up would look like might help so I did a google search and came up with this:
2dqko05.jpg



The search also uncovered a old thread that I had not been able to find previously on the same subject. Lots of opinions but a number of people are using a similar set up which is encouraging: http://www.ybw.com/forums/showthread.php?253027-Mainsheet-traveller-the-best-position

I think that there would be a danger to the helmsman from the main sheet but there is a danger to crew with the current arrangement and on balance I would prefer to be at risk ( assuming I am helming) rather than novice crew.
 
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It's quite possible it could be moved, but it is good if the helm can easily reach the main to release it in a hurry if you are over powered and lose steerage.

You'll just have to see what the loads and angles look like, but the sheet loads at the end of the boom will be less than sheeted from the middle. A traveller can be useful and better than what you have for going upwind in a breeze as you can have the main on the centre line with less leach tension (more twist)
The traveller is bright right up to windward and the sheet is eased so the boom can rise (assuming you've eased the kicker)
 
If you're going to do it, then I'd suggest looking around for a (used) longer boom to get the end as near to above the traveller as the backstay permits. Get a stronger one if you can because you're going to be trying to bend the end off it - normally the load is immediately passed into the sail. That'll reduce the tension you need in the sheet by about 30%.

Marina mast racks sometimes contain bargains if you ask nicely!
 
I have sailed that particular Hummingbird, conveniently called Hummingbird, and I found the mainsheet quite awkward to use because it is behind the steering position. I would much rather have the mainsheet in front of the steering position as I find it much easier to play in that position.
 
jwilson said:
There are several hundred Westerly Fulmars in existence all of whuich have quite angled mainsheets - see https://www.yachtsnet.co.uk/archives/westerly-fulmar/t13410-ashore-beam.jpg

I think your existing Dehler boom has a eye-fitting in a track under the boom - if you could get a second eye fitted into the track right aft you could try it out, or even lash to the the boom end temporarily.
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Nice to hear from you again.Thanks for the picture of the Fulmar, that is the idea but mine would be would not be at as acute an angle. Given that the Fulmar is a much bigger, heavier boat that boom looks reasonably lightweight to me which would indicate that mine might be ok.

The track does not run to the end of the boom so I would lash a temporary fix around the boom and through an existing eye to test and bolt through a substantial boom hanger if it all works ok.
 
Many or most centre-cockpit HRs have the mainsheet aft, though probably ahead of the clew, and I haven't heard their owners complaining of any difficulty. It used to be the case that having the mainsheet at the boom end failed to counteract the bending effect of the sail, but loose-footed mains have changed this.
 
johnalison said:
Many or most centre-cockpit HRs have the mainsheet aft, though probably ahead of the clew, and I haven't heard their owners complaining of any difficulty. It used to be the case that having the mainsheet at the boom end failed to counteract the bending effect of the sail, but loose-footed mains have changed this.
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Very common in centre cockpit boats in general as it is the obvious thing to do. However it becomes less practical with a small centre cockpit boat like the OPs. As ever when you try to cram so much into such a small boat there has to be be more compromises. Either arrangement would work, just depends on personal preference as to which is the least bad - and the OP has explained it well.
 
Tranona said:
Very common in centre cockpit boats in general as it is the obvious thing to do. However it becomes less practical with a small centre cockpit boat like the OPs. As ever when you try to cram so much into such a small boat there has to be be more compromises. Either arrangement would work, just depends on personal preference as to which is the least bad - and the OP has explained it well.
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Thank you, very kind. My thinking at the moment is test it and make sure that I can handle the main sheet and traveler from the helm position without lassoing my head off. If that is ok use the aft position when I have three or more people onboard and swap it back to the original pedastal base position when single handed or two up. It only takes a minute to swop over although the sheet may be a bit longer than necessary in the original position. As Tranona stated their are compromises with a boat and this might be the best option given the choices I have.
 
A traveller system further aft and mounted higher will give less loads required on the main sheet to get the boom to centre line. The wider the traveller the better. I am guessing that you will mostly be steering from one side of the wheel or the other so operation of a main sheet that is behind the helm position would not be a problem. OP does not say if the traveller will be over the opening to the aft cockpit or aft of the opening. Further forward would be better perhaps a compromise about half way over the opening so you don't bang your head on it. You will still have significant loads on the traveller support so be careful. As said there may be some concern re pulling aft of the boom. Check the goose neck design which is usually made for some push forward (in) rather than out. Obviously from trigonometry the greater the angle of the sheet away from vertical will impose more pull on the goose neck and waste some of your force in that direction. However I think with use of a wide traveller you will need less boom vang and have less loads on the main sheet compared to pulling from the floor from a central point and of course better control of the boom when running. ie main sail well out but some load on the main sheet pulling boom down. good luck olewill
 
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The traveler will be a bout half way over the rear cabin opening. The coach roof is substantially grp and the fixings are via 3 x M12 stainless bolts through deck to a sainless plate to spread the load. The frame is heavy duty 2 inch box section and the legs have a supporting brace to take lateral loads. I am confident that it is over engineered and will take the load. Good point about he goose neck, I will look at it with new eyes.
 
I moved the main sheet to a traveller on the frame as described earlier. I am really pleased with the results. The cockpit is now clear and the sheet easily accessible by the helm. No issues when tacking and loads are lighter when hauling the sheet in. Very happy.
 
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