Overhead mainsheet gantry, rough cost?

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jonjo

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What would the likely cost be (to the nearest £200) of getting an overhead main-sheet gantry fabricated? The yacht in question is a 35' mono, fairly narrow cockpit by modern standards, 400 sq ft mainsail, high cockpit coamings so the vertical raise of the gantry would be less than 4ft.

For the purpose of this question design and fitting would be a separate estimate.
 
Main sheet

Just as a suggestion and much cheaper a friend has a 32ft mono with dodger and mainsheet on a track ahead of the dodger. Very inconvenient.
We found it easy to rerun the mainsheet so that from the tackle forward of the dodger the operating tail of the tackle went aft along the boom to a point above the cockpit where it turned down with a block with a cleat. The tail dangles down and the mainsheet is adjusted from overhead but all very similar to what you will end up with. consider... regards olewill
 
The simple answer is I haven't a clue. Mine is made from an Aluminium box section welded together, so you'd need to find a good Aluminium fabricator. I reckon you'll need to concern yourself with the design first in order to know what spec you want to be quoted for.

There are pros & cons with a gantry and and the odd thing that is a nuisance but I can leave that till you ask about the design details.
 
If you're going to ask for a price, you should at least provide a sketch of what you're expecting.
At the moment you're going to get suggestions of what other people imagine you are thinking of.
So decide : will it ever have ----> mainsheet track, solar panels, radar, navtex/ais etc. aerials, windmill, bimini, steadysail, davits or anything else you can think of , attached/integrated? If "no", then is sheeting forward of the sprayhood feasible (as mentioned above) or integrated into a more robust sprayhood frame.
Take a pic and photoshop it on, to give the fabricators a clue.
 
Billjratt said:
If you're going to ask for a price, you should at least provide a sketch of what you're expecting.
Click to expand...
I have in mind a Malo type arch but for phase one there would be no integrated GRP look or spray hood connection.

http://newimages.yachtworld.com/resize/1/95/39/3839539_20120130080335_1_LARGE.jpg

yes - mainsheet track ( and as wide as possible ).
no - solar panels
no - radar, navtex/ais etc. aerials, windmill

In more detail:

  1. Forward rake of about 15 degrees.
  2. 6' wide.
  3. 3.5' high side.
  4. Attractive curve between vertical and horizontal sections.
  5. 3' to 4' length of mainsheet track.
  6. Some integral pulley wheels to lead mainsheet down to coaming level cleat.

Metalwise:

Main structure would be two continuous hoops of alloy tubes (say 2" ?) braced by horizontal cross joins at 18" intervals and bridging a 10" gap between the two main hoops.

Solid plate top between the hoops for mounting the main track.

My cockpit coaming is unusually wide so to help brace the structure from gybe type forces I could fit an extra vertical support 6" inboard of the vertical section of the forward hoop.
 
dt4134 said:
There are pros & cons with a gantry and and the odd thing that is a nuisance but I can leave that till you ask about the design details.
Click to expand...
One thing that I cannot picture in detail is how to lead the mainsheet off the arch down to the deck. Later Malos seem to lead the mainsheet forward to the gooseneck then right back to the cockpit via the coachroof.
 
Sailed a Malo, and the traveller wasn't easy to use because of the friction inherent in bringing the traveller lead down. Had to resort to standing on the cockpit seat and shoving the traveller over. Friction is your enemy, so look at ways of doing things that minimise it. Malo hadn't succeeded.
 
Twister_Ken said:
Sailed a Malo, and the traveller wasn't easy to use because of the friction inherent in bringing the traveller lead down. Had to resort to standing on the cockpit seat and shoving the traveller over.
Click to expand...
Your concern is noted, thank you.

My current thinking is a large diameter pulley either end of the horizontal section of the arch leading the mainsheet car control lines downwards inside the arch supports to a jam cleat mounted about half way down the arch pillar.
 
Don't the US Hunters have them? with the backstayless rig. Worth a look for ideas. Biggest one that comes to mind is your bracing for side loads. Diagonals might take up a lot of room.
 
jonjo5 said:
One thing that I cannot picture in detail is how to lead the mainsheet off the arch down to the deck. Later Malos seem to lead the mainsheet forward to the gooseneck then right back to the cockpit via the coachroof.
Click to expand...

I've got the German system, so led forward to the gooseneck, down the mast, under the side deck then out to a winch (a single winch unlike modern German system mains). Lots of friction with so many blocks.

No traveller on the gantry, which isn't as bad as it might seem as you can control twist reasonably well with just the last few inches of sheeting as the fixed point and boom are very close when the main is sheeted in.

It has a shock absorber for gybing - something I reckon you'll have to think about in calculating the strength of yours.

There are issues with the blocks touching each other when sheeted in hard. Also wear where the blocks contact the gantry when the main is right out.
 
May I be the first to offer a figure?
£500 rough alloy, £1000 really elegant from
Someone who has a marine understanding.
What about buying cheek blocks and new/recycling traveller etc? All add-ons
 
If it is useful as a guide, my arch is in 10cm OD thick-wall stainless steel with a track mounted on top.
I know it is not original because I found track mounting bolt-holes in the coachroof.
The sheeting consists of a double block on the boom, a triple on the arch-track with the sheet dropping to a single block and becket/jammer on a swivel on the coachroof.
I guess the main money would be in the stainless steel for the arch itself.
If pics help, let me know and I will take some next time I am at the boat.
 
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