Mainsheet length....

Fantasie 19

Fantasie 19

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Just checking my maths...... :D

9' boom, 4:1 set up...

Hypotenuse of a 9' right angled triangle (ie. allowing the boom completely out) is 13' (it's 12.7' but I've rounded up)

So line length is 4 x 13' (which is approx. 16 mtrs in modern money - rounded up); add on some for the tail and I think 18 or 19 mtrs will do...

Good enough?
 
Sounds plausible to me. I've just bought 34 metres for a 6:1 system on a 34 footer. I measured that using an old length of worn halyard and a 100m tape measure though, none of this mathematificating :p

Pete
 
Fantasie 19 said:
Just checking my maths...... :D

9' boom, 4:1 set up...

Hypotenuse of a 9' right angled triangle (ie. allowing the boom completely out) is 13' (it's 12.7' but I've rounded up)

So line length is 4 x 13' (which is approx. 16 mtrs in modern money - rounded up); add on some for the tail and I think 18 or 19 mtrs will do...

Good enough?
Click to expand...

Yep I agree with the maths.

Don't buy rope thats too large for the blocks ... dont ask
 
Your 13ft is in the horizontal, and is one side of triangle back to cockpit sheeting point, say 5 ft below the boom? So out to boom end will be closer to 14ft x4 + 6ft tail and you need closer to 20m.
 
Stork_III said:
Your 13ft is in the horizontal, and is one side of triangle back to cockpit sheeting point, say 5 ft below the boom?
Click to expand...

I don't really know what a Fantasie 19 is, but I suspect 5 feet between top of transom and end of boom is rather ambitious. I was allowing for that factor in all the rounding-up going on.

Pete
 
Stork_III said:
Your 13ft is in the horizontal, and is one side of triangle back to cockpit sheeting point, say 5 ft below the boom? So out to boom end will be closer to 14ft x4 + 6ft tail and you need closer to 20m.
Click to expand...

Good point, but not as much as 5ft on a Fantasie 19 although the mainsheet horse is a bit further aft of the end of the boom so maybe should start with 10 ft for one side of the triangle

My best estimate would be 19m minimum.... so yes buy 20m... one end will need an eyesplice and the other a stopper knot .. they all take a bit

P6270399.jpg
Is the actual boat in question??


4:1 is surprising My mainsheet ( similar size of boat) is only 3:1
 
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Don't forget to tie a knot in the end.
I hired a Broads Yacht once.
Bearing away onto a run on Hickling broad I found out the sheet was way too short and with no knot in.
Much panicking to make sure we fid not end up aground on one of it's many shallows
 
Think the maths is fine, but personally would trust a tape measure more. Put the boom out as far as you can, measure distance to traveller, multiple by 4 then add some on for tail, splice, distance round blocks.

Also would suggest that you add a further couple of metres. You'll probably find that some points chafe/ show signs of wear. You can end for end if not too bad b,it there may be a point where you need to cut out one end as it's too far gone. If you have the extra couple of metres the main sheet is good then for several more years. If it was the perfect length already then you will need to replace the lot.
 
VicS said:
Good point, but not as much as 5ft on a Fantasie 19 although the mainsheet horse is a bit further aft of the end of the boom so maybe should start with 10 ft for one side of the triangle

P6270399.jpg



4:1 is surprising My mainsheet ( similar size of boat) is only 3:1
Click to expand...

That's me that is.... :D

Sorry - this is for a Hurley 20, my Fantasie went to a good home last October... the point about drop between boom end and transom is well made - I reckon 3 feet or so and was hoping the rounding up would account for that.....
 
Rule of thumb for boom end sheeting and 4:1 is boom length x 6, for 6:1 it's boom length x 9. So, 54' or 16.5m.
It will be interesting to see how much line you have left if you buy 20m, to test the rule of thumb.
 
I would buy 50m of thin cheap string. Fit it, measure it, then copy it. A metre too little would be catastrophic. A metre too much would be unnecessary clutter.
 
jakeroyd said:
Don't forget to tie a knot in the end.
I hired a Broads Yacht once.
Bearing away onto a run on Hickling broad I found out the sheet was way too short and with no knot in.
Much panicking to make sure we fid not end up aground on one of it's many shallows
Click to expand...

Had you the misfortune to get hooked by the falls :eek: on one of the channel marking posts across Hickling, you would have found out why Broads sailors don't tie a knot in the end.... don't ask. :o
 
Are you replacing an old one?

Guess what I'm going to suggest next.

BTW, you're not going to get your boom out at right angles

P1010660.jpg
 
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