Genoa sheet size

[neil1967]

The genoa sheets on our Oyster 406 are well past their best and need to be replaced. They are braid on braid but are 18mm diameter. Most similar sized yachts moored near us appear to have 12 or 14mm sheets, so 18mm seems to be overkill. Any reason why I shouldn't downsize to 16mm - I assume that new and slightly thinner sheets would run better, with less friction?

Neil

 

[sailorman]

i have 18mm on my Oyster 37 & have no problems with them, i would think our hedsails are similar area using Lewmar 52s

 

[pvb]

Thicker sheets tend to be easier to handle.

 

[Tranona]

Much will depend on the size of your gear. 18mm is probably overkill strength wise and probably 16mm would be a better compromise.

 

[VicS]

14mm adequate according to Jimmy Green

https://www.jimmygreen.co.uk/p/tech...ical-articles-/sheets-and-halyards-size-guide

16mm sounds like a sensible compromise

 

[Javelin]

I'd stick with the bigger dia for jib sheets.
Friction is only an issue in that first pulling in phase before you resort to the winch, even then you probably have a turn or two on the winch which you'll be fighting.
However the bigger sheet is easier to pull in your hands which will offset that friction especially if you get your timing right when you release the old sheet on a tack.
Too big a dia and it won't grip in your self tailing winch and too small and it will slip and pop out.

 

[sailorman]

I'd stick with the bigger dia for jib sheets.
Friction is only an issue in that first pulling in phase before you resort to the winch, even then you probably have a turn or two on the winch which you'll be fighting.
However the bigger sheet is easier to pull in your hands which will offset that friction especially if you get your timing right when you release the old sheet on a tack.
Too big a dia and it won't grip in your self tailing winch and too small and it will slip and pop out.

Agreed + buy matt finish

 

[Poignard]

Too big a dia and it won't grip in your self tailing winch and too small and it will slip and pop out.

Anyone know if Lewmar 34ST winches can be adjusted for different diameter sheet thicknesses?

 

[Debenair]

I disagree. On my 36 footer I have 10mm sheets in a hard finish.
All this talk about handling is a red herring. Most of the work will be done with the sheet on a winch, so as long as the strength is adequate that is all that really matters.
18mm is enormous!

 

[sailorman]

Anyone know if Lewmar 34ST winches can be adjusted for different diameter sheet thicknesses?

the newer waveguide will adjust automatically

 

[sailorman]

I disagree. On my 36 footer I have 10mm sheets in a hard finish.
All this talk about handling is a red herring. Most of the work will be done with the sheet on a winch, so as long as the strength is adequate that is all that really matters.
18mm is enormous!

The jaws of my primarys are too large for such thin string

 

[Daydream believer]

I'd stick with the bigger dia for jib sheets.
Friction is only an issue in that first pulling in phase before you resort to the winch, even then you probably have a turn or two on the winch which you'll be fighting.
However the bigger sheet is easier to pull in your hands which will offset that friction especially if you get your timing right when you release the old sheet on a tack.
Too big a dia and it won't grip in your self tailing winch and too small and it will slip and pop out.

During the manual pulling in phase there is the friction of the released sheet to overcome as well
I would go with 14mm

 

[Twister_Ken]

Friction will only be an issue with the bigger sheets if the sheet lead and turning block sheaves are too small for 18mm.

You might notice the increased weight of heavier sheets if you like to try and sail in drifting conditions - sheet weight at the clew will have an effect of the ability of the sail to fill to a good shape in very light airs.

14mm sheets are also easy to handle, so no handling advantages one way or t'other.

18mm will stand up to chafe a bit longer, if chafe is a problem.

14mm will hurt the wallet a little less.

Your call!

 

[Birdseye]

The genoa sheets on our Oyster 406 are well past their best and need to be replaced. They are braid on braid but are 18mm diameter. Most similar sized yachts moored near us appear to have 12 or 14mm sheets, so 18mm seems to be overkill. Any reason why I shouldn't downsize to 16mm - I assume that new and slightly thinner sheets would run better, with less friction?

Neil

I cant imagine a load / strength problem if you went to 12mm. Instead the issue is comfort in handling and what will fit in the self tailers.

18mm must be lovely to grip!

 

[Simondjuk]

Lewmar state the line diameter range for both Ocean 54 and Evo 55 self-tailing winches as being 8mm to 16mm, so 18mm is almost certainly beyond the range for a smaller winch such as the 52 which is no longer listed.

The use of lines too large for the tailer will deform the springs, which is probably why Sailorman's 52s won't grip 10mm line after having 18mm sheets used in them.

18mm is massive for a boat in the 30s or 40s of feet anyway and more suited to boats carrying headsails covering the 60 to 120 m2 range.

I can't imagine that having the weight of two 18mm sheets hanging form the clew does much for the set of the headsail of a 30 something foot boat in light airs either.