Slipping Genoa Sheets

[SteveIOW]

My old Gibb, single speed, non-self tailing genoa winches still work ok mechanically but the sheets sometimes slip on the winch drum when sheeting in in strong winds, This even happens when there are 4 turns on the drum and plenty of tension on the tail of the sheet. The sheets are 12mm braid on braid polyester and the winch drum about 85mm diameter. The sheets are in good condition and about 5 years old.
Would it help to roughen up the surface of the winch drum?
Any other suggestions welcome.

Steve

 

[Minerva]

That sounds like a good man-maths reason to treat your boat to nice self trailers for Christmas! you may even find a Black Friday discount to sweeten the deal. ?

 

[thinwater]

Harken used to offer a resurfacing service for their drums. Peen and re-anodize. I have heard of a few successful DIYs using either a center punch or a dulled needle scaler. Google it.

 

[Poignard]

I think I would first try washing the sheets.

 

[thinwater]

I think I would first try washing the sheets.

^^ Yes. This.

 

[Refueler]

Yep .... maybe time to clean up those sheets.

As to roughing up the winch drums ?? I suggest a good scrub with a brush and cleaning agent .... I would suspect a combo of 'unclean filled lay' of rope along with crud on the drum.

Its worth noting that rope drums work on the principle of friction ... as you increase the number of turns on the drum - you increase the friction ... they do not work by 'biting' the rope - which roughening up would possibly create.

 

[geem]

Interesting. We have a pair of Lewmar 58STs. One is original rough drum surface. One is smooth and shiny as we had it rechromed. With 5 turns on the drum we get no slip on the smooth drum.
Our original Barlow none self tailing winches were always smooth. We get no slip.
The only way we can get the line to slip on the drum when loaded is insufficient turns. 4 turns is not enough on either of our Lewmar 58ST winches regardless of the surface finish on the drum. It always has to be five turns when loaded

 

[thinwater]

... Its worth noting that rope drums work on the principle of friction ... as you increase the number of turns on the drum - you increase the friction ... they do not work by 'biting' the rope - which roughening up would possibly create.

I'm not sure how biting is different from friction, unless roughening is taken to the point where fibers are snagged and the rope is likely damaged. In that case, this is a good point. Obviously, after the drum is roughened, it must be smoothed just enough (perhaps with a wire brush) to eliminate anything sharp enough to cut a fiber.

The hold on a drum is determined by:

Load = (tail tension) x (2.72) x e^(angle in radians x coefficient of friction)

The coefficient of friction (polyester) is about 0.2-0.22 on smooth aluminum, 0.4-0.42 on a piling, and something in between on a textured drum. Dyneema on a drum is about 0.05, so expect to use 2-3 times as many turns.

As you can see, adding a turn does a lot, and the required amount of roughening is very, very small, which is why just washing the rope is a good start.

 

[Refueler]

"thinwater' ... nice to show table and equation ... but basically it doesn't change as you say yourself - the state of the rope is a good starting point.
As to roughing the drum ... I'm not a supported as I like to think the rope needs to be looked after. If we increase the 'grip' of the drum - then when we 'ease' or 'feed' the rope on the drum as in easing out that genny - that roughness can play against you.... causing the sheet to 'grab - jerk' ....
I can remember working an old Tufnol that owner had given it the 'treatment' .... that sheet used to grab and then violently release .. instead of being eased steadily.

 

[thinwater]

I was just answering the OP's question. The Harken resurfacing was not aggressive at all, just like new.

 

[Refueler]

I was just answering the OP's question. The Harken resurfacing was not aggressive at all, just like new.

If Harken do it - then I expect it to not be 'roughened' but surfaced. My reluctance is based on seeing others results firsthand and posts here that talk about roughening ....

I was not 'knocking your post' ....

 

[thinwater]

If Harken do it - then I expect it to not be 'roughened' but surfaced. My reluctance is based on seeing others results firsthand and posts here that talk about roughening ....

I was not 'knocking your post' ....

You are correct. Overdoing it could be disaster. I've always wanted to play with an old drum but I can't see buying one just to play. I do have an old winch I could mount on something.

 

[Refueler]

You are correct. Overdoing it could be disaster. I've always wanted to play with an old drum but I can't see buying one just to play. I do have an old winch I could mount on something.

I mentioned a drum I knew owner had 'resurfaced' as he put it ... the rope kept stopping and then releasing in hard strong jerks because to ease it on the drum meant really slacking of the tail tension to let it free. It was hard to control the rope properly.

 

[thinwater]

I mentioned a drum I knew owner had 'resurfaced' as he put it ... the rope kept stopping and then releasing in hard strong jerks because to ease it on the drum meant really slacking of the tail tension to let it free. It was hard to control the rope properly.

The obvious lesson is to start very slow with the resurfacing! Less is more.

 

[neil_s]

I have old Gibb non-selftailers. They are two speed ones, though. I only need two turns, even on slow speed. Try washing the sheets as suggested above - but maybe you need some new ones - five years sounds like quite a life for a rope!

 

[Refueler]

I have old Gibb non-selftailers. They are two speed ones, though. I only need two turns, even on slow speed. Try washing the sheets as suggested above - but maybe you need some new ones - five years sounds like quite a life for a rope!

5 years ??

Mine were well over 20yrs when I replaced .... that's halyards .. sheets ...

Only reason I did a complete replace job was I did a deal on a full reel of cordage ... it was prompted by the genny sheets showing signs of abrasion in the shrouds ...

 

[Poignard]

I am still using the genoa sheets that came with the boat 25 years ago!

I don't know what type of rope it is but it's lovely supple stuff.

Good enough to hang a peer with.

 

[Refueler]

I am still using the genoa sheets that came with the boat 25 years ago!

I don't know what type of rope it is but it's lovely supple stuff.

Good enough to hang a peer with.

My ex halyards are re-purposed into general use ropes ..... and still in good nick. The genny sheets though with the abraded outer sheath are restricted to non risk use ...

 

[geem]

My main halyard is Marlow Racing dyneema. It is 10 years old and has over 35,000nm on it. Still in great condition. We just replaced the genoa sheets of the same age and mileage due to some chafe spots.
Like I said in an earlier post. 5 wraps never slips.
The only washing our halyards and sheets get is rainwater.

 

[Chiara’s slave]

Rough drums… our winches are Andersen, they are bright stainless finish, polished. There are some ridges on them, but no grippy surface like you find on other brands. I was told this was to be kind to the rope. We get no slippage at all, ever, not even with naked dyneema. Another vote here for washing the sheets, and failing that buy some new ones.