Jib ratchet block selection

Moderator: GreenLake

Jib ratchet block selection

Postby oian » Wed Aug 03, 2016 10:15 pm

I'm upgrading my 1978 DS II, and am going to be using a ratchet block on the Jib sheet. I ordered and got a Harken 40mm carbo ratchet block. It doesn't seem to hold very well, It doesn't seem to make much diference whether the ratchet is turned on or off. The jib sheet is 3/8", the maximum size listed for the block, but it may be too large to fit into the ratchet on such a small diameter sheave. The only other ratchet block I've ever used is the one left over from my once owned Hobie 16, which block stack, by the way, in a de-tuned version, is going to replace the stock DS system . I tried that ratchet block from the Hobie on the DS II sheet and it held quite well (it's way too large and heavy for this purpose!). The Harken block has five facets on the sheave, while the block from the Hobie has multiple grooves. Would a 55mm block work better? Could another brand, Ronstan for example,(it's claimed to hold better) be a better choice? The 4mm block seems quite small and would possibly be more an appropriate for a smaller line. My wife, The Jib crew (Her first time in a sailboat was last Sunday), Would really appreciate your help. I'm going to put a cam cleat on the center board cover, but a functional ratchet block would also be very useful.

Thanks for your help in this matter, John
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Re: Jib ratchet block selection

Postby klb67 » Thu Aug 04, 2016 11:25 am

I upgraded the stock jib controls to the Ronstan 40 mm auto ratchet orbit block and harken cam cleats on the CB. I have 5/16 sta set jib sheets, in blue. I think the combination works quite well for my inland lake sailing. My 8 year old son is just able to sheet in while sailing in some heavier winds (for me).
1976 DSII - #8039
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Re: Jib ratchet block selection

Postby GreenLake » Fri Aug 05, 2016 3:09 am

I believe my jib sheets are 3/8" (see the "Rope for Various Lines" thread). They have a rather smooth cover, because the rope I used was a leftover bit that was meant for some other purpose. So they would be a challenge for any ratchet block. The Ronstan 55mm blocks I fitted work quite well.

I use the same block for my main sheet, which is also 3/8" (albeit of a more appropriate construction for the purpose).

In both cases, the line only goes around 90 degrees, but the blocks hold fine. I was just out today, winds gusting to perhaps 12-15, and ended up never cleating the main (except downwind).

If a ratchet block won't hold, you might try another line (different diameter, different construction) to see whether that makes a difference; certainly need a good match of diameter. But ultimately, some blocks just hold more tenaciously.
~ green ~ lake ~ ~
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Re: Jib ratchet block selection

Postby K.C. Walker » Sat Aug 06, 2016 2:02 pm

I think that auto ratchets are ideal for jib sheets because they run free for tacking when you release them. I have had both 40 mm Ronstan auto ratchets and 60 mm Allen switchable ratchets. I use 7 mm New England Ropes Bzzz line which holds very well in either ratchet and is very comfortable… and it doesn't tangle. I have not tried them but I would think that the 55 mm Ronstan auto ratchets would be a very good choice.
KC Walker, DS 1 #7002
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Re: Jib ratchet block selection

Postby tmittner » Tue Jun 20, 2017 11:00 am

I have Harken 40mm ratchets with New England 5/16 sheets I got from D&R Marine. The sheets went to Harken extreme angle cam cleats on my center board trunk. The ratchets seem to hold OK, but I thought trimming in the jib was harder than it needed to be. I took a page out of Greenlake's book and removed the captives on the cam cleats making the jib easier to trim and just lowering the sheet into the cam cleat (using my foot if necessary). I'd say 55mm ratchets might be worth the extra expense. Not having captives on the centerboard cleats has an added bonus on my DS II as it has no thwart, so you can throw the sheets out of the way opening up the cockpit. Ropes, ropes, and more ropes!
Tom
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