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rachet block

LaLi

Well-Known Member
The difference between those two is really only the holding power - the Harken has 10:1 and the Ronstan 20:1, so the latter is twice as "grippy" or "sticky". Neither is necessarily "better". There seems to be increased demand for higher grip, as Harken has now introduced 15:1 and 20:1 versions of their 57 mm ratchets. They don't look very technically innovative, though.
Harken Sailboat Hardware and Accessories
Harken Sailboat Hardware and Accessories

The Ronstan is less expensive, so that would answer the "better to buy" question.

If your sheet is less than 8 mm thick, I'd go for a 40 mm Ronstan (RF 46100).
RF46100 | Ronstan Sailboat Hardware World

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I have the Ronstan 55 and highly recommend it due to its grip. It is the metal cutouts in the side that do this. Some have said that these can wear more on the sheet but I haven't found that.

I upgraded from the cheap Nautos because the Nautos wasn't helping at all due to slipperiness. I examined the Nautos to see if it could somehow be modified to make it more grippy but couldn't see an easy way. Might have just used the hook in that case.

I don't know what the 10:1 or 20:1 means in this case, might just be marketing. Ratios only make sense to me in the context of a pulley system, not a single block.

One other very important thing:

It is also important how your block is mounted. If your block is mounted like the first picture, and you are pulling down into the cockpit, then only a small surface area of the line will actually be contacting the block. Whereas if you have a combo or system where the cleat is up higher, it will allow more line to contact (thus better grip) I wish i had realized this before mounting, but still works pretty good.




On The Cheap.jpgSunfish mainsheet block and cleat 003.jpg
 

beldar boathead

Well-Known Member
It is also important how your block is mounted. If your block is mounted like the first picture, and you are pulling down into the cockpit, then only a small surface area of the line will actually be contacting the block. Whereas if you have a combo or system where the cleat is up higher, it will allow more line to contact (thus better grip) I wish i had realized this before mounting, but still works pretty good.




View attachment 26069View attachment 26070
What Gregory said isn’t really applicable. When the sheet is cleated it doesn’t matter how much sheet is wrapped around the block as the cleat is “holding” the sheet, not you.

The block should be mounted lower so when YOU are holding the sheet more of it is wrapped around the block providing more friction.

That cleat on the cockpit lip in pic 2 is a pretty good idea since in most cases under sail you generally don’t want to cleat the sheet. The spot in pic 2 I think is meant for just momentary cleating.
 
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LaLi

Well-Known Member
I don't know what the 10:1 or 20:1 means in this case, might just be marketing. Ratios only make sense to me in the context of a pulley system, not a single block.
I've always understood those to mean that the line isn't supposed to move until the ratio between the pulling side and the holding side exceeds the given value. That is, you'd need a force equivalent to only 1 kg to hold against 20 kg worth of tension on the other side of a "20:1" block. Obviously this can't be very accurate as it has to vary quite a bit with line thickness and quality.

It is also important how your block is mounted.
In this example it actually isn't. When a line is cleated, it's irrelevant how much "grip" there is somewhere else in the system. The purpose of a ratchet block is to help with the holding and releasing of an uncleated line. (More or less what beldar just said.)

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tag

my2fish
I believe that the holding ratio (10:1, 15:1, 20:1, whatever it may be...) is the maximum based on the most contact of the sheet with the sheave (180-degrees per the image below), so in most practical cases on a Sunfish, you'd be hiking out with the sail close hauled or on some reach, and that angle would be less than 180-degrees, so you're holding ratio would be somewhat less than advertised.


that being said, I've been using a Harken 2135 for several years now, and love it. it does have the grooved sheave, and the standard 10:1 ratio, but it is a carbo ratchet (on/off switch), not the auto-load sensing version. this is a picture of my setup on the Minifish for my boys (I did use the cheaper Nautos block there).

mainsheet cleat parts list.png
 

L&VW

Well-Known Member
Aha!

It may be that my every-day Sunfish has the simpler carbo-ratchet Harken? And that the Delrin ball bearing repair kit (above) goes into the auto-load-sensing version? :oops:

I could check for a model number, but it's dark outside now. My Harken does have the little lever, and sounds like it's ratcheting.

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LaLi

Well-Known Member
L & VW, the picture you posted is of Torlon bearings, which I understand are for high-load big-boat blocks. No difference between automatic and manual (dinghy-size) ratchets, both use Delrin balls.
 
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