Single line reefing sheave blocks

[Desmo]

Just taken my main sail off my Beneteau 323 for the first time and noticed the 4 sheave blocks fixed onto the sail (only 2 reefs) has 2 differing types of wheel. The pic shows a smaller alloy one at 36mm diameter whilst the other is nylon 60mm diameter item. All 4 block housings are the same and the sail is the original Beneteau item. All 4 sheaves were secured with a 6mm domed head screws with a thin nut of with a differing thread form and jammed on! Clearly a bodge job. The sail is in good nick and I plan to replace all 4 but would like to know:
1. Which of these were the original if either?
2. Would replacing with ball bearing versions be beneficial?

 

[ithet]

The one on the left look the same as on my Beneteau, although I would have to check in the loft for the original French sail to be sure.
Do not think a ball bearing sheave would achieve much, but I reduced the line to 8mm which made a big difference (on a 331).

 

[Neeves]

You don't make it clear why you are replacing the sheaves, at all. They might be different sizes, the attachment might be a bodge (but you can remedy the bodge with correct nut) has nothing to do with the sheaves.

If the sheaves allow you to reef 'easily' why change the sheaves?

Ball bearing blocks will undoubtedly be better, but you might not notice the difference . I'm with ithet - if you have issues - change the reefing lines to something smaller.

We worked out where we handled the line, at the clutch and on the winch, we spliced thinner, dyneema, beyond the hand operated part of the line - its all much easier. But with simple sheaves, as you have, may allow the reefing lines to 'fall off' the sheaves (how are the lines retained on the sheaves?) Replacing with ball bearing blocks might give you more certainty.

Tell us more - we cannot guess.

Jonathan

 

[jwilson]

I imagine your sail is an original Elvstrom as often supplied with Beneteaus and Jeanneaus. Mine had cheeks for the block sewn into the sail, with alloy sheaves that looked much like yours - often they were far from free-running, and occasionally seized completely. When I had a new mainsail made I had external blocks attached to the eyes in the sail with a ring and short webbing strap. Also a third set of reefing eyes, though you have to choose to put the 2nd reef blocks in there to use them.

Early and late in the year I often leave reefs 2 and 3 set up for use, in midsummer only 1 and 2. With a modern boat that does not like heeling much you quite often needed a deeper reef than he original "factory" Elvstrom sail gave me.

 

[Desmo]

The one on the left look the same as on my Beneteau, although I would have to check in the loft for the original French sail to be sure.
Do not think a ball bearing sheave would achieve much, but I reduced the line to 8mm which made a big difference (on a 331).

Thanks. reducing to 8mm sounds a good shout.

@jwilson: Yes its an Elvstrom. One of the small alloy sheave had seized completely.

@Neeves: Looking to replace all 4 as they are not expensive and at present I cant find a direct copy of the larger nylon one on the left. The alloy ones had sized up and corroded onto the alloy housings.

 

[thinwater]

Load rating can be a problem with small ball bearing sheaves, and the reef clews must take the full mainsheet load, hard on the wind and during an uncontrolled jibe. I'd stay with a bushing. better to stay light and simple.

 

[Neeves]

Thanks. reducing to 8mm sounds a good shout.

@jwilson: Yes its an Elvstrom. One of the small alloy sheave had seized completely.

@Neeves: Looking to replace all 4 as they are not expensive and at present I cant find a direct copy of the larger nylon one on the left. The alloy ones had sized up and corroded onto the alloy housings.

I went down to 6mm and spliced on 10mm for the part you actually handle. When our sail was built I had a 3 rd reef installed, normally only 2. We use the third reef a lot, more than the 1st. The 3rd reef reduces the sail by 75%. Its a lot of string - hence the 6mm (in dyneema) - as above ball bearing blocks attached by tape to the sail through the reefing eyes. We normally reef a bit late and put the second reef in, hence not using the first reef much. When we take the 2nd reef in we also collect all the loose line for the 3rd reef or there is string everywhere. There is no load when taking this loose string in so handling 6mm line is not an issue. Having such a small sail with the 3rd reef in means I did not have a trysail built - as I could not imagine installing one, short handed, when the conditions dictated it was needed.

We know it all works as we were caught on a reach in an unforecast local storm crossing Bass Strait with 8 hrs of gusting to 55 knots and were comfortable with only the 3 reefed main - though seas were breaking over the cabin roof. The boat handled it well - the crew, 2 of us, a bit apprehensive.

It seems you are rightly considering your options and being forced to make some changes - I'd seriously consider a 3rd reef and off the shelf blocks (rather than the simple sheaves). You could replace all the lines with dyneema - and you can go down at least one size - as this will make reefing easier, less friction by virtue of the thinner line. You can use the old reefing lines as replacement sheets, outhaul, Cunningham etc.

Jonathan