Replacing mainsheet blocks: plain or ball bearings ?

[Pirx]

We have to replace the mainsheet fiddle blocks on our Moody 31. Barton size 5 blocks look suitable, they are available with either plain or ball bearings and there is not a huge price difference between them. Mainsail area is not huge: 18m2 and we are happy with a 4-part sheet and 12mm line.
Any thoughts ? Should we be looking at anything else ?

 

[LiftyK]

I have Barton blocks on my coach roof-mounted main sheet blocks on a 27’ yacht. Changing from plain to ball bearings made a very positive difference. The sail now runs out freely even in light winds. Recommended.

 

[Daydream believer]

I have 4;1 in a 28M2 mainsail using barton ball race blocks. The mainsheet runs on a cockpit traveller. In the past it has not worried me that it has only been 4:1. However, now I am older, I begin to find fine tuning up wind harder, so I considered 6:1. But this would leave me with lots of sheet to deal with. Being SH it can be awkward gybing etc.
In the end I installed a much lighter 4:1 tackle to the tail of the mainsheet long enough to reach the boom when nearly close hauled. I have a much smaller set of blocks ( actually it is an old kicking strap set up)This makes trimming very easy.
The point of this is that by doing this one would not need ball bearing blocks on the mainsheet, as for general boom positioning it is fairly easy. ( but still nice to have) But once the weight gets heavier- ie upwind- one effectively reverts to 16:1
I have a 10mm mainsheet & find it perfectly OK. 12 mm would create far too much friction- in my view
So you may consider this when you do the re rigging, if like many of us , you have the spare fittings, collected over the years.

 

[dunedin]

Plain bearings tend to have higher safe working load than blocks with roller or ball bearings. Rarely a major issue though.
However, one potential issue with ball bearings is going flat when held under a lot of tension in the same place for a long time - not an issue when sailing, but more so when left under tension when not sailing. Also tends to affect roller bearing mainsheet traveller cars.

 

[Daydream believer]

However, one potential issue with ball bearings is going flat when held under a lot of tension in the same place for a long time - not an issue when sailing, but more so when left under tension when not sailing. Also tends to affect roller bearing mainsheet traveller cars.

The only places I would expect such a situation (on my boat at least) would be the reefing blocks on the sail luff ( I have single line reefing) , particularly first reef. This, to date after 18 years, has not proved an issue. The other is the sheet to the self tacking jib. The clew has a bearing block arrangement to give 2:1 & gets a lot of load upwind. I have had this for 6-8 years (not sure exactly)& the system is developing some friction, so now you have mentioned it I will check.
In any event, I do not think that provided the blocks are within the designed loading it should be a problem.
There is a difference between direct 180 degree pull & say 45 degree that one gets on something like a genoa car . As a result it is easy to use a block that is overloaded without studying the data sheet when buying

 

[LONG_KEELER]

I went for roller bearings on genoa track blocks one time.

Great in light winds tacking with a 100% plus jib. They were too good otherwise and seemed to get caught on things. I went back to my old blocks that had a nice bit of drag.

I think they would work much better on a mainsheet tackle where you have close control without winching and plenty of friction
.

 

[Poey50]

I found that 4:1 when hard-pressed upwind was not enough on our 32 footer and the cam cleat was also slipping so decided to go 6:1 with 60 mm sheaves and ball bearings rather than 50mm sheaves plain bearing - which was my original thought - and also drop down from 12 mm to 10 mm diameter sheet as 6:1 is a lot more friction even with the ball bearings.

 

[PetiteFleur]

I fitted Barton ball bearing blocks on my Moody 33 a couple of years after buying - made a big difference, much easier to pull in, not sure of the size, probably no 5, and a new mainsheet which is 14mm but easier holding and pulling.

 

[Wing Mark]

My 28ft boat is going to get a 3inch Harken ball bearing ratchet block on the main.
Because I have one in the drawer, bought for a Laser.

Very often a lot of the friction is in the rope, the act of bending a stiff, loaded rope around a small sheave is a lot of work.
Bigger sheave or smaller rope, or better rope can help a lot.

Remember the load on the sheet will also vary depending on how you use the kicker and the traveller. If the boom isn't strong enough for the kicker to do the hard work of leach tension, then the sheet is loaded much
more.

 

[arc1]

I went 6:1 with 10mm sheet on our Moody 31, so that our 10 year old could better use main sheet. Downside is amount of rope in cockpit, although worth it for us (also means I've been able to sheet in fairly comfortably, in a lot stronger winds than I could before) Went plain bearings but have to give the boom a helping hand to pay out when wind abaft beam and light - not a huge issue but sometimes wish I'd stumped up for ball bearings.

 

[Pirx]

Thank you everyone, that's all interesting and very helpful. We managed ok with the rattly, worn out, obsolete Lewmar 4:1 plain bearings, so I think we'll have 4:1 with balls (!) this time. The 12mm rope is ok for another season or two so we'll keep that for the time being.

 

[dunedin]

Thank you everyone, that's all interesting and very helpful. We managed ok with the rattly, worn out, obsolete Lewmar 4:1 plain bearings, so I think we'll have 4:1 with balls (!) this time. The 12mm rope is ok for another season or two so we'll keep that for the time being.

The rope is often a large part of the issue. A wash in fabric conditioner can help.

 

[Pirx]

It's in the machine as I type .................... !

 

[[70521]]

I fitted Barton ball bearing blocks on my Moody 33 a couple of years after buying - made a big difference, much easier to pull in, not sure of the size, probably no 5, and a new mainsheet which is 14mm but easier holding and pulling.

I had a chat with the chap on the Barton stand at the Southampton Boat Show asking why they did not put the size on their products and how useful it would be. I was told that you need to measure the width of the block to work out the size!

I shall be replacing my Barton blocks with another make that clearly displays their size/part number in future.

 

[dunedin]

I had a chat with the chap on the Barton stand at the Southampton Boat Show asking why they did not put the size on their products and how useful it would be. I was told that you need to measure the width of the block to work out the size!

I shall be replacing my Barton blocks with another make that clearly displays their size/part number in future.

That might limit your choices a bit. Perhaps we should have forum whip round to buy you a small tape measure
Indeed most people can judge the pulley size by eye

 

[Alfie168]

That might limit your choices a bit. Perhaps we should have forum whip round to buy you a small tape measure
Indeed most people can judge the pulley size by eye

It would still be useful to have things marked. I'd say that most people will make mistakes if the opportunity is placed in front of them. It's not that big an ask.
I have recently had great "fun" with unmarked trailer axle parts getting replacements. Even the local agent was not impressed that wheel stud holes had been drilled through the part number cast into the drums, so we had to make an educated guess as to whether they were imperial or metric bearings...both being available for the drum size. It should have been so easy.

 

[[70521]]

That might limit your choices a bit. Perhaps we should have forum whip round to buy you a small tape measure
Indeed most people can judge the pulley size by eye

There are a number of competitors in the marketplace. I have several tape measures, a vernier caliper and my late father's micrometer, but that is an imperial instrument and only kept for sentimental reasons.

I much prefer to be able to give a part number to the online ordering system, or the nice person at the local mainsheet block shop. With 40 years in engineering I can't understand why Barton fail to do something as simple as put a part number on the component, the rest of the planet does.