Is there an economoical alternative to Ronstan/Harken/Lewmar sheave blocks?

[Kukri]

I have a “personal rule” that I never let a good second hand Harken block, winch handle, etc. which is for sale on eBay at a low price go past me.

 

[Wing Mark]

I have a “personal rule” that I never let a good second hand Harken block, winch handle, etc. which is for sale on eBay at a low price go past me.

I think you missed a couple last week ;-)

 

[Kukri]

I think you missed a couple last week ;-)

Well done! Although I am now slowing down a bit.

Oddly enough the bigger boat sizes are not so much in demand, and blocks for a fifty footer can be cheaper than the next size down!

 

[Wing Mark]

When I think about the idea of people making their own blocks, I am imagining the threads a few years later explaining how they had a failure at the most unfortunate moment that meant the boat couldn't be used/put lives in danger/caused damage (delete as appropriate).

15mm dia implies high loads, it's up the OP but I can't see that messing around trying to handcraft something for these loads on this application is a worthy cause.

FWIW when I needed to change the mainsheet blocks on our previous boat (16mm line) I downsized the line to dyneema and bought cheaper blocks. The line was re-purposed as a dockline which we needed anyway so it wasn't a waste.

I've not made blocks for high loads, but fundamentally, they are simple things to make strong.
Two stainless straps with two holes, one for the sheave axles and one for the shackle is not rocket science.
Two bolts in shear is a standard thing you can look up.
Making them rotate smoothly perhaps takes a little more thought....

 

[greeny]

I have a “personal rule” that I never let a good second hand Harken block, winch handle, etc. which is for sale on eBay at a low price go past me.

So its you that keeps outbidding me.

 

[PetiteFleur]

Barton Marine Equipment Ltd. Excellent range and cheaper than the mentioned. I use their ball bearing blocks on my mainsheet and it made it so easy. The boom strut is good as well - using the KISS principle...

 

[Wing Mark]

Barton Marine Equipment Ltd. Excellent range and cheaper than the mentioned. I use their ball bearing blocks on my mainsheet and it made it so easy. The boom strut is good as well - using the KISS principle...

Indeed, once you go above the SWL of dinghy stuff, Barton have a lot to offer.
Just bought a (new) block with SWL over 300kg for under £12.
Their plain bearing blocks are quite low friction too.

People seem to want a lot of cash for second hand fittings these days.

 

[coopec]

As wing mark says, the diagram and the photo have very different setups. And neither of which looks ideal to me.
And the optimum system will depend on whether cockpit/transom mounted, like the diagram, or ahead of the cockpit, like the photograph.[/COLOR]

Need to design the sheeting system fully before investing in expensive pulleys. We have a track ahead of the hatch, with mainsheet led back to helm, using all Ronstan blocks, which is ideal for us - but not the cheapest.

Then once designed and satisfied (possibly using a mock-up with thin rope and dinghy pulleys), be prepared to invest in quality blocks for this application. The forces after a strong wind gybe can be fearsome, particularly if somebody lets happen by accident. If the mainsheet blocks fail you could seriously injure (or worse) crew members, break the boom or even take the mast out.
Clearly we all use gybe preventers and try to prevent accidental gybes. But if you do the miles it will happen eventually.

Dunedin

Thanks for your comment but at this stage I'm just getting ideas : thinking ahead (as one must do when building a yacht)!

Of course I wouldn't do anything without running it past the people who are going to rig the yacht and design the system. But if they supply the gear I know I will be paying full retail price for Harken, Lewmar or Ronstan and I don't want that.

I am thankful for the excellent suggestions from various people commenting.
AND AngusMcDoon / PetiteFleur I will certainly look at Barton

 

[coopec]

Apparently the "Block and Tackle" system is fairly common.

Refitting traveler and tackle - Cruisers & Sailing Forums

 

[dunedin]

Apparently the "Block and Tackle" system is fairly common.

Refitting traveler and tackle - Cruisers & Sailing Forums

Well not according to the text “the first and only time seen this arrangement”, sounds fairly uncommon.
And if you look carefully, I think that in the first post is twin entirely separate mainsheets - so that would immediately double the cost for your blocks and ropes. Clearly it worked for him - as a solo round the world racer, with no crew in the cockpit and tacking or gybing happening every few days, rather than every few minutes tacking up a narrow channel.
But otherwise it seems like a lot of extra problems, and more seriously with the extra loops of mainsheet, a severe safety risk to crew in the cockpit.
I would suggest if not done so you first determine whether your mainsheet will go across the cockpit or ahead of the sprayhood. The forward position is safer for a cruising boat (sadly impacts by mainsheet in gybe is one of the most common causes of fatalities), but puts more strain on the mainsheet - and only works if sprayhood starts behind at least 50% of the mainsail foot length. If sheet needs to be across or behind the cockpit, designing to minimise the risk to the crew would be my next priority.

 

[anoccasionalyachtsman]

Well not according to the text “the first and only time seen this arrangement”, sounds fairly uncommon.
And if you look carefully, I think that in the first post is twin entirely separate mainsheets - so that would immediately double the cost for your blocks and ropes. Clearly it worked for him - as a solo round the world racer, with no crew in the cockpit and tacking or gybing happening every few days, rather than every few minutes tacking up a narrow channel.
But otherwise it seems like a lot of extra problems, and more seriously with the extra loops of mainsheet, a severe safety risk to crew in the cockpit.
I would suggest if not done so you first determine whether your mainsheet will go across the cockpit or ahead of the sprayhood. The forward position is safer for a cruising boat (sadly impacts by mainsheet in gybe is one of the most common causes of fatalities), but puts more strain on the mainsheet - and only works if sprayhood starts behind at least 50% of the mainsail foot length. If sheet needs to be across or behind the cockpit, designing to minimise the risk to the crew would be my next priority.

I mentioned it in #19. It was fitted to a production boat, of which around 200 were built, and their owners liked it. If it's up on the coachroof then there's no problem with second loops, and whilst not having the least possible blocks, it's much the same as most.

 

[coopec]

I mentioned it in #19. It was fitted to a production boat, of which around 200 were built, and their owners liked it. If it's up on the coachroof then there's no problem with second loops, and whilst not having the least possible blocks, it's much the same as most.

You are not wrong!

 

[Wing Mark]

I mentioned it in #19. It was fitted to a production boat, of which around 200 were built, and their owners liked it. If it's up on the coachroof then there's no problem with second loops, and whilst not having the least possible blocks, it's much the same as most.

For many boats, putting the mainsheet up on the coach roof out of the way means it is near the middle of the boom, requiring a greater number of blocks, or bigger blocks and bigger winch. It also demands that the boom is quite strong, although that may be the case anyway if the kicker is powerful.

 

[anoccasionalyachtsman]

For many boats, putting the mainsheet up on the coach roof out of the way means it is near the middle of the boom, requiring a greater number of blocks, or bigger blocks and bigger winch. It also demands that the boom is quite strong, although that may be the case anyway if the kicker is powerful.

I'm not sure what that has to do with single or twin mainsheets?

 

[dunedin]

I mentioned it in #19. It was fitted to a production boat, of which around 200 were built, and their owners liked it. If it's up on the coachroof then there's no problem with second loops, and whilst not having the least possible blocks, it's much the same as most.

The double mainsheet system on the round the world Rustler has exactly double the number of blocks otherwise needed. The A shaped version in the OP’s original post diagram avoids this waste, and avoids the hassle of having to adjust two separate main sheets - so would be better in every way except pulling boom to centreline for a light wind beat.

 

[anoccasionalyachtsman]

The double mainsheet system on the round the world Rustler has exactly double the number of blocks otherwise needed. The A shaped version in the OP’s original post diagram avoids this waste, and avoids the hassle of having to adjust two separate main sheets - so would be better in every way except pulling boom to centreline for a light wind beat.

Look, I'm not advocating that the double system is in any way perfect, but that's not a word often associated with coachroof mounted systems anyway! And you're right about that Rustler (which has also avoided the cost of a traveller etc.), but a lot of the coachroof systems not only have the two main blocks, and often lead the sheet out to both sides of the cockpit, or along the boom and back. Then you might also have traveller lines and the sheaves that they use. It's those more complex setups that I include when I say 'most'. And the double system can give as good a range of control as a modest traveller - if you can be bothered with adjusting both - the 'A' system can't.

 

[Wing Mark]

The double mainsheet system on the round the world Rustler has exactly double the number of blocks otherwise needed. The A shaped version in the OP’s original post diagram avoids this waste, and avoids the hassle of having to adjust two separate main sheets - so would be better in every way except pulling boom to centreline for a light wind beat.

Which do you mean by 'A shaped'?
The system in the photo is very versatile, if you notice the adjustable nature of the blue lines.

If people want to centre the main for a light wind beat, it's not hard to add a temporary line to achieve that.
We accept this sort of thing for jibs, two sheets, barber haulers, sheet to a different track for a reach etc.

 

[fredrussell]

…The system in the photo is very versatile, if you notice the adjustable nature of the blue lines.

They’re just tied off in that pic, no? To adjust them looks like a right faff to me.

 

[anoccasionalyachtsman]

They’re just tied off in that pic, no? To adjust them looks like a right faff to me.

If you scroll down here you'll see that its creator calls it temporary. It seems that Jeanneau have been offering a version.

 

[Wing Mark]

They’re just tied off in that pic, no? To adjust them looks like a right faff to me.

Many dinghies use something a bit similar, the strop is adjusted by sliding the splices in a dyneema bridle.
Only adjusted between races..
The image is clearly a roller-reef main, where the mast stays straignt and the boom stays at 90 degrees to it (pretty much!).
Not a boat where you will be tweaking the kicker much?
As soon as the boom leaves the centreline, the kicker is doing nearly all the leach tension.
Needs a strong boom.