running backstays, blocks

[Fritz Koschmann]

My rigging plans call for running backstays, 1/4" wire spliced to 1/2" braid. The design calls for 4" blocks to handle the wire. Blocks this size are $350.00 and up, I would need two. Are there cheaper blocks that will do the job? I could make blocks but I am not sure of meeting the strength requirements, but weight isn't an issue as the blocks are on deck and wouldn't be in the way. Another option might be all fiber running stays. These would be a small diameter high tech spliced to a larger diameter line for handling. I know the high tech lines require larger sheaves but perhaps not as large as those required for wire. Any thoughts?

[Fritz Koschmann]

My rigging plans call for running backstays, 1/4" wire spliced to 1/2" braid. The design calls for 4" blocks to handle the wire. Blocks this size are $350.00 and up, I would need two. Are there cheaper blocks that will do the job? I could make blocks but I am not sure of meeting the strength requirements, but weight isn't an issue as the blocks are on deck and wouldn't be in the way. Another option might be all fiber running stays. These would be a small diameter high tech spliced to a larger diameter line for handling. I know the high tech lines require larger sheaves but perhaps not as large as those required for wire. Any thoughts?

[Fritz Koschmann]

My rigging plans call for running backstays, 1/4" wire spliced to 1/2" braid. The design calls for 4" blocks to handle the wire. Blocks this size are $350.00 and up, I would need two. Are there cheaper blocks that will do the job? I could make blocks but I am not sure of meeting the strength requirements, but weight isn't an issue as the blocks are on deck and wouldn't be in the way. Another option might be all fiber running stays. These would be a small diameter high tech spliced to a larger diameter line for handling. I know the high tech lines require larger sheaves but perhaps not as large as those required for wire. Any thoughts?

[Dan McCosh]

Without knowing what the rig layout is, there are a bit too many questions here. The wire-to-rope setup is usually done so that when the runner is set up, the low-stretch wire takes the load. The wire is not all that flexible, hence the larger block sheave diameter. High-tech line could eliminate the splice and allow a smaller block diameter--but the line isn't as durable as the wire, and has to be replaced on a regular basis. The sheave pin diameter sets the working load for a block, hence making one strong enough wouldn't be all that difficult. Also, due to the nature of a backstay, a simple sheave sans roller bearings would probably work as well.

[Dan McCosh]

Without knowing what the rig layout is, there are a bit too many questions here. The wire-to-rope setup is usually done so that when the runner is set up, the low-stretch wire takes the load. The wire is not all that flexible, hence the larger block sheave diameter. High-tech line could eliminate the splice and allow a smaller block diameter--but the line isn't as durable as the wire, and has to be replaced on a regular basis. The sheave pin diameter sets the working load for a block, hence making one strong enough wouldn't be all that difficult. Also, due to the nature of a backstay, a simple sheave sans roller bearings would probably work as well.

[Dan McCosh]

Without knowing what the rig layout is, there are a bit too many questions here. The wire-to-rope setup is usually done so that when the runner is set up, the low-stretch wire takes the load. The wire is not all that flexible, hence the larger block sheave diameter. High-tech line could eliminate the splice and allow a smaller block diameter--but the line isn't as durable as the wire, and has to be replaced on a regular basis. The sheave pin diameter sets the working load for a block, hence making one strong enough wouldn't be all that difficult. Also, due to the nature of a backstay, a simple sheave sans roller bearings would probably work as well.

[Gary Bergman]

I have no clue what type or size of boat you are discussing, but the running backstays on my Herreshoff ketch, 34' on deck, has small diameter Vectran with the outer cover peeled off, and small diameter(around 1 or 1 1/4") blocks. Never a problem, even in a gale.

[Gary Bergman]

I have no clue what type or size of boat you are discussing, but the running backstays on my Herreshoff ketch, 34' on deck, has small diameter Vectran with the outer cover peeled off, and small diameter(around 1 or 1 1/4") blocks. Never a problem, even in a gale.

[Gary Bergman]

I have no clue what type or size of boat you are discussing, but the running backstays on my Herreshoff ketch, 34' on deck, has small diameter Vectran with the outer cover peeled off, and small diameter(around 1 or 1 1/4") blocks. Never a problem, even in a gale.

[Don Z.]

If we knew the rig size, we could calculate the load on the mast, and then the load on the runners, which would lead us to the block size...

[Don Z.]

If we knew the rig size, we could calculate the load on the mast, and then the load on the runners, which would lead us to the block size...

[Don Z.]

If we knew the rig size, we could calculate the load on the mast, and then the load on the runners, which would lead us to the block size...

[paladin]

I use similar size wire on my running backs....but I do not have synthetic line spliced to it. I use a 3 1/2 inch diameter deck mounted turning block directly to the hyfield lever.....you can buy the sheaves...or make them...and the required hardware. Mine are through bolted to the deck but originally were to be anchored to the base of a lifeline stanchion (on my boat rather heavy construction).

[paladin]

I use similar size wire on my running backs....but I do not have synthetic line spliced to it. I use a 3 1/2 inch diameter deck mounted turning block directly to the hyfield lever.....you can buy the sheaves...or make them...and the required hardware. Mine are through bolted to the deck but originally were to be anchored to the base of a lifeline stanchion (on my boat rather heavy construction).

[paladin]

I use similar size wire on my running backs....but I do not have synthetic line spliced to it. I use a 3 1/2 inch diameter deck mounted turning block directly to the hyfield lever.....you can buy the sheaves...or make them...and the required hardware. Mine are through bolted to the deck but originally were to be anchored to the base of a lifeline stanchion (on my boat rather heavy construction).

[Fritz Koschmann]

OK here it is. The boat is a 40' Bolger catamaran complete except for rigging. I hope to launch in a month or so.

The red line is the backstay. Sail area is 675 sq'.

http://sailglacierbay.homestead.com/backstay_op_598x600.jpg
http://sailglacierbay.homestead.com/DE_9_05_003websmall.jpg

[Fritz Koschmann]

OK here it is. The boat is a 40' Bolger catamaran complete except for rigging. I hope to launch in a month or so.

The red line is the backstay. Sail area is 675 sq'.

http://sailglacierbay.homestead.com/backstay_op_598x600.jpg
http://sailglacierbay.homestead.com/DE_9_05_003websmall.jpg

[Fritz Koschmann]

OK here it is. The boat is a 40' Bolger catamaran complete except for rigging. I hope to launch in a month or so.

The red line is the backstay. Sail area is 675 sq'.

http://sailglacierbay.homestead.com/backstay_op_598x600.jpg
http://sailglacierbay.homestead.com/DE_9_05_003websmall.jpg

[Dan McCosh]

That appears to be a kind of odd setup--as the full load appears to go to a winch with a single line. Usually, there is a tensioning tackle or hyfield lever. Anyway, the determining factor is going to be the splice on the line. On a cat that size, at times there are going to be very heavy loads. The high-tech line would be a superior solution, I would think. It shouldn't be difficult to fabricate an appropriate turning block.

[Dan McCosh]

That appears to be a kind of odd setup--as the full load appears to go to a winch with a single line. Usually, there is a tensioning tackle or hyfield lever. Anyway, the determining factor is going to be the splice on the line. On a cat that size, at times there are going to be very heavy loads. The high-tech line would be a superior solution, I would think. It shouldn't be difficult to fabricate an appropriate turning block.

[Dan McCosh]

That appears to be a kind of odd setup--as the full load appears to go to a winch with a single line. Usually, there is a tensioning tackle or hyfield lever. Anyway, the determining factor is going to be the splice on the line. On a cat that size, at times there are going to be very heavy loads. The high-tech line would be a superior solution, I would think. It shouldn't be difficult to fabricate an appropriate turning block.

[Don Z.]

OK, if I'm understanding your diagram correctly, there's about a 120 degree angle on the stay lead. That means you'll need a block there that can handle about 175% of the load generated by the system. 3500# might not be a bad guess.

[Don Z.]

OK, if I'm understanding your diagram correctly, there's about a 120 degree angle on the stay lead. That means you'll need a block there that can handle about 175% of the load generated by the system. 3500# might not be a bad guess.

[Don Z.]

OK, if I'm understanding your diagram correctly, there's about a 120 degree angle on the stay lead. That means you'll need a block there that can handle about 175% of the load generated by the system. 3500# might not be a bad guess.

[StevenBauer]

Do you know about these guys: http://garhauermarine.com/

Steven

[StevenBauer]

Do you know about these guys: http://garhauermarine.com/

Steven

[StevenBauer]

Do you know about these guys: http://garhauermarine.com/

Steven

[Hwyl]

You should be able to find blocks that can handle that kind of load used. There are some on ebay.

Wire running back stays are a temporary abberation, everyone uses high tech rope now.

[Hwyl]

You should be able to find blocks that can handle that kind of load used. There are some on ebay.

Wire running back stays are a temporary abberation, everyone uses high tech rope now.

[Hwyl]

You should be able to find blocks that can handle that kind of load used. There are some on ebay.

Wire running back stays are a temporary abberation, everyone uses high tech rope now.

[Ian McColgin]

Bolger has more fun than any man should have with cloths on. Though if you sail to the South Seas . . .

Anyway, running backs are not hugely stressed, as witness the very odd place to land a stay. I'd have brought it down to the hull and maybe along some fairleads past the windows.

It also seems pretty pricy to have wire blocks and winches and all.

On Goblin's 750 square foot main, the runners (which went to counter the mainstaysail stay) were 1/4" wire that went to a becket on a block that had a becket at each end. From the lower becket I spliced on ordinary dacron that ran to a block on deck, up through the hanging block and down to a second block on deck a little way off from the first, the better to spread the strain.

I made the wire length such that when cast off the wire could travel forward and lay smoothly against the shroud with the block just above the turnbuckle.

I had two shackles and a bit of bungee connecting the shroud to the runner that would slide up when the runner was set up and would fall down, pulling the runner forward to the shroud, when it was released.

The runners could be led to the sheet winches if someone was so slow at setting it up that the mast wanted to pump a lot. But really, that 3:1 was adequate with just a good arm on.

Anyway, different boats, different longsplices.

G'luck

[Ian McColgin]

Bolger has more fun than any man should have with cloths on. Though if you sail to the South Seas . . .

Anyway, running backs are not hugely stressed, as witness the very odd place to land a stay. I'd have brought it down to the hull and maybe along some fairleads past the windows.

It also seems pretty pricy to have wire blocks and winches and all.

On Goblin's 750 square foot main, the runners (which went to counter the mainstaysail stay) were 1/4" wire that went to a becket on a block that had a becket at each end. From the lower becket I spliced on ordinary dacron that ran to a block on deck, up through the hanging block and down to a second block on deck a little way off from the first, the better to spread the strain.

I made the wire length such that when cast off the wire could travel forward and lay smoothly against the shroud with the block just above the turnbuckle.

I had two shackles and a bit of bungee connecting the shroud to the runner that would slide up when the runner was set up and would fall down, pulling the runner forward to the shroud, when it was released.

The runners could be led to the sheet winches if someone was so slow at setting it up that the mast wanted to pump a lot. But really, that 3:1 was adequate with just a good arm on.

Anyway, different boats, different longsplices.

G'luck

[Ian McColgin]

Bolger has more fun than any man should have with cloths on. Though if you sail to the South Seas . . .

Anyway, running backs are not hugely stressed, as witness the very odd place to land a stay. I'd have brought it down to the hull and maybe along some fairleads past the windows.

It also seems pretty pricy to have wire blocks and winches and all.

On Goblin's 750 square foot main, the runners (which went to counter the mainstaysail stay) were 1/4" wire that went to a becket on a block that had a becket at each end. From the lower becket I spliced on ordinary dacron that ran to a block on deck, up through the hanging block and down to a second block on deck a little way off from the first, the better to spread the strain.

I made the wire length such that when cast off the wire could travel forward and lay smoothly against the shroud with the block just above the turnbuckle.

I had two shackles and a bit of bungee connecting the shroud to the runner that would slide up when the runner was set up and would fall down, pulling the runner forward to the shroud, when it was released.

The runners could be led to the sheet winches if someone was so slow at setting it up that the mast wanted to pump a lot. But really, that 3:1 was adequate with just a good arm on.

Anyway, different boats, different longsplices.

G'luck

[JimConlin]

It would be a good start to ask the designer what load he calculated for the backstays.

[JimConlin]

It would be a good start to ask the designer what load he calculated for the backstays.

[JimConlin]

It would be a good start to ask the designer what load he calculated for the backstays.

[John Gearing]

Yep, ask Phil Bolger. Also, only landlubbers use "rope". On a boat you use "lines".
;-)

[kc8pql]

Do you know about these guys: http://garhauermarine.com/
I'll second Garhauer. Very nice blocks, factory direct, for a fraction of the big boys. 4" 316 SS torlon ball bearing, safe working load 5000 lbs., $84.70.

[Thad Van Gilder]

IVY has wire runners, and they go to a pair of galvanized industrial wire blocks.

-Thad