I recently posted a question concerning the proper way to attach a cheek block to the top of my C22 Sport in order to turn the main halyard aft. I got some great answers and now have another question. The halyard will turn aft at the cheek block and then through either a rope clutch or cam cleat. The specs for the Harken Big Bullet Cheek Block lists a 300 pound working load with a 2000 pound breaking strength. Will the 300 pound working load be sufficient for the main halyard. I have no idea what the load is on the halyard, but I would think it would be considerably less that 300 pounds, even with the sail under load. Am I correct, or do I need to go back to the drawing board? Chuck Turner
Cheek block working load
- Thread starter Chuck Turner3968
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Ross, don't you mean
NO, he does not weigh 300 lbs. (or more), and YES, he can hoist the sail by hand? That combination would mean that there is less than 300 lbs. tension on the halyard.
NO, he does not weigh 300 lbs. (or more), and YES, he can hoist the sail by hand? That combination would mean that there is less than 300 lbs. tension on the halyard.
Does not the wind loading on the main...
Have an affect on the total working load? This I have often wondered. And is not the load really applied to the mastbase block? I would think that the cheekblock would have minimal stress on the lateral bias.
Have an affect on the total working load? This I have often wondered. And is not the load really applied to the mastbase block? I would think that the cheekblock would have minimal stress on the lateral bias.
Chuck...
your big bullet cheek block is fine. Takes up to 3/8" line... more than enough on a C22. Though it's a bit pricier, you might consider installing a Harken small boat organizer.. double or triple... rather than the cheek, in case you want to run another line aft, such as a cunningham, jib halyard, vang. etc.
your big bullet cheek block is fine. Takes up to 3/8" line... more than enough on a C22. Though it's a bit pricier, you might consider installing a Harken small boat organizer.. double or triple... rather than the cheek, in case you want to run another line aft, such as a cunningham, jib halyard, vang. etc.
We've got everything you need here.....
http://shop.catalinaowners.com/c22/detail-modspec.htm?fno=20&gid=76 OOps, got truncated somehow. As I was saying, I really like the Spinlock clutches, but they are a bit of an expense when the the Spinlock PXR cam cleats are more than adequate for the job. Dave Groshong Customer Service SailboatOwners.com
http://shop.catalinaowners.com/c22/detail-modspec.htm?fno=20&gid=76 OOps, got truncated somehow. As I was saying, I really like the Spinlock clutches, but they are a bit of an expense when the the Spinlock PXR cam cleats are more than adequate for the job. Dave Groshong Customer Service SailboatOwners.com
You need to do some homework.
Here is a link to a site that will give you all your answers. I'm sure that you plan to take your mainsail halyard down to a block at the mast step, then go across to your cheek block, and then back through a clutch (NOT A CAM CLEAT!!!). Study the layouts on this site for safety and success.http://www.westmarine.com/webapp/wcs/stores/servlet/westadvisor/10001/-1/10001/Blocks-SafeWorkingLoad.htm
Here is a link to a site that will give you all your answers. I'm sure that you plan to take your mainsail halyard down to a block at the mast step, then go across to your cheek block, and then back through a clutch (NOT A CAM CLEAT!!!). Study the layouts on this site for safety and success.http://www.westmarine.com/webapp/wcs/stores/servlet/westadvisor/10001/-1/10001/Blocks-SafeWorkingLoad.htm
Didn't mean to offend you Jimq
I'm glad you're passionate about the clutches, they are superior, but the Spinlock PXR's are up to the task, believe me through experience, not homework. http://www.spinlock.co.uk/sitev2/default.cfm?section=1010&productarea=cleats&entrynum=12
I'm glad you're passionate about the clutches, they are superior, but the Spinlock PXR's are up to the task, believe me through experience, not homework. http://www.spinlock.co.uk/sitev2/default.cfm?section=1010&productarea=cleats&entrynum=12
Hey - QM1 - nothing offends me!! (chuckle)
My experience has always been with Spinlock rope clutches, but as you point out - a lot of people are happy with the Spinlock PXR units. You make good sense for this particular application. I think you will agree about not taking the halyard straight down to a cheek block. You should have a block on the mast step to assist with the purchase and eliminate line chafe. (I know - read your link - that says it all)
My experience has always been with Spinlock rope clutches, but as you point out - a lot of people are happy with the Spinlock PXR units. You make good sense for this particular application. I think you will agree about not taking the halyard straight down to a cheek block. You should have a block on the mast step to assist with the purchase and eliminate line chafe. (I know - read your link - that says it all)
Yep, Jimq
It must be lead to a cheek or deck organizer through a spring loaded stand up, otherwise as you well know you end up with a tortured lead! dave
It must be lead to a cheek or deck organizer through a spring loaded stand up, otherwise as you well know you end up with a tortured lead! dave
At the base of the mast there is an option
to use a stand-up block OR an upright lead block. The standup block is as described, a regular block on a base with a spring to keep it from flopping down when not under load. The upright lead block simply turns the line 90 degrees, and could be considered another option. We used the upright leads on our C22 when we did this project. Upright lead blocks are called mastbase lead blocks by Harken. Please note that West Marine's catalogs do not show all the blocks made by individual manufacturers. To simplify the discussion, in general with "regular" line (i.e., NOT high tech) the size of the block that matches or slightly exceeds the size of the line means that the block will be adequate, structurally. I would caution against using cam cleats for halyards. It's just not a proper application of the device for that use. Either a simple cleat or a sheet stopper should be used. For a C22 main halyard, a cleat on the cabintop would be just fine.
to use a stand-up block OR an upright lead block. The standup block is as described, a regular block on a base with a spring to keep it from flopping down when not under load. The upright lead block simply turns the line 90 degrees, and could be considered another option. We used the upright leads on our C22 when we did this project. Upright lead blocks are called mastbase lead blocks by Harken. Please note that West Marine's catalogs do not show all the blocks made by individual manufacturers. To simplify the discussion, in general with "regular" line (i.e., NOT high tech) the size of the block that matches or slightly exceeds the size of the line means that the block will be adequate, structurally. I would caution against using cam cleats for halyards. It's just not a proper application of the device for that use. Either a simple cleat or a sheet stopper should be used. For a C22 main halyard, a cleat on the cabintop would be just fine.
Don't get too hung up on the term cam Stu.....
The Spinlock PXR cam I refer to is more of a rope clutch than it is a simple cam, we are talking about a Catalina 22, not a 30. Check out the picture: http://shop.sailboatowners.com/category.htm?fno=400&cat=1910 Dave Groshong
The Spinlock PXR cam I refer to is more of a rope clutch than it is a simple cam, we are talking about a Catalina 22, not a 30. Check out the picture: http://shop.sailboatowners.com/category.htm?fno=400&cat=1910 Dave Groshong
Stand up block
I'm sure you all know that the main halyard on the C22 Sport is internl and exits the mast through a sheave about six inches from the base of the mast. Dane Condon at American Sail said that I would not need the stand up block. He indicated that the halyard would have a fairlead to the cheek block right out of the mast. (Incidentally, the reason I am using the cheek block and not a deck organizer is that I do not have much of a surface to mount to and it is not flat). Anyway, do you think I need the standup block. Chuck
I'm sure you all know that the main halyard on the C22 Sport is internl and exits the mast through a sheave about six inches from the base of the mast. Dane Condon at American Sail said that I would not need the stand up block. He indicated that the halyard would have a fairlead to the cheek block right out of the mast. (Incidentally, the reason I am using the cheek block and not a deck organizer is that I do not have much of a surface to mount to and it is not flat). Anyway, do you think I need the standup block. Chuck
Chuck, You need to place the cheek block where
you think you want it and check the lead to be sure the line doesn't bear on either cheek. You may need a wedge under the block so that the entry is fair. If as you say the exit from the mast is 6 inches above the deck, the lead to the cheek block will be angled and from there the lead to the cockpit will be close to the deck. Perhaps the block should be mounted so that the plane of the fasteners is the same as the angle of the plane of the line when it exits the mast.
you think you want it and check the lead to be sure the line doesn't bear on either cheek. You may need a wedge under the block so that the entry is fair. If as you say the exit from the mast is 6 inches above the deck, the lead to the cheek block will be angled and from there the lead to the cockpit will be close to the deck. Perhaps the block should be mounted so that the plane of the fasteners is the same as the angle of the plane of the line when it exits the mast.
So what is the answer?
The very first response was the only attempt at an answer. But it is incomplete because the sail will add to the load. Probably minimally but I would still like to know the actual working load. And the more money you spend to reduce friction the more load exists at the clutch. I too know from experience on my H37C that almost any cheek block/organizer/clutch combination will handle a halyard. Still want to know how to calculate the real number!
The very first response was the only attempt at an answer. But it is incomplete because the sail will add to the load. Probably minimally but I would still like to know the actual working load. And the more money you spend to reduce friction the more load exists at the clutch. I too know from experience on my H37C that almost any cheek block/organizer/clutch combination will handle a halyard. Still want to know how to calculate the real number!
Ed the friction works against you when you
are pulling the rope but it works for you when you hold the rope static. Each block will add friction and as such will act as a brake to hold the strain. The sail is supported on the mast by the slides or what ever means is used to keep the sail close to the mast. Therefore the wind load on the sail trying to pull the luff out of straight will be divided between the slides and reduced by friction. On my boat the boom is free to move up on a short track and when I hoist the sail I lift the boom off the stop at the bottom and off the boom gallows. I do have a down haul on the boom but don't often use it. The boom never lifts on the track while we are sailing. The boom weighs about 45 pounds. Having said all of that I don't think that the wind has much effect on the halyard tension. I use a small winch to hoist my sail the last couple of feet. The drum is about 2 1/2 inches in diameter and the winch handle is ten inches long. Thus the mechanical advantage with the winch is 10/1.25= 8 .So if I apply 30 pounds force on the winch handle that translates to 240 pounds force on the halyard. I leave those turns on the winch and cleat the tail. Now at the top of the mast the sheave has to support the load of the sail and the load of the halyard. So the load on the sheave is the sum of the two loads or 480 pounds. Does that help?
are pulling the rope but it works for you when you hold the rope static. Each block will add friction and as such will act as a brake to hold the strain. The sail is supported on the mast by the slides or what ever means is used to keep the sail close to the mast. Therefore the wind load on the sail trying to pull the luff out of straight will be divided between the slides and reduced by friction. On my boat the boom is free to move up on a short track and when I hoist the sail I lift the boom off the stop at the bottom and off the boom gallows. I do have a down haul on the boom but don't often use it. The boom never lifts on the track while we are sailing. The boom weighs about 45 pounds. Having said all of that I don't think that the wind has much effect on the halyard tension. I use a small winch to hoist my sail the last couple of feet. The drum is about 2 1/2 inches in diameter and the winch handle is ten inches long. Thus the mechanical advantage with the winch is 10/1.25= 8 .So if I apply 30 pounds force on the winch handle that translates to 240 pounds force on the halyard. I leave those turns on the winch and cleat the tail. Now at the top of the mast the sheave has to support the load of the sail and the load of the halyard. So the load on the sheave is the sum of the two loads or 480 pounds. Does that help?
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