When reefing on my 1998 H376 (single line reef), the tack of the sail pulls tight, but the clew does not. Causing the sail to be baggy, not flat. I hate to keep cranking the reefing line in. The tack has a block that the line goes thru before the line goes back thru the boom to the clew. Any suggestions?? Thanks. Bob
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Rich
Have another look at the diagram I posted. It is a diagram of the single line reefing system. The floating block inside the boom is part of that reefing system(not the outhaul) and it has a high failure probability. Adding ball bearing blocks at any point where a line makes a turn will help to reduce friction.
Have another look at the diagram I posted. It is a diagram of the single line reefing system. The floating block inside the boom is part of that reefing system(not the outhaul) and it has a high failure probability. Adding ball bearing blocks at any point where a line makes a turn will help to reduce friction.
Alan, take another look
I agree that the reefing lines are shown, but the internal block system is for the outhaul. If it were for the reefing, then you would need to pull a lot more on the reefing line and each foot of reefing line pull would result in much less reefing line being taken up at the clew. This is not the case. Also, there would have to be two block systems in the boom and there is not room for that. OTOH, pulling on the outhaul clearly indicates that the block system is used. This allows you to pull the foot very tight. If your rigging is not like I have described, then you have something quite different than my Z-Spar rig. I think the drawing is a bit misleading. Does your outhaul line route to the cockpit? Mine terminates on the boom. Also at the bottom of the drawing are variations of the outhaul connection to the sail which leads me to think that this drawing pertains to the outhaul and not the reefing lines. I think the reefing lines are only shown for perspective.
I agree that the reefing lines are shown, but the internal block system is for the outhaul. If it were for the reefing, then you would need to pull a lot more on the reefing line and each foot of reefing line pull would result in much less reefing line being taken up at the clew. This is not the case. Also, there would have to be two block systems in the boom and there is not room for that. OTOH, pulling on the outhaul clearly indicates that the block system is used. This allows you to pull the foot very tight. If your rigging is not like I have described, then you have something quite different than my Z-Spar rig. I think the drawing is a bit misleading. Does your outhaul line route to the cockpit? Mine terminates on the boom. Also at the bottom of the drawing are variations of the outhaul connection to the sail which leads me to think that this drawing pertains to the outhaul and not the reefing lines. I think the reefing lines are only shown for perspective.
In boom block jam
I have to agree with Alan on the possible problem. There should be no difference in the force between the tack and clew with a single line reefing system because they both have the same mechanical purchase. If while under sail the tack and clew both loosened up, then I would go with friction on the cringle.
I have to agree with Alan on the possible problem. There should be no difference in the force between the tack and clew with a single line reefing system because they both have the same mechanical purchase. If while under sail the tack and clew both loosened up, then I would go with friction on the cringle.
Rich...and Alan (?)
on our 35.5s (Alan and mine), the outhaul does not go through the internal blocks. It is one continuous line from mast end of boom through to the outhaul cringle on the main. The floating internal block is indeed a "double" as it handles 1st reef and 2nd reef lines. My '94 model has Isomat spars. Not sure what was used on 376s. I do like what you did with the ball bearing block at the clew cringle on your setup. Alan, do you have any record of what blocks you used to replace the internal floating blocks with? Can you replace it by removing one "end cap" of the boom or do you have to disassemble both ends?
on our 35.5s (Alan and mine), the outhaul does not go through the internal blocks. It is one continuous line from mast end of boom through to the outhaul cringle on the main. The floating internal block is indeed a "double" as it handles 1st reef and 2nd reef lines. My '94 model has Isomat spars. Not sure what was used on 376s. I do like what you did with the ball bearing block at the clew cringle on your setup. Alan, do you have any record of what blocks you used to replace the internal floating blocks with? Can you replace it by removing one "end cap" of the boom or do you have to disassemble both ends?
How did you access block in boom?
I have the same schematic, but could not figure out how to access the block inside the boom. Very interesting thread. I would love to try this out before going to two reefing lines. I currently just hook the cringle at the boom and have one line going to the clew at each reef point. I have heard from others that the single line reefing was too much trouble and very high friction, however, with the block arraingement and a possible improved bearing setup in the boom it may be worthwhile. Would appreciate detail on how you accessed the in-boom system, and what type of bearing blocks you used [Alan], also would appreciate more detail on the block setup you used [Rich].
I have the same schematic, but could not figure out how to access the block inside the boom. Very interesting thread. I would love to try this out before going to two reefing lines. I currently just hook the cringle at the boom and have one line going to the clew at each reef point. I have heard from others that the single line reefing was too much trouble and very high friction, however, with the block arraingement and a possible improved bearing setup in the boom it may be worthwhile. Would appreciate detail on how you accessed the in-boom system, and what type of bearing blocks you used [Alan], also would appreciate more detail on the block setup you used [Rich].
Marc
I was able to replace the internal floating blocks without removing either end of the boom. I used a pair of Harken ball bearing blocks that fit nicely through the aft end cap of the boom(Isomat). I also used 1/4" spectra line for strength and chafe resistance. I replaced the single purchase outhaul with an internal 6:1 cascading system that terminates at the bottom of the boom in a cam cleat just aft of the gooseneck.
I was able to replace the internal floating blocks without removing either end of the boom. I used a pair of Harken ball bearing blocks that fit nicely through the aft end cap of the boom(Isomat). I also used 1/4" spectra line for strength and chafe resistance. I replaced the single purchase outhaul with an internal 6:1 cascading system that terminates at the bottom of the boom in a cam cleat just aft of the gooseneck.
Access to floating block
The Isomat boom has 4 aft sheaves that are used for various lines. If all the lines in use on these sheaves are made slack the single Axel with the 4 sheaves in place can be removed(no tools needed). The reef line must be completely eased to remove the block. The opening is then used to remove the floating block. A messenger line can be tied to one end of the reef line and pulled through the boom. When the block is removed and the reef line separated from the messenger the new block can be installed and the messenger pulled back out again. Repeat the procedure for the second reef. Note: downsizing line size by upgrading line quality like spectra will make a marked difference in friction loss also. Using this upgraded single line reefing system is as smooth as silk. The basic design remains the same, but the reduced friction makes all the difference. PS, Try the Harken 29mm Carbo model # 353 block
The Isomat boom has 4 aft sheaves that are used for various lines. If all the lines in use on these sheaves are made slack the single Axel with the 4 sheaves in place can be removed(no tools needed). The reef line must be completely eased to remove the block. The opening is then used to remove the floating block. A messenger line can be tied to one end of the reef line and pulled through the boom. When the block is removed and the reef line separated from the messenger the new block can be installed and the messenger pulled back out again. Repeat the procedure for the second reef. Note: downsizing line size by upgrading line quality like spectra will make a marked difference in friction loss also. Using this upgraded single line reefing system is as smooth as silk. The basic design remains the same, but the reduced friction makes all the difference. PS, Try the Harken 29mm Carbo model # 353 block
Why not eliminate the double-block?
Looking at Alan's figure (thanks Alan), why not eliminate the double block? One less friction area and possible failure area.
Looking at Alan's figure (thanks Alan), why not eliminate the double block? One less friction area and possible failure area.
Also for Bob.....
Donalex's post above is exactly the setup that my 1997 h40.5 has. His description of how to put in a reef is spot on. The reason I changed to a ball bearing block at the clew is because the friction of the line passing thru the clew cringle made it very hard to pull the sail down to the boom. However, Donalex's reefing procedure is the same one I use even with my clew block.
Donalex's post above is exactly the setup that my 1997 h40.5 has. His description of how to put in a reef is spot on. The reason I changed to a ball bearing block at the clew is because the friction of the line passing thru the clew cringle made it very hard to pull the sail down to the boom. However, Donalex's reefing procedure is the same one I use even with my clew block.
H376 Sketch
This sketch is certainly an option. The down side of this setup is that when the tack reaches the small becket there will not yet be enough force to pull full tension in the clew. Everything downstream of the becket will suffer from lower tensioning force. The addition of a roller block on the clew will certainly help but the final tension at the clew will be less than the tension at the tack. The advantage of the Isomat reefing system is that when the tack reaches its stop the clew can still be tightened flattening the foot of the reefed sail.
This sketch is certainly an option. The down side of this setup is that when the tack reaches the small becket there will not yet be enough force to pull full tension in the clew. Everything downstream of the becket will suffer from lower tensioning force. The addition of a roller block on the clew will certainly help but the final tension at the clew will be less than the tension at the tack. The advantage of the Isomat reefing system is that when the tack reaches its stop the clew can still be tightened flattening the foot of the reefed sail.
I have just posted a photo story on adding blocks
Since several members asked for details on adding a block to the clew (or tack) I have posted the details of the project. See the article "Low Friction Reefing System"
Since several members asked for details on adding a block to the clew (or tack) I have posted the details of the project. See the article "Low Friction Reefing System"
Alan/Rich
Alan, The point about not letting the halyard free and cleating it when the mark comes to the rope clutch is that it prevents the tack block from going as low as the becket. Thus tensioning the reef line can only pull the sail down to the boom at the clew. Once the reef is is I then tension the luff on the halyard to get the required sail shape Rich, In my experience adding weight to a sail's leech serves to make it flog. For this reason I did not add blocks to my clew reef points. If your leech has no tendency to vibrate then it seems a good idea.
Alan, The point about not letting the halyard free and cleating it when the mark comes to the rope clutch is that it prevents the tack block from going as low as the becket. Thus tensioning the reef line can only pull the sail down to the boom at the clew. Once the reef is is I then tension the luff on the halyard to get the required sail shape Rich, In my experience adding weight to a sail's leech serves to make it flog. For this reason I did not add blocks to my clew reef points. If your leech has no tendency to vibrate then it seems a good idea.
Donalex- flog?
My main doesn't flog except when head to a strong wind when dropping the sail. When have you had weight at the leech cause flogging?
My main doesn't flog except when head to a strong wind when dropping the sail. When have you had weight at the leech cause flogging?
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