Isomat reefing line length

[Dan Kelly]

Hunter passage 42
Does anyone know the length of line required to replace both the 1st and second reef? The PO had jury-rigged, (hacked) the reefing system.
Thanks
FWFS
Dan

 

[sail sfbay]

Suggest rigging a tag line for your reef lines in accordance with pages 14 and 18 in the attached from the sail through the boom and back to the cockpit, remove and measure.

 

[Dan Kelly]

Thanks for the quick reply. I see the schematic for the reefing but not the length of the lines.
The prior owner shortened the lines. So I don't have the original length

 

[sail sfbay]

That is why I suggested routing a small diameter tag line rigged the way you want to run the reefing lines, remove and measure. That is the process I use whenever I replace running rigging to be sure I buy the correct length. Buy a tag line long enough to replace the other running rigging when it is time to do so.

 

[jssailem]

Welcome to the SBO forum.

@sail sfbay has given you first class advise.

What you find in the manual may or may not meet the need as you see it. It is a best guess for a majority of customers. Often owners discover the lines to long/short or to big/small diameter to feel good and run smoothly through the sheaves on your boat.

 

[Terry Cox]

Ditto the recommendations. We have a hockle in our #1 reef. To remove it requires pulling it out with a tag line. One of those to do projects. Good way to measure the length.

 

[Richard19068]

Thanks for the quick reply. I see the schematic for the reefing but not the length of the lines.
The prior owner shortened the lines. So I don't have the original length

Agree with the others about actual measurement. If the sail has ever been replaced the reef points might not be where they were on the original schematic.

 

[jviss]

Is this the reefing system you have?

I originally thought mine was Isomat, but it turns out it is Offshore Spars; but it may be the same system.

Mine had been horribly hacked. The internal shuttle blocks were missing, and there wasn't enough line to rig it properly. I made a sketch of the system, and measured the length of the boom, the height of the reefing points, the height of the boom gooseneck off the deck, lengths of the line on deck, through the clutches, etc. I then used geometry arithmetic to determine the lengths of line needed. I added 10%, I think, and bought the 3/8" (I think) line, which was, miraculously, on sale at West Marine!

It came out perfect - maybe a little too perfect. Next time I would add 15 or 20% rather than 10%. But, it can be done, if you are careful. Don't forget to account for stop knots, tying lines to the boom at the clew end, and enough line in the cockpit when the sail is up and not reefed.

(I have a pic of the sketch I made, but I'll have to spend some time searching for it.)

 

[Dan Kelly]

Is this the reefing system you have?

View attachment 203497

I originally thought mine was Isomat, but it turns out it is Offshore Spars; but it may be the same system.

Mine had been horribly hacked. The internal shuttle blocks were missing, and there wasn't enough line to rig it properly. I made a sketch of the system, and measured the length of the boom, the height of the reefing points, the height of the boom gooseneck off the deck, lengths of the line on deck, through the clutches, etc. I then used geometry arithmetic to determine the lengths of line needed. I added 10%, I think, and bought the 3/8" (I think) line, which was, miraculously, on sale at West Marine!

It came out perfect - maybe a little too perfect. Next time I would add 15 or 20% rather than 10%. But, it can be done, if you are careful. Don't forget to account for stop knots, tying lines to the boom at the clew end, and enough line in the cockpit when the sail is up and not reefed.

(I have a pic of the sketch I made, but I'll have to spend some time searching for it.)

Thanks. Yes that is the system. I was hoping for a short cut (LOL)

 

[jviss]

Hi Dan, well, at least you know where you are. Do you have the shuttle blocks, i.e., those two-sheave blocks that are inside the boom? I had a hard time sourcing them, and finally got the last two a U.K. supplier had.

I recommend making a sketch, as I did. You'll have to measure your boom, and the height of your reefing points, and the lengths of the runs to the cockpit, or wherever they are handled and cleated. Note that the clew ends go pretty much vertically up from where the end of the reefing line is tied to the boom, and then along the leech of the sail to the end of the boom, in the shape of a triangle.