Single line reefing conversion details?

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jviss
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Single line reefing conversion details?

This is for a Catalina 36 Mk. I.

Does anyone know the part numbers for the mast exit blocks, a.k.a., sheave boxes, for the boom set up for single line reefing?

Also, any drawings you might have would be sincerely appreciated, particularly around machining of the slots in the boom for the sheave boxes, the reeving of the reefing lines, and how the lines are led down the mast to the deck and back to the cockpit.

Thanks!

jv

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Nimue
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I recently bought the one on the Catalina Direct website. I didn't go to single line reefing but I needed one of the sheave box sets just to put in proper internal slab reefing on my boom. It worked great and was a good deal. I would guess this is a custom part, not a part number you can shop around.

Jason V
Vancouver, BC, Canada

jviss
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Thanks for the quick reply, Jason. Opinion on single line reefing? Also, I'm interested in in what you did - "proper internal slab reefing." Care to share?

jv

jviss
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Rob Kyles
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FWIW, I've set up single line reefing for my #2 reef only. Most times we go straight to #2.
If we need reef 1, the weather is quite mild so it's safe enough clambering around on the deck to get to the luff and leech.
If we need reef 3, then the sail is getting small enough to handle OK, and the leech is inboard enough to reach without leaning overboard.
I leave a line connected to the 3rd reef leech cringle, tied off to the 2nd reef cringle when not used. Haul the second reef in first, then go to the mast and tie down the third reef, move to the leech and tie off there, then to the cockpit to snug up the halyard.

 

S.V. Wind Star

Rob & Margie Kyles:    Auckland ,New Zealand
Mk I  Hull #105 1983   Std Rig, Std Keel

 

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Nimue
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Jviss - that is the one I used. Worked great.

I put this part in the outboard end of the boom and ran the reef lines forward, then out slots that I cut in the sides of the boom near the forward end. This controls the clew in the reef.

The tack I just use a tack hook on the gooseneck and attach manually.

I have my main halyard winch on the mast, so to reef I go up to the mast, and can control the halyard and both corners of the main from there, with much less friction and a lot less stuff bolted to the deck than if I had it all led aft.

Jason V
Vancouver, BC, Canada

jviss
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Thanks, guys.

Jason, thanks again, it really helped. I ordered the boxes, and I happen to have a drawing from Catalina entitled "BOOM MACHINING." It shows the hole and slot details, except it's missing a dimension. Catalina is faxing a drawing, but I won't see it until I next get in to the office.

Catalina Direct sells an un-machined boom extrusion, but only publishes the boom assembly drawing, not the machining drawing.

I have every dimension I need except the distance from the front end (gooseneck end) of the boom extrusion to the front edge of the exit slot for the reefing line.

Maybe if I get stuck someone could measure it for me? :)

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Nimue
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I located mine by measuring how far the boom end fitting inserted, slid the sheave box in far enough for clearance, and drilled the hole for the pin. Then I measured the width of the sheaves, drilled a hole at each end, rough cut the holes with a jigsaw, and filed them out until the plates of the sheave box matched up with the edges of the holes. Couple hours, tops. IMO you want the sheave box as close to the end of the boom as possible.

If you are going to full single-line reefing I imagine the sheave box may interfere with your outhaul tackle, it certainly would with mine but again mine is not stock (in fact my whole boom is about 2' longer than stock to boot!).

Jason V
Vancouver, BC, Canada

jviss
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Thanks, yes, I have pretty much all the detail I need to locate the slots and mill them out. I just have to see if I have a convenient size end mill, i.e., one that's the same radius as the slots. The slots aren't fully dimensioned so I think I'll make a CAD model of the whole thing; not necessary, but fun to do.

If someone can give make a measurement as described above I'll be grateful.

I have drawings that show the internal single line reefing set-up with the internal outhaul tackle, too, so I imagine no problems with this.

jv

jviss
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How do you attach the aft end of the reefing line to the boom? Just tie it around the boom (assuming loose-footed main), or attach a pad eye and tie to that?

Thanks,

jv

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Nimue
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I tie mine around the boom with a loose footed sail. A padeye could work but you'd want to through-bolt it I think.

Jason V
Vancouver, BC, Canada

jviss
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Yes, I agree, thanks.

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Gsmith
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Diagram for reef lines

Gary Smith
93 MK I, Hull #1231
Std rig; wing keel
M35A Oberdorfer conversion
 

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jviss
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[QUOTE=Gsmith;19569]Diagram for reef lines[/QUOTE]

Great, thanks!

Edit: Yikes, I now see that that's a page from the Mk. II manual - who'd of thunk!

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Gsmith
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JV

The diagram came out of my manual which is labeled as the MK1. The MK2 I believe came out with the 94 model year. It was however in that transition period refered to as MK1.5

Gary Smith
93 MK I, Hull #1231
Std rig; wing keel
M35A Oberdorfer conversion
 

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