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StSimon
Captain

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USA
298 Posts

Initially Posted - 10/01/2005 : 15:01:56

The owner's manual specifies a 75' mainsheet for a C25. My mainsheet is only 35'.

Why would they specify a 75' mainsheet? That's 3 times the length of the boat !!

How long are your mainsheets?

Fair winds,

Andy, Breakin' Wind, 1984 C25 SK SR

Edited by - on

Leon Sisson
Master Marine Consultant

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USA
1893 Posts

Response Posted - 10/01/2005 : 15:52:30

StSimon,<blockquote id="quote">quote:<hr height="1" noshade id="quote">Why would they specify a 75' mainsheet?<hr height="1" noshade id="quote"></blockquote id="quote">So we could use the mainsheet as an emergency anchor line?

I don't know, they got me on that one too. I think it might have been to make the mainsheet tackle more usefull in raising the mast.

As with the halyards, appropriate mainsheet length is easy to measure. Raise your boom as high as you're ever likely to have it while sailing. You can use the main halyard for a topping lift if you don't have an adjustable one. Swing the boom forward until it contacts the aft lower shroud. Run a piece of line between the upper and lower mainsheet blocks with the traveler all the way to the opposite side of the boat from the boom. That distance is the furthest you're ever likely to have the mainsheet extended. Measure that piece of line, and multiply by the mainsheet purchase (3:1 for all Catalina 25s I think). Add a few more feet for an eye splice, and a tail with stopper knot.

So let's say (15'x3)+10=55. But check it for yourself. Don't just take my word for it. Remember: measure twice, cut once.

-- Leon

Edited by - on

Sea Trac
Master Marine Consultant

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Vanuatu
1357 Posts

Response Posted - 10/01/2005 : 15:58:31

Hi Andy,

Are you sure that was the dimension for the mainsheet? 75' sounds like the dimension for the main halyard, although mine are 90' since they run back to the cockpit. My mainsheet is about 35' like yours, which leaves plenty to spare when running downwind. However, the extra length is useful for lowering the mast when using the boom as the fulcrum (I think that's the right term). Can you point us to where you saw this dimension? Perhaps some editing is in order.

Edited by - on

Derek Crawford
Master Marine Consultant

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USA
3321 Posts

Response Posted - 10/01/2005 : 16:28:33

"My mainsheet is about 35' like yours, which leaves plenty to spare when running downwind."
Are you sure about that, JB? The boom will make almost a right-angled triangle from mid-cockpit position to fully out to leeward. It's 10' long so that makes the hypotenuse the square root of 200 (10 squared + 10 squared) which is 14.142 feet. A 3-to-1 purchase creates 43' +/- and then you have to add the distance from boom end to traveler (probably 3') times 3, plus a tail. I would think that 55' is a bare minimum (assuming that 3-to-1 purchase). (Mine is 60')
Derek

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Sea Trac
Master Marine Consultant

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Vanuatu
1357 Posts

Response Posted - 10/01/2005 : 16:47:21

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Derek Crawford
 Are you sure about that, JB?<hr height="1" noshade id="quote"></blockquote id="quote">
Hmmm...now that you mention it, Derek, no I'm not. Not at all. I was thinking that it was a third as long as my halyards, but two-thirds would make it the same as your 60'. I guess that's more probably the case. Thanks for catching my error, and keeping someone from buying the wrong length line.

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ClamBeach
Master Marine Consultant

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3072 Posts

Response Posted - 10/01/2005 : 18:04:39

On a standard rig, 65' halyards are just about perfect for jib and main.
That's running them back to a clutch and the cabintop winch.

Edited by - on

StSimon
Captain

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USA
298 Posts

Response Posted - 10/01/2005 : 19:09:56

I got it right here on this website under brochures and manuals.

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Bill Holcomb
Admiral

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USA
769 Posts

Response Posted - 10/02/2005 : 10:01:24

The 75 foot length was so that you can use the mainsheet block 'n tackle to help raise and lower your mast.

Bill Holcomb - C25 Snickerdoodle #4839

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Champipple
Master Marine Consultant

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USA
6855 Posts

Response Posted - 10/03/2005 : 08:07:30

Bill –

All of the manuals show the two man grunt push and pull method of raising and lowering the mast. Did Catalina have a specific method in mind?

Leon – you said <blockquote id="quote">quote:<hr height="1" noshade id="quote"> So let's say (15'x3)+10=55<hr height="1" noshade id="quote"></blockquote id="quote">

I’m not 100% certain but the original block and tackle shows a fiddle block with cam (a double) and a single block with becket.

http://www.catalina25-250.org/manbro/pictures/pc10.gif

My bad math would show everything multiplied by 4.

Derek – your 10 foot number is close, but remember that is the length of the sail not the boom. If you add another foot and a half, that would roughly put the sides of the triangle at about 11.5 feet and the full distance from the traveler to the boom at about 16’ 3”. Based on this you need 65 feet with ten left over for sag and tail or 75…

Edited by - on

Bill Holcomb
Admiral

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USA
769 Posts

Response Posted - 10/03/2005 : 10:36:57

Hi Leon,

The idea of using the mainsheet to help raise and lower the mast was to use the boom as a gin pole, release the aft lower shrouds and the backstay - of course you needed to install a couple of stabalizing wisker wires from the extra hole in the upper shroud chain plate to the aft end of the boom - then lower the mast forward toward the bow.

The alternative method was to secure the mainsheet block 'n tackle to the stem fitting and the forestay. Everyone figured out pretty quickly that an "A-frame" was needed too.

The reason that the C25 mast pivot hole is centered (fore/aft) is to allow for either a forward or an aft lowering of the mast. Other Catalina models are set up for only one direction - usually aft lowering.

Bill Holcomb - C25 Snickerdoodle #4839

Edited by - on

Derek Crawford
Master Marine Consultant

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USA
3321 Posts

Response Posted - 10/03/2005 : 11:01:33

"the full distance from the traveler to the boom at about 16’ 3”. Based on this you need 65 feet with ten left over for sag and tail or 75…"
Duane - doesn't that suppose a 4-to-1 mainsheet purchase? Mine is a 3-to-1 and the 60' is more than adequate.
Derek

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Champipple
Master Marine Consultant

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USA
6855 Posts

Response Posted - 10/03/2005 : 15:37:47

yeah, actually it does. somehow I counted the beckett for more than it was actually worth in that equation. what do I know anyway? I have a six to one mainsheet with only 4 blocks actually threaded.

dw

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Leon Sisson
Master Marine Consultant

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USA
1893 Posts

Response Posted - 10/03/2005 : 17:13:35

Bill H,

Yes, that's exactly how I raise and lower my mast with the mainsheet and boom. I'm thinking of shortening the sheet to what I need for sailing (reducing cockpit clutter), and adding a piece of line between the tackle and boom when stepping the mast.

Duane,

I think you counted right in the diagram, but I suspect the ratio of the mainsheet tackle in the diagram doesn't necessarily match how many of the C-25 are/were rigged. If you look down at the parts list, line items #10 & #11 make up a 3:1 tackle, but don't match the illustration. This may be an example of 'artistic license' when the diagram was drawn.

It could be that the parts manual illustrations were created so early in the production that it might not have been all that clear what was being installed on the production line.

When I got my (very used) C-25, I think the mainsheet was a 3:1 tackle, and the vang 4:1. I suppose one could swap those sets of blocks, and end up with a 4:1 sheet and 3:1 vang. And that swap could have occurred when the boat was being rigged at the dealer. I rerigged mine with about 6:1 vang, and a main sheet tackle that can be quickly switched between 3:1 and 4:1.

-- Leon Sisson

Edited by - on

Frank Hopper
Past Commodore

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Pitcairn Island
6776 Posts

Response Posted - 10/03/2005 : 20:32:50

The boom vang was 3:1 from Catalina on all the 25s I've seen.

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dlucier
Master Marine Consultant

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Virgin Islands (United Kingdom)
7583 Posts

Response Posted - 10/04/2005 : 10:14:02

I moved my original 3:1 mainsheet tackle to the vang position (after changing it to a 6:1) then installed a 4:1 mainsheet with a larger diameter line so as to be easier on the hands.

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