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Catalina/Capri 25/250 Sailor's Forums

Catalina 250 Specific Forum

Mast Rake when at rest

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Steve Blackburn
Master Marine Consultant

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Canada
1091 Posts

Initially Posted - 06/20/2008 : 21:44:10

At rest my mast rakes back about 6" (curbature towards aft). Under sail it seems to be straight. How should my mast look at rest? Are my lower shrouds too tight maybe? (they don't feel too tight).

Steve Blackburn, Calgary, AB
C250WB - 1999 - Hull 396

Edited by - on

Nautiduck
Master Marine Consultant

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USA
3704 Posts

Response Posted - 06/21/2008 : 00:09:14

I set the mast for about 2-3" rake. Then set the uppers so that you can pull the shroud about 1" with a strong two finger pull at shoulder height. Then set the lowers so they deflect about 3" with a strong two finger pull at shoulder height. If you overtighten the lowers it will pull back the middle of the mast and create reverse mast bend - not good.

When I sail the leeward lower will be loose in a good wind. The uppers are always tight.

Edited by - on

Steve Blackburn
Master Marine Consultant

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Canada
1091 Posts

Response Posted - 06/21/2008 : 00:23:50

Very comprehensive Randy. I think my lowers are too tight then and my uppers not tight enough. After reading the manual I see that my rake should be 1.5 inches forward. I'm about 4" aft right now! (huge reverse bend).

The manual mentions adjusting the forestay. I cannot adjust my forestay (I have a Schaefer). Do you have a means to adjust your forestay?

Edited by - Steve Blackburn on 06/21/2008 00:51:29

Nautiduck
Master Marine Consultant

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USA
3704 Posts

Response Posted - 06/21/2008 : 09:30:35

I think you mean you should reduce the rake by 1 1/2", not that the rake should lean forward 1 1/2". Correct?

I have a CDI furler and I can lift the drum to get at the stay turnbuckle. According to the Snapfurl 700 manual you have the turnbuckle inside the drum as well. Page 6 has the instructions for adjusting the turnbuckle.

[url="http://www.furling.com/snapfurl.html"]Snapurl 700 Manual[/url]

Edited by - Nautiduck on 06/21/2008 09:31:43

Steve Blackburn
Master Marine Consultant

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Canada
1091 Posts

Response Posted - 06/23/2008 : 00:35:49

I reduced the lower tension and got it much better. Sorry about my "rake" terminology, I'm probably not using it right. I reread the manual and now understand what "rake" means. The mast should lean towards the aft. Using the main halyard as a plumb bob I should have a 4" distance between the halyard and the mast bottom. What I was incorrectly refering to as rake earlier was my mast bending aft or forward. So my mast shouldn't be bent at all right?

Before installing my new single backstay, I will make sure that I follow the the tunning instructions in the manual. I don't think it ever was tuned right.

Edited by - Steve Blackburn on 06/23/2008 00:37:14

Nautiduck
Master Marine Consultant

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USA
3704 Posts

Response Posted - 06/23/2008 : 11:21:04

You got it right. As for mast bend the manual says you should aim for 1.5" of it. Pre-bend is achieved by careful interplay of tensioning the uppers and lowers. I have found that if you follow the directions in the manual - to have no looseness in the leeward lowers - that it is very difficult to have pre-bend. For that reason I have my lowers set so that the leeward lower is loose.

Main thing, as you have learned, on the C250 is not to over-tighten the lowers becasue this causes reverse mast bend (bows aft) and this is not good.

Edited by - Nautiduck on 06/23/2008 11:59:27

MartinJW
Navigator

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USA
241 Posts

Response Posted - 07/20/2008 : 22:59:02

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Nautiduck
 
...
I have a CDI furler and I can lift the drum to get at the stay turnbuckle.
...
<hr height="1" noshade id="quote"></blockquote id="quote">

Randy,

When I attempted to do this (to adjust the forestay turnbuckle), I was only able to lift the drum up about an inch before something stopped it. (I think that - maybe - the top of the furling extrusion hits then top of the forestay at the mast.)

Is there any trick to lifting the drum enough to gain access to the forestay turnbuckle?

Thanks!

Martin

Edited by - on

MartinJW
Navigator

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USA
241 Posts

Response Posted - 07/20/2008 : 23:14:03

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by MartinJW
 <blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Nautiduck
 
...
I have a CDI furler and I can lift the drum to get at the stay turnbuckle.
...
<hr height="1" noshade id="quote"></blockquote id="quote">

Randy,

When I attempted to do this (to adjust the forestay turnbuckle), I was only able to lift the drum up about an inch before something stopped it. (I think that - maybe - the top of the furling extrusion hits then top of the forestay at the mast.)

Is there any trick to lifting the drum enough to gain access to the forestay turnbuckle?

Thanks!

Martin
<hr height="1" noshade id="quote"></blockquote id="quote">

Wait, I found the answer!

In my CDI FLEXIBLE FURLER 2 Installation / Operating Insructions (rev. July 2006), page (9):

"If the forestay needs to be adjusted, remove the luff support pin and slide up the furling drum to expose turnbuckle."

I'll give this a try later in the week...

Thanks,
Martin

Edited by - on

bear
Admiral

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USA
909 Posts

Response Posted - 07/21/2008 : 06:42:50

Martin when you get to the point of sliding the drum up it is best to have another set of hands or a device to hold the drum up while you adjust turnbuckle. Trust me from previous experience doing this.

Edited by - on

MartinJW
Navigator

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USA
241 Posts

Response Posted - 07/21/2008 : 12:31:35

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by bear
 Martin when you get to the point of sliding the drum up it is best to have another set of hands or a device to hold the drum up while you adjust turnbuckle. Trust me from previous experience doing this.
<hr height="1" noshade id="quote"></blockquote id="quote">

Thanks, Bear. I'll have some short pieces of scrap wood and/or a helper with me when I try this.

Martin

Edited by - on

AADIVER
Admiral

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USA
966 Posts

Response Posted - 07/21/2008 : 18:17:00

Randy, the distance from the halyard suspended by a weight at the deck level and the aft of the mast is 10" on my boat. Since buying it, basically new in '05, the tuning hasn't been changed. Since my mast is obviously curved aft, how is that affecting sailing performance?

Edited by - on

Nautiduck
Master Marine Consultant

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USA
3704 Posts

Response Posted - 07/21/2008 : 19:52:05

Frank, I am guessing that your mast is not curved aft. Rather it is leaning aft. If it were curved that much you would see the bend very clearly when looking at the mast from the side. Ten inches would be an amazing amount of bend and I doubt very much that you have it. Rather the mast is leaning back too much. You have 10" of rake (mast leaning back) and Catalina calls for 3-4". You adjust rake using the forestay and backstay. Look at the directions I posted on the other thread called "Shroud Tension." Basically you will want to loosen everything and then tighten the forestay to pull the mast forward.

If the mast is raked too far aft, the boat will have excessive weather helm. If it is raked too far forward, the boat will have lee helm. Excess weather helm is detrimental to boat speed and pointing ability. Lee Helm is dangerous because a puff will make the boat head off, exposing more flattened sail area to the increasing wind. For good performance the rake of the mast should be adjusted so that the boat has light weather helm in moderate winds. For us that is 3-4".

Edited by - Nautiduck on 07/21/2008 19:56:22

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