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Catalina/Capri 25/250 Sailor's Forums

Catalina 25 Specific Forum

mast tuning

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bailey
Deckhand

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10 Posts

Initially Posted - 04/29/2005 : 18:45:06

New spreader boots are installed and the mast is back up and straight both fore and aft and port and starbord using Bill Holcomb's "MAST TUNING" tips. Looking for you seasoned skippers feedback on tension numbers. I know all of you have great opinions as to "the tension numbers" but I would like to be in the ballpark when using my Loos Gage. I measured all the Catalina 25's in my marina and each is different, none of the skippers had a Loos Gage whin they put their mast up and are all waiting for me to get the best answers and tune their boats. Would any skipper that has numbers on his boat share them with me?.....Thanks in advance...Jay

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Frank Hopper
Past Commodore

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Pitcairn Island
6776 Posts

Response Posted - 04/29/2005 : 19:26:27

Which gauge did you get? There is one that is for our shroud size and one that is for our stay size, most people have one or the other and use it on both. I have the stay size and like most people play with it based on my mood. The other day I cranked the uppers to 28 which put a nice pre-bend in my mast. I am going to sail with it that way for a while. Lat year I think I used 23. The fore and back stays are loose. My back stay hardens my forestay when I want it hard and loosens it when I want it loose. The lowers are also a matter of taste. I am running pretty tight on my lake because we have such high wind that a loose rig provides leeward rigging making sine waves. It makes me nervous to see my rig So loose that there is no positive pressure on my spreader. Loos comes with a tuning sheet that emphatically insists that a rig must be tight so the strain is carried by all the rigging at all the time and therefore reduces the chance of failure. most skippers see no issue with the weather plates carrying all the load.

Did not get much of an answer did you? This is probably the most individual decision we all make. Just remember you can change it as often as you like as long as your rig is still up!

Welcome to the board. I hope we are more help on other questions and I look forward to your contributions.

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dlucier
Master Marine Consultant

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Virgin Islands (United Kingdom)
7583 Posts

Response Posted - 04/30/2005 : 09:55:22

Jay,

Like you found out amongst the boats in your marina, standing rigging tensions are like snowflakes,...no two are alike!

If I were you, I wouldn't use someone else's Loos gauge numbers because like Frank said, everyone has a different setup depending on local conditions, racing, cruising, hank on sails, adjustable backstay, gut feeling, apathy,...etc. Some people even adjust there rig tensions depending on the current weather conditions(mostly racers).

What you should do is set up your rig and fine tune it until you find tensions that are suitable for your area and boat use. Now you can read the tensions with your Loos gauge and you will be able to duplicate your rig tension when setting up your rig.

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Alan Clark
Captain

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406 Posts

Response Posted - 05/02/2005 : 11:49:47

Thanks Don & Frank, I was wondering the same thing myself and was going to submit that question and found this! Very Appreciated! I think last year,First year we owned Leprechaun, we set it at 24? But I don't remember therefore the query! Should All the rig be set the same? Back & forestay? Is there a number that could bea general Number for General conditions and than after setting we could play around with it? I also have the Loos tension Guage. Thanks for all your help. BTW, We had our club meeting yesterday and I encouraged everyone with a 25 to join the organisation as We did just for this reason! Thanks.. Alan & Eileen

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dalieva
Deckhand

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Canada
14 Posts

Response Posted - 05/02/2005 : 12:48:17

First of all I would like to thank everyone for the great information. Our 84 Catalina 25 is going in the water this coming Saturday 05/07/05. So I am wondering if anyone would know how much rake and pre-bend should be in the mast?

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Bill Sloane
1st Mate

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USA
91 Posts

Response Posted - 05/02/2005 : 15:30:18

I have to admit I was not aware of a gauge to check rig tension. I have been turning my turnbuckles until they are too tight to turn, my opinion. Where on the web site is Bill Holcomb's MAST TUNING ? Without an adjustable backstay, should you still keep loose forestays and backstays? The foresail will tighten the backstay anyway when it goes up.

Bill
C-25 SR/SK No. 496

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dlucier
Master Marine Consultant

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Virgin Islands (United Kingdom)
7583 Posts

Response Posted - 05/02/2005 : 16:16:28

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Bill Sloane
 ...Where on the web site is Bill Holcomb's MAST TUNING?<hr height="1" noshade id="quote"></blockquote id="quote">

Bill's article on [url="http://www.catalina25-250.org/tech/tech25/snkmast.html"]Mast Tuning[/url] is located in the C25 Technical Tips sections of this website.

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Bill Sloane
1st Mate

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USA
91 Posts

Response Posted - 05/04/2005 : 15:14:37

Don, Thanks for providing an active link to the article on 'Mast Tuning". Once I got to it through the link I was able to find it through the opening page of the web site. The article says that if you rake the mast aft, you get weather helm and if you rake the mast forward you get lee helm. Just to be clear, is weather helm the force on the rudder such that if you let go of the tiller, the boat would point up into the wind, as if to go into 'irons'?

Thanks, Bill.

C-25 SR/SK No. 496

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dlucier
Master Marine Consultant

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Virgin Islands (United Kingdom)
7583 Posts

Response Posted - 05/04/2005 : 18:02:42

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Bill Sloane
 Don, Thanks for providing an active link to the article on 'Mast Tuning". Once I got to it through the link I was able to find it through the opening page of the web site. The article says that if you rake the mast aft, you get weather helm and if you rake the mast forward you get lee helm. Just to be clear, is weather helm the force on the rudder such that if you let go of the tiller, the boat would point up into the wind, as if to go into 'irons'?<hr height="1" noshade id="quote"></blockquote id="quote">

Yes, Bill you are correct...Weather helm results in a boat's tendency to turn up into the wind (helm-to-weather to counteract) with lee helm being the opposite.

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Bruce Baker
Captain

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USA
402 Posts

Response Posted - 05/05/2005 : 10:21:02

This is a topic that has been discussed on this forum over the years, but I have never seen a satisfactory answer given. The tuning guide in "tech tips" is fine as far as it goes, but it doesn't give any quantitative recommendations about how much mast rake you should have or how to tension your rig in different wind conditions, as most tuning guides do.

There's a tuning guide for Catalina 22's on the North Sails website, and from that I've come up with what I did to my boat. I'd appreciate feedback on whether you all think I've done it right.

I start with about 5" of mast rake. My boat is a swing keel, and the Catalina 22 guide says use less for swingers than for fixed keels.

I tension my forestay and backstay (not adjustable) to about "25" on the Model B (number90) Loos Gauge. That's stiff but not too stiff. I also tension my top shrouds the same, making sure that the mast is straight in the column. Using the same Loos Gauge that's not designed (too big) for the forestays, I tension them to (I forget, I think about 18). The back stays are hand tight. I usually sail in light air, so I'm not looking for any pre-bend.

I'd appreciate any critique on my approach.

Thanks,

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Alan Clark
Captain

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406 Posts

Response Posted - 05/09/2005 : 15:40:00

Thanks to all for the information. I tuned my Tall Rig this weekend to comply with the mast tuning article..I did leave the aft lowers a little loose as it says and have not sailed in heavy weather yet. We do that and also race so we will check it on a regular basis.

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oldsalt
Admiral

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USA
578 Posts

Response Posted - 05/10/2005 : 17:49:29

Here's a "trick" you can use when tuning your mast to easily check that it's in column. After you've tuned your upper and lower shrouds, eyeball up the mast slot and if it's not perfectly tuned port and starboard, you'll be able to spot it immediately. If all isn't as it should be, your mast will look like a wet noodle and you'll sail a lot differently on opposite tacks. You really can see very slight imperfections in your tuning.

I like to rake my mast about 6" aft which supplies about the correct amount of weather helm. A certain amount of weather helm allows the rudder to generate lift and will round the boat up if you abandon ship accidentally while single handing. I certainly wouldn't recommend ever raking the mast forward.

Although I set my lowers so that when sailing to weather the leeward lowers have little tension, it's dangerous to set them so loose that your mast exhibits pumping when sailing off the wind.

I keep my forestay very "tight" to prevent sag when sailing to windward and my backstay is rather tight as well, using the split backstay adjuster to match the conditions as necessary.

How tight is tight? Unfortunately I haven't been able to get my boat prepped for launching but I'll check the tension with my guage and report back ASAP.

This setup has served me well since '83.

I hope this helps.

Mark

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jlguthri
1st Mate

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USA
93 Posts

Response Posted - 05/10/2005 : 21:13:57

Page 5 of http://www.westmouthbay.com/errata/Catalina25Manual.pdf is a good read too. Not sure if it is the detail you are looking for though. I'm in the process of doing the same thing, and I think it vague.

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