Association Forum - Help Mast Snake

Assn Members Area · Join

Home.

Association Forum

Ships Store

Cruising

Racing

Technical Tips

Photo Gallery - New

Boat Search - Updated

Manuals & Brochures

Swap Meet

Links

Officer Flag Line & Staff

Bylaws & Constitution

Members Area

Join the Association

Notice:
The advice given on this site is based upon individual or quoted experience, yours may differ.
The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.

Association Forum

Username:	Password:
Save Password
Forgot your Password?

All Forums

Catalina/Capri 25/250 Sailor's Forums

Catalina 250 Specific Forum

Help Mast Snake

New Topic

Topic Locked

Printer Friendly

Author

Topic

frog0911
Master Marine Consultant

Member Avatar

USA
1349 Posts

Initially Posted - 03/30/2004 : 20:52:19

While we were out one day I notice I had to move the starboard fairlead back one additional hole more than the port side in order to trim the Jib so the telltales were flying correctly. The problem is caused by mast being out of adjustment, according to my dealer. Today the lake was like glass and I proceeded manual in hand to retune the mast. What I thought should be a simple process, based on previous experience with our C25, ended up taking over four hours and it still is not right according to the manual. Things I noticed were, with all stays and shrouds loose the mast was not in column but bent at the masthead when I sighted up the slug channel and the masthead was bent aft so that a plum bob hung a good foot off the mast at the base. The manual says I am suppose to put this prebend in after adjusting the upper shrouds and just tightening the lowers taking out the slack. What I had to do was tighten the forestay to pull out the bend before tighten the aftstay and put back the four inches required at the base, 1-1/2 at the spreaders. However, no matter what I did I could not get the snake out of the mast slug track. What I finally did was take my Loos guage and adjust the shrouds to the recommend numbers. This did the best of all, but the snake is still there.
I did find out the one thing I don't like about the turnbuckles is having to remove all those cotter keys just to be able to adjust anything related to stays or shrouds. The old style with jam nuts were much simpler to use when adjusting under sail and on the hard.
The other noticeable item is this mast is not as stiff as the one on our C25 and much lighter, probably why it bends so easly.
That's my story, now how about so expert assistance PLEASE.

Frog and The General

C250, Pretty Penny II, #743
FLEET 25
Coronado 15, M-Cube, #3316

Edited by - on

Arlyn Stewart
Master Marine Consultant

Members Avatar

USA
2980 Posts

Response Posted - 03/30/2004 : 22:27:59

Jerry,

The B&R rig or modified version of it used on the 250 is a considerable divergence from that on the C25. With the 25, prebend could be set by tensioning the foreward lowers which of course the 250 doesn't have.

<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">The manual says I am suppose to put this prebend in after adjusting the upper shrouds and just tightening the lowers taking out the slack.<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">

Something is amiss here... because on a B&R rig which has no forward lowers, the uppers are used to set the prebend via the radically raked spreaders which force the middle of the mast forward as the uppers are tightened. This process works against the forestay so in a sense forward pressure on the spreaders can also be increased by tightening the forestay.

While I have no tuning experience on a wk, my comments lean on the many comments posted over the years. A chief point among them is no one has posted success tuning prebend on a wing keel. I don't know that it can or can't be achieved... I'm just repeated what has been offered a great many times, that prebend couldn't be achieved.

Next, I think the book has to be thrown out because the book is mostly written for two conditions. 1. A traditional rig rather than the B&R. 2. The c250 has no cabin bulkheads which in my opinion probably places some limits on the ability of the hull regarding tuning.

Another issue is the rig is not as heavy as the C25 and while this has brought criticism from some c25 owners... they are thinking within the box of the c25 which has more keel loading. The rig doesn't have to be as heavy...and in fact would be wrong if it were as it would add too much weight aloft.

I've not read any accounts of a rig failure yet on a C250 due to loading. They will lay over and round up rather than duke it out with the wind.

A B&R rig is generally not meant to have a backstay tensioner and infact many of them don't even have a backstay. If a tensioner is used on one, it was meant to be on the forestay which would be a pretty neat trick with a furler. The lack of a tensioner then means that the rig will be trimmed firm.... but not tight, remembering the lack of bulkheads. This means of course, that no on the fly tuning can be enjoyed and no loose rig can be enjoyed for faster light air performance because to do so would leave the mast vulnerable to aft bend.

Now to the tuning.

1. Put the boat on her lines
2. Loosen the lowers
3. Snug the uppers and using a halyard, certify that the mast head is equal distance from each chain plate. After this step, all adjustments to the uppers must be done equally to each side.
4. Adjust the forestay and uppers (equally) to provide the reccomended aft rake.
5. Now, bear down on the uppers (equally) and the forestay until they feel moderately firm but not hat band tight. This will have the effect of firming up the forestay as well as the uppers. At this point the goal should be to get a little prebend (forward bow to the mast) but it will probably not be what the manual calls for.
6. Adjust the backstay so that it clears the roach of the mainsail adequately and then stop unless you generally sail in a lot of wind. Hardening the backstay too much will remove all the dynamic tuning inherrant to a B&R rig though arguably there's far less dynamic nature to the mast head rig than the fractional.
7. Snug the lowers which is perhaps the hardest part of the tuning. They need to be tight enough to hold the mast in column under reaching load but not so firm as to pull aft bend into the mast. This will leave them considerably looser than the uppers.

Edited by - Arlyn Stewart on 03/30/2004 23:01:36

frog0911
Master Marine Consultant

Members Avatar

USA
1349 Posts

Response Posted - 03/31/2004 : 00:07:46

I will give that all a retry when I return next week with the new rudder and motor so after I finish I can take her out to see if all is working properly. Your proceedure is close to what I finally actuall did. I do think I have the fore and aft stay to tight right now, but I don't have a 3/16 Loos gauge to check it out and I don't want to spend the kind of money they want for one. My 5/32 I got for $18 at a local boat store, but they have not had any larger size yet.
Thanks for the words of wisdom.

Edited by - on

tmhansen
Captain

Members Avatar

USA
397 Posts

Response Posted - 03/31/2004 : 02:57:49

Frog, I am not exactly sure what the turnbuckles on a 250 look like but they sound like mine, an open body where a cotter pin goes through the male end of each half. I installed rings on each of mine. Since I trailer sail I have to tension the mast each time I launch. The rings stay connected to the boat so I can't drop them overboard, they don't snag lines. You have to use some care not to bend them. If they do get bent I would toss them or use on a less critical part. I plan on making or buying tube covers for the shrouds to protect the rings. Actually I just had a thought. For trailering my wife sewed sleeves of sunbrella with velcro to open and close the tube. We use them to contain the shrouds from the chain plate until they are collected in a bag on deck. It keeps them from rubbing the deck. I can use them to wrap the shrouds. Velcro might snag on lines. I'll have to give it a try.

Edited by - on

Oscar
Master Marine Consultant

Members Avatar

USA
2030 Posts

Response Posted - 04/02/2004 : 16:43:39

Todd,

I also trailer sail. I put a HD shackle between the forward turnbuckle and the stemhead. This allows me to use more travel on the turnbuckle, thus enabling me to loosen it more. I never have to touch the shrouds. There are metal covers on the shroud turnbuckles.

When I secure the mast for the road, I coil the standing rigging, and secure the coils using nylon wire ties. A two dollar bag lasts a year. When it's time to put er up, a small pair of snips cut's em all in a hurry.

Oscar

Edited by - on

Topic

New Topic

Topic Locked

Printer Friendly

Jump To:

Association Forum

Notice: The advice given on this site is based upon individual or quoted experience, yours may differ.
The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.