Association Forum - Rudder or tuning problem?

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

Rudder or tuning problem?

New Topic

Topic Locked

Printer Friendly

Author

Topic

ekremer
Deckhand

Member Avatar

19 Posts

Initially Posted - 11/04/2003 : 23:22:59

I have a C250 WB with 3rd generation rudder. I have questioned this forum in the past regarding lee helm when using this rudder, but after much fiddling with the tuning, adjusting the mast rake, and making sure every thing is as straight and symmetrical as I can make it, I have noted that the lee helm problem is only present on port tack. No matter what point of sail, the boat wants to turn right. With the beaching rudder, this is not a problem, but helm effort is much higher.(I have not modified the beaching rudder). Does anyone else have this problem or have a possible fix. The boat is easy to control on either tack, but the port tack takes a lot more concentration because there is very neutral helm, with the tendancy to fall off and jibe if left unattended, and it is difficult to feel the wind groove.

Thanks in advance for any help.

Ed Kremer
Ad Lib C250 WB # 146.

Edited by - on

Oscar
Master Marine Consultant

Members Avatar

USA
2030 Posts

Response Posted - 11/04/2003 : 23:45:00

Ed,

Of all the various rudder issues, this one is uniquely yours as far as I can tell. I'll think about this for a while. A few questions.

Do you always have the CB in the same position? What do you do with your motor? Do you have a tiller or a wheel? Do you trailer or have it in the water, ie. can you see if anything is going on below the water line?

Oscar
250WB#618 Lady Kay on the Chesapeake

Edited by - on

Arlyn Stewart
Master Marine Consultant

Members Avatar

USA
2980 Posts

Response Posted - 11/05/2003 : 07:28:31

Ed,

There are several issues that could cause this.
<ul><li>mast not in column </li><li> center board swing pin bore not true </li><li>asymmetry at the rudder </li><li> a hull not symmetrical </li></ul>

The first can be corrected easily. Ensure that the mast is in column. Don't forget that boat balance plays somewhat into this issue. Once the mast is equal distance to the chain plates, place a level on the mast and check for plump and compare to level of bridge deck.

If the bore is not true in the centerboard, differing characteristics will occur on each tack as the angle of attack will not be the same for each. This would not be easy to correct but is possible. It would likely take some machining on the mounts to allow them to be adjusted.

If the pintles are not mounted correctly or the rudder has warp or is mishapened, it will be asymmetrical and lift one direction better than the other.

Hull shape if asymmetrical is a tougher one to deal with... If this were the case, then it could be overcome by actually running the mast out of column. It would take a sensitive feel to provide this tuning but it could be done I think.

This is very interesting, please keep us informed of your discoveries. The clue I would use to approach this is that it doesn't occur with the beaching rudder. This could mean that the 3rd rudder has a problem or that the beaching rudder had a problem for which something else was a problem and the two canceled each other.

I would focus on the former first. Well, actually as you have a beaching rudder... do the mods on it and I'm betting the 3rd will grow dust in the garage.

Edited by - Arlyn Stewart on 11/05/2003 07:32:47

Steve Milby
Past Commodore

Members Avatar

USA
5909 Posts

Response Posted - 11/05/2003 : 08:48:21

Is the motor tilted clear of the water or is the lower unit dragging in the water when you are sailing?

Edited by - on

Frank Hopper
Past Commodore

Members Avatar

Pitcairn Island
6776 Posts

Response Posted - 11/05/2003 : 08:49:40

Can you borrow another third from someone at your club? That would be good data.

Edited by - on

Dave Bristle
Master Marine Consultant

Members Avatar

Djibouti
10005 Posts

Response Posted - 11/05/2003 : 20:31:12

How is the helm on starboard--neutral? Very light to weather? If your engine is tilted, does it drag on port tack? If it's down, well...

Is your board all the way down? If you are very close to a neutral helm on starboard, having light lee helm on port wouldn't be that strange. Maybe you just need to tune for a little more weather helm in general by tipping the mast back a little.

BTW, if we let go of the helm (while falling overboard) on a typical cruising sloop with weather helm, it generally won't turn up and stop--it'll more likely do a 360 and then some. First, it turns up, the jib backwinds, the boat turns quickly through the wind, jibes, and then swings back around--likely to repeat the performance. I guess if you're in the water, that might be better than a lee helm boat jibing away into the sunset!

Edited by - Dave Bristle on 11/05/2003 20:33:07

ekremer
Deckhand

Members Avatar

19 Posts

Response Posted - 11/05/2003 : 23:18:46

Thank you for your thoughts everyone.

Visually, the rudder appears to be hanging straight and is not warped to my eye. The mast is straight, equal distance to the chainplates, the motor is not dragging, and the hull looks OK. The boat is kept on a hydrohoist. My board is usually fully down when sailing. I don't know about the center board swing pin, but the board is and always has been difficult to raise, but no different than usual. I never noted the problem until installing the 3rd generation rudder, but it is possible that the 2nd had so much torque on it that small differences between port and starboard tack went unnoticed. On starboard tack, the helm feels normal, with slight pull on the tiller (not wheel). On port tack, the boat will sail straight for a minute or two hands free, and then will gradually fall off and would jibe if not attended to. I have tried raking the mast back a little but it made no discernable difference. Shroud tension is equal side to side using a Loos gauge. I agree that in a man OB situation, a boat that jibes away is bad news. I think there is probably not much more I can ascertain until I pull the boat out of the water and take it to a shop where the centerboard can be inspected more carefully. And the mod to the 2nd gen rudder may well fix the problem.

Thanks again.

Ed Kremer

Edited by - on

Arlyn Stewart
Master Marine Consultant

Members Avatar

USA
2980 Posts

Response Posted - 11/06/2003 : 00:25:14

Ed, if you have opportunity to have the boat on a lift, here is a very easy to construct incidence guage that can be readied to check the board.

Edited by - on

ekremer
Deckhand

Members Avatar

19 Posts

Response Posted - 11/07/2003 : 22:03:42

Thanks, Arlyn. I probably won't have time to investigate this problem further for a while, but I do appreciate the effort and thoughtfulness of your response.

Ed Kremer

Edited by - on

Oscar
Master Marine Consultant

Members Avatar

USA
2030 Posts

Response Posted - 11/10/2003 : 21:03:47

Arlyn, you say the CB is adjustable?

Oscar
250WB#618 Lady Kay on the Chesapeake

Edited by - on

Arlyn Stewart
Master Marine Consultant

Members Avatar

USA
2980 Posts

Response Posted - 11/11/2003 : 08:13:09

Yes and no... The board is mounted on a large pin which is supported by two blocks each bolted with two bolts. There is little to no play to adjust these blocks but there could be if a problem was noted. Required would be a little machine work to releive the outside surface and elongate holes to provide movement.

Hopefully, a board is not a problem... but if it were, it would be possible to square it up with a little effort.

Edited by - on

Dave Bristle
Master Marine Consultant

Members Avatar

Djibouti
10005 Posts

Response Posted - 11/11/2003 : 12:28:04

If Ed is having trouble raising the board, could that indicate a misalignment of the pin, or something loose on one side of the pin, that could cause the board to be pointing slightly to port, causing the boat to crab to starboard (the lee side on a port tack)?

Edited by - Dave Bristle on 11/11/2003 12:31:47

Oscar
Master Marine Consultant

Members Avatar

USA
2030 Posts

Response Posted - 11/11/2003 : 12:45:36

<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">something loose on one side of the pin<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">

Good point....might want to make haste investigating......

Oscar

Lady Kay 250 WB #618
In the driveway in Behtlehem, PA ready to go anytime.

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.