Swinging Boom while on Mooring Can

[efiste]

There is probably a quick, easy answer (or at least a lot of options), but I cannot seem to find any recommendations online here or at other sites. I have a 1987 Catalina 34. New to me for this summer. I am moored in Chicago's Monroe Harbor as I have been with other boats previously. Because of the mooring, the boat obviously has a fair amount of motion in the harbor. As such, the boom swings fairly regularly back and forth 12"-24" with the mainsheet, topping lift, and boom vang as taught as possible. I am thinking I could rig a line from the topping lift or similar to the backstay or perhaps a line down to other of the jib sheet wrenches, but I was wondering if there was an easy/better option (magic pill?) to stop the swinging. I am worried about both the potential head trauma as well as stress fatigue that could be caused by the regular swinging motion. I have noticed that the boom on a lot of other boats in the harbor do not "appear" to be swaying or not as much, and I do not remember having this happen on my previous boat (which was rigged similar but differently).

Always appreciative of the communities help,
Eric

1987 Catalina 34 #358, s/v Windbreaker

[turbulicity]

May be happening if you are taking wind from dead astern. You can let the boom out a little to one side and tighten the sheet, vang and topping lift there.

[Tempest]

Why not just tie it off somewhere.

I use a bungy cord from the bail on my mid-boom block to the cabin top handrail. The bungy cord is tight but allows a little give.

[MarkSF]

Bungee cord from the aft end of the boom to the backstay. Then you can spare the boomvang, mainsheet, etc from some wear by not leaving them so tight.

[sailortjk1]

Should be easy enough to rig a preventer. I would try a rig something to the toe rail or some other strong point. Between the sheet, preventer, and topping lift you should be able to minimize most of the movement.

Don't you just love Monroe?
I am very familiar with that harbor.

[justified]

efiste
Why don't you use what I have always known as a Monkey line, a line attached to the backstay above the boom with a brass clip that attaches to the end of the boom. It will ease the tension on the main sheet and the topping lift. It should be a much shorter line than the others so there won't be as much swing or pendulum effect. It will also help to pull the boom over on the traveler to one side. You will see them on older boats.
Fair winds
Peter

[Omatako]

Originally Posted by sailortjk1

Should be easy enough to rig a preventer. I would try a rig something to the toe rail or some other strong point. Between the sheet, preventer, and topping lift you should be able to minimize most of the movement.

That's what I do. You should have a preventer anyway so if you don't, make one and use it to firmly locate the boom. Nothing else will work as well.

[jjablonowski]

My (smaller) Catalina of about the same vintage as the OP's came with a "pigtail," a short piece of cable swaged to the backstay with a snap shackle that clipped to the end of the boom.

After years of rocking motion on a mooring, the pigtail frayed and snapped.

Hmmm...coulda been the backstay, I thought. Apparently, so does Catalina Direct, the Sacramento chandler that specializes in parts for these boats. It offers a pigtail option on new backstays it sells, but does not recommend it.

If you're really worried about boom swing, why not fabricate a simple brace -- say, a couple of pieces of PVC pipe hinged into a tall X by a single bolt?

[JKCatalina310]

We have the same issue on our Catalina 310.

My short term fix is to either move the boom to one side with traveler and then crank down the sheet or to use a spare line to tension the boom to one side using a wench or cleat.

My long term plan is to rig a permanent preventer system like this one. I figure this can help with this problem plus it is an easy to set preventer that we can use when cruising or even day sailing if it sets as easy as it claims.

Fair winds

[TQA]

Traveler to one side and a lashing to the oposite side.

You should look at ANY piece of the boat that can move while you are on the mooring and arrange to lash it somehow as the movement wears things. There is a story around somewhere of a boat on a mooring that had a rudder that was free to move and wore out it's pintles in a year.