Boom Track & Boom Downhaul Question

[Ward H]

My O'day 25 has a boom track that gives it about 8" or so of movement up and down on the mast.
When I got the boat there were screw stops at the bottom and at the top of the track. I didn't think the boom needed that much travel so I put a stop so it sat about 3" below the black stripe on the mast. I have a line tied to a hoop on the bottom of the slide that goes down to a cleat on the mast.
I have the line cleated to allow the boom to slide up the track to about mid black stripe. That is the black line in the photo. Ignore the other lines as several shown were testing angles for mounting the hardware to run back to the cockpit.

When I raise the main, the boom does not slide easily up the track. Sometimes it will move up while I tighten the halyard and other times it doesn't until I start sailing and then I will notice it slid up and the downhaul line is now tight. I then point into the wind and re-tension the halyard.
Even spraying it with McLube doesn't help it to slide easily, even if I am manually pulling it up.

I am thinking I should just cleat off the line so the boom is tight against the stop so I can set the initial halyard tension and it won't change. I moved the halyard and reef lines to the cockpit so I don't have to go to the mast to set the main so I don't plan to adjust this boom downhaul when I am sailing.

Am I missing something? Sounds too simple.

 

[LANCE ON CLOUD NINE]

You may already do this, but if the out haul and main sheet are not eased when raising the main, there can be much more friction.
Also the angle of the boom as set by topping lift can make a difference. Good luck.

 

[Bill Roosa]

raising or lowering the boom at the gooseneck is another sail shape control. The outhaul controls the camber of the lower portion of the main. I've only read about the raising and lowering the gooseneck but since I can't do that on my rig I skipped over that part.
I do know that if you have a boom-mast angle of less than 90 degrees you have to loosen the outhaul to lower/raise the main or you get sail stretch in the lower part which can be what you are describing.

 

[Joe]

Either use it as a downhaul by adding a purchase system to the control line, or tap in a couple of screws to fix it in place and forget it.

If you have a properly rigged outhaul, vang and Cunningham the boom downhaul is limited in its effectiveness...... with a loose foot main it becomes irrelevant.

 

[Brian S]

Further to Joe's comments, you should either have a downhaul or a Cunningham. A downhaul, of course, requires a sliding gooseneck like you have. A Cunningham requires a grommet about 6-8" above the tack grommet, and then usually a hook on a purchase line to pull down.

This is an important sail control. It controls the draft position. In lighter winds, for maximum power, the point of max draft should be about 50% of the main foot. In higher winds, this max draft actually gets blown aft wards, which causes more heeling and weather helm. Using the downhaul or Cunningham allows you to move the point of max draft forward to 45-40%. A draft stripe about mid-way up the main really helps to see this.

The Cunningham was developed by Briggs Cunningham. In one design racing boats, the main is hoisted to a fixed point on the mast, the black band. Once there, with a fixed position boom, you can't do anything else with halyard tension to adjust luff tension, and thus the draft point. Also, it's impractical to adjust halyard tension during a race once the main is hoisted and cleated off anyway. So the Cunningham line allows you to play luff tension.

The sliding gooseneck presents it's own problems. Although you don't have to worry about sweating the halyard to pre-strech the bolt rope, you have to be careful of where you hoist the main to. If I hoist too high, the headboard gets caught on the backstay. If too low, well, it's too low.

I use a nifty quick release to set my boom height when the main is not hoisted. http://www.mastgates.com/Home_Page.html#Quick_Release Otherwise, the boom will slide down the mast. The quick release is easier to deal with (for me) than a sail stop.