I have found that having halyard blocks a foot away from the mast cuts way down on slap. I did it accidentally on my main mast. Lines are routed on the cabintop, with a bullseye fairlead where it goes over the edge toward the blocks on the mast collar. I didn't want the friction of the line angling down by ~10 degrees at the fairlead, so I made long soft shackles, which allowed the blocks to rest at the same height as the cabin top, and they went as far back from the mast as they went up.

I'd also add that this was a wonderful digression from my original question....has anybody seen any other problems besides getting a yard or batten hooked behind the halyard?

[Webmaster edit: We're masters of digression, Barry. I've added 'slap' to your title...]

Some of us frap our hallyards etc principally out of consideration for our neighbours!   

Brian Kerslake wrote:Nice one, Paul. :-) The best way I've found to cure the slapping issue is to spiral the 4 mm spare halyard 'mousing line' around the mast. Stops everything slapping.

Ahhh !! A light bulb moment! 

Annie Hill wrote:

Brian Kerslake wrote:Our mast lift slaps once the wind gets up. So David, how do you keep it away from the mast? Is your the traditional arrangement - line down the mast then looped under the sail around the mast? Or a DT special?

At anchor in tidal conditions, I get the same issue.  The only way I can get around it is to use a swifter, but when lying head to wind, it's not a problem.

Ah, the travails of the hearing..... I find LC is perfectly quiet.

Brian Kerslake wrote:Our mast lift slaps once the wind gets up. So David, how do you keep it away from the mast? Is your the traditional arrangement - line down the mast then looped under the sail around the mast? Or a DT special?

At anchor in tidal conditions, I get the same issue.  The only way I can get around it is to use a swifter, but when lying head to wind, it's not a problem.