Jury rig for halyards

[seawolf]

Hello all,
For future cruising plans or voyaging offshore
I was thinking of possible jury rig scenarios and the failure of the external jib or main halyard sheaves was one on my list. If the jury rig comprised of a block attached at the masthead, in case of the main halyard sheave, I would worry about the headboard of the main being pulled away from the mast if at full hoist, and a poor lead at the top in the case of the jib halyard.
Since the halyards ride over two sheaves, should over size blocks be used in a jury rig scenario?
Are there any other considerations in this sort of jury rig?
Thanks in advance.
Fair winds.
Bob

[Brion Toss]

Hi there,
Seems to me, the right question is, " Why don't I have internal halyards?". That way, the same four masthead sheaves could fit four halyards, instead of two, so if you broke or skyed a halyard, you'd have a spare. You'd also have less windage, vastly easier belay and winch layout, less slapping on the mast, and half the chance of skying a halyard in the first place. It's not too late to change, unless you have a wooden mast.
But if you must stay with external, it were best if there's a web on the aft face, suitable for drilling a hole in to hang a block from. It has to be far enough aft to clear the head of the main, but, since it is off to one side, can be closer than if it hung from a transverse pin. This "earing" style is also useful for topping lift pendants.
Use the smallest, strongest block you can find, again to keep it away from the primary halyard. A fair lead on the mast could conceivably make for a better lead to the head of the sail, but I think that reefing would accomplish the same thing, if it's needed.
Fair leads,
Brion Toss

[seawolf]

Brion,
Good advise.
At this time having external halyards is causing me to think in this direction so I will look into a block to the side of the mast head as you noted.
Hopefully by the time I am able to break for some offshore cruising, I will be in a position to transition my mast to internal halyards as this sounds like the best way to go.
Thanks for all the help.
Fair winds.
Bob