Shroud tension question

[Gil Huguley]

My local rigger replaced some wires/turnbuckles on my boat. Now I am wondering if he got the rig too tight. Shouldn't the leeward wires go noticeably slack to the touch in a moderate breeze? My previous experience is on a Hobie 16, so that knowledge may not be transferable! The leeward side was always slack on that boat. Thanks.

[Ian McColgin]

Ahoy there,

I almost always tune such that the leeward shrouds a just barely unstressed in a good wind. But then, I mostly sail older wooden boats and have a general interest in keeping the stresses down as much as possible. I figure that if a good wind ends any load sharing between weather and leeward stays, that's good.

There are rigs - the triple diamond Thistle for a small boat example, some hard charging IOR types for big boat examples - that are stressed a bit more highly than that to further reduce real or imagined mast movement.

The big thing is that the mast head (or upper most point of stay attachment) stays above the boat's centerline and that the mast remains in colum under that. Everything else is pretty much commentary.

So, it depends on the boat. But, at a guess, you might be a scootch tight. I don't know how one would get a mast correctly tuned without sailing her anyway. One can replicate a good tuning using tools like the Loos Gauge and you might make a nice start that way on a new boat, but anyone who claims they've done the tune-up without a sail knows something I never heard of.

G'luck

Ian

Ian,

In relation to your response, I have a question. How does one ensure the masthead is aligned directly above the centerline of the boat (beam to beam) and in the middle of the boat (stem to stern)? I have heard that you take a spare halyard or other line attached to the masthead and measure the distance from that to the stem, then compare that measurement to the same halyard led to the stern. However, in order for that to work, the attahment at the masthead would have to be precisely at the center of the masthead no? Side to side I can see it working, since the main halyard should come out of the sheave in the middle of the mast, therefore giving you a good comparison from one beam to the other. But how do you do it fore and aft? And how while under sail, crashing along on your ear?


Jim

[Ian McColgin]

Ahoy Jim,

Fore and aft is certainly not in the center of the boat, exceptmaybe for an exceptional cutter. Certainly not for sloops, yawls, ketches and schooners.

One can adjust the weather helm a bit, taking it out by pulling the rig foreward and adding by pulling the rig back. Usually you have an idea as to where to start but when in doubt start either verticle or however the mast step and partners seem to force things.

Absolutely before tweeking the fore and aft trim of the rig, make sure the boat is trimmed correctly. Water is denser than air and it takes very little down trim at the bow to cancel lots of foreward trim in the rig.

I take the easy way to getting the masts straight athwartships. First, I use a hallyard to move from side to side, typically plunking down at port and starboard chainplates. If you're using the uppers and there are aft swept lowers, be sure you're not fouling the hallyard and getting a false measure. If the boom is already rigged, you may have to walk the hallyard behind the topping lift. Just look up and, as Brion would insist, have a fair lead.

The human hand is wonderfully sensitive and you'll easily feel when you have the same level of bounce at each side.

I double check visually even though the hallyard method is far better than my eye, even helped by a held out square. Remember when you look, you may be decieved by a subtle heel to the boat, background objects, and so on.

One final prejudice from a life with wooden boats. I really hate the nail polish mark or just ease one side approach to derigging in the fall and restepping in the spring. There is no reason the believe that the boat will go back together exactly the same way year after year. Actually, it makes good sense to check the tune at least monthly as the season goes along. Boats are living things and just as I take in or let out my belt a notch from time to time . . . .

G'luck

Ian