Rigging Tension - Islander 26

[Old Snipe]

I was doing some pre underway checks on the boat over the weekend and was looking over the shrouds, forestay, and the backstay. They all seemed slack to me so I tweeked the turnbuckles a little. I didn't want to do too much with them for fear of loading the mast in any one direction.....If that makes sense. After doing this, I was left to wonder what more experienced sailboat owners look for. I was told by a couple people to buy a tension gauge and use it whenever I make adjustments. The suggestions themselves only left me with more questions afterwards.

Is rigging tension pretty much standard for all boats when you go by the diameter size of the wire itself, or is it specific to each make and model of boat?

My experience with other types of ( non sailboat ) rigging has always been to measure the deflection according to wire size and span using a spring scale. But this would be all out the window on sailboat rigging when you consider that the mast will flex. I am confused.

Respectfully..... John

[thomm225]

You can do a search on google and get some good answers. There may also be a video on it on youtube.

Also, the guy down at Salty Dog which is about a mile from where your boat is at Cobb's will probably loan you his Loo's Gauge. Btw, don't let him scare you off, he's quite a character. (and he cruised for many years)

If I remember correctly mine are around 440 or so with the forward lowers around 550 for a little prebend which my boat probably doesn't really need.

You can get tons of different answers to your question from percentage of shroud strength to guys saying

"just tighten'm up til yer mast is straight and there ain't no play in the war."

Also, some folks say on older boats you shouldn't tighten the shrouds quite as tight as the original specs do to age etc.

[Old Snipe]

Thanks thomm225.

Finally got the boat over to the Cove Marina yesterday from Scott's Creek in Portsmouth. Wind was flat all day. The little 8 HP Tohatsu did a good job on the 5 1/2 hour trip. About 2/3 throttle making about 3.5 knots. I am happy to have the boat closer to home and not having to drive through the tunnels all the time.

Very fun day overall....dodging container ships.

[GordMay]

Bob Perry can probably advise you, for a small fee.
Web ➥ Robert H. Perry Yacht Designers, Inc.
E-mail ➥ info@perryboat.com
Blog ➥ Yacht Design According to Perry

[thomm225]

Okay, nice. I saw an Islander over at Cobb's this passed weekend I just assumed that was your boat although it didn't have an outboard that I could see.

As for the ships, it seems whenever I really need to cross Thimble Shoal Channel for a straight shot in coming from Kiptopeke etc there are usually one or two of them to dodge with maybe a Navy Ship in the middle of them.

I just give them a very wide berth. I do enjoy seeing them up close though. They are so massive!

[Hudson Force]

Clues to identify problems can appear with a quick alignment and symmetry test:

1. View directly up the sail track to make sure it's a straight line.
2. Stretch a halyard from the masthead to a point on the port rail and make sure that the reciprocal point is reached with the halyard to the starboard rail.

[Suijin]

In the absence of tension gauge, it's a fairly safe bet, once the mast is in column, to tighten the shrouds to "piano wire tight". There are plenty of guides online about the process for getting your mast in column, with the "right" rake or prebend (or non at all), and then checking and adjusting when underway to ensure that the mast is not sagging and remains straight.

"Piano wire tight" is good and tight but not overly tensioned. You want the shrouds to prevent mast movement and to keep it straight, but not overly stress the rig and hull. Then when under sail check the leeward shrouds. They should not be under load but should not be slack to the point where they are floppy. If you have rod rigging you'll get differing opinions about how much wobble is too much...some riggers maintain that flexing of the rod will fatigue it over time, particularly at the heads. One of the best riggers here in Annapolis scoffs at that notion, calling it nonsense.

Tuning can seem a bit like "whack a mole" since the tension on all the shrouds is related...tighten one, and others will likely need adjustment as a result. After a short time those relationships will become clear and you'll have a pretty good sense of what one change means in terms of other adjustments you need to make.

I would not get caught up in using a gauge unless you're racing or want to extract every last degree of pointing when close hauled. Wire does stretch and the boat flexes, temperature goes up and down... I know racers who tune their rig before every race, and it's interesting how much rig tension can change week to week even if they don't touch it. If the mast is straight when you're sailing and the rig is not so tight that it's stressing the boat, it's tuned well.

[Old Snipe]

Thank you everyone,

I guess it all boils down to common sense from what I am reading from these replies. I have a good feel for what might be considered loose or too tight. I will keep an eye on the mast for straightness when ever I tweek the wires. I have zero plans on racing. Just some Chesapeake Bay cruising, and a little anchoring here and there with a couple lines over the side.

[Cheechako]

I pretty much always do my final adjustment while sailing a close reach or to weather. On a cruiser I expect the lee shrouds to be just almost slack or a bit slack. The uppers on the windward side used to straighten the mast then the shrouds. Then just take the play out of the leeside.