Shroud tension Loos Tension Gauge 300# tight

[JeffJuneau]

I have read through about every Mac post on shroud tension for a 26M, and I have a new Loos Co. gauge that includes the scale for the Mac’s 5/32 shrouds. Setting the outer long shrouds at 300 lbs was quite difficult with the shroud adjustment tool provided by BWY. It is just about as difficult to get the inner shrouds to 220 lbs. The gauge is properly lubricated, and I have no reason to believe it is not accurate. From the cumulative posts on 26M shroud tensions, it sounds like the consensus tension is 300-325 lbs for uppers and 275 for lowers. I guess it is a good thing I invested in this gauge because my current tension is way higher (perhaps double) the amount I previously used since 2020, when I bought the boat. I am anxious now about too much tension on the upper shrouds. The rotating base still moves, but I must apply a lot more force to move it by hand. I lubricated the washers before I raised the mast. I am not worried about the pressure on the washers, because it still turns either way with the same effort. I’d like to know if I am making a mistake by setting the tension this high. Thanks! JeffJuneau

[Jimmyt]

I think so. But, I haven’t checked mine with a gauge, so I can’t be 100% sure. But typically rotating masts are not rigged tight in my experience.

The head stay is intended to be fastened by hand. So, I’m not sure that will be possible with the shroud tension that high. Maybe, give it a try and see.

On the flip side, if you aren’t trailering, the higher tension in your head stay will give better head sail shape and better furling action. My head stay with furling Genoa has a definite droop - in spite of being somewhat difficult to pin.

Beside rig tension (I would argue more important than rig tension), you need to pay particular attention to mast rake. This will impact your ability to tack, cause excessive helm (weather or lee), and/or cause premature round-up.

[JeffJuneau]

Thanks for your information, Jimmy. I really want to avoid damaging my rig or having it come down during a windy day. In the last 4-years the furled jib on the forestay of my 26M, always had a bit of a droop to my forestay. Now, with the tensions set at 300 lbs (uppers), that droop is gone. Again, in the past, the lee shroud would sometimes be looser than the windward shroud, but not flopping around. Now with all the higher tension, all shrouds stay tight on any tack. I could still furl and unfurl the jib with the lighter tension, but now with the higher tension it is even easier to furl/unfurll. Also, under the lower shroud tensions pinning and unpinning the forestay was very easy, and did not require very high tension on the Macgregor brake/winch. With the outer shrouds set at 300 lbs, I actually had a hard time getting enough pressure on the brake/winch to unpin the forestay. For transport, I loosened one of the long stays a notch, and then retightened it after pinning when I set my Mac up at the harbor. As far as I can determine the forestay set point (I use BWY’s recommended setup on their 5/32 forestay) is what sets the rake, not the shroud pressure. My mast looks like 90 degrees from waterline. Yes, it has some weather helm that causes round up in strong winds, but I wouldn’t want a lot less weather helm, with our gusty winds here.

[Jimmyt]

Sounds like your shrouds were too loose to start with. Pinning my forestay is almost a 2-person job - even with the mast raising winch tight. But my forestay still droops. The forestay length is what sets your mast angle. The length is changed by adjusting the furler attachment (or forestay attachment if you have a hank-on head sail.

This is the recommended setup for the mast. Best to check against these measurements to verify what your eyes are telling you. Also, note that the manual doesn’t give any shroud tension numbers. It just says “try to make them snug”. Then later it discusses putting a 1” bend in the mast using shroud tension…. I ignore this. I get the mast rake where I like it and get the rig snug (where I can just get the forestay pinned; and call it good.



If I remember correctly, some owners have installed adjustable backstays to help take the droop out of the forestay. But, what you’ve done seems to have improved your sailing experience; so congratulations. It’s all about finding the combination that works for you.

Most of us don’t race our boats, so efficiency is not a priority. But, weather helm (or lee helm) is basically hydrodynamic braking. A very slight amount of weather helm makes the boat “safer”, as you indicate. It’s best to not have too much, though.

[JeffJuneau]

Thanks Jimmy, I forgot which pdf included that diagram and length from mast raising hole to front of rubrail in the 26M manuals. I know I have it somewhere in my collection of mac stuff. I agree that there is no substitute for an actual measurement to get the correct mast forward/aft angle. Thanks, Jeff