Shroud tension for a MAC26M with rotating mast

[Tomfoolery]

600 lb sounds really high. I seem to remember something in the neighborhood of 300-350 lb for the uppers, and maybe 250-280 lb for the lowers. The lowers are adjusted to control the amount of bend in the mast after the rake is set with the forestay and the upper shroud tension is set.

The lee side stays should just about be tensioned when heeled hard. Some folks are ok with them actually being a little slack.

Remember that these stays are big rubber bands, only stiffer. They stretch under increased load, and the lee side stays will unstretch as load is reduced. Ideally you want them to never go completely slack, but these aren’t racing boats so I don’t get too concerned about that unless they’re snapping and banging.

Search on “loos” for some discussion on Loos gauges.

[Inquisitor]

600 lb sounds really high. I seem to remember something in the neighborhood of 300-350 lb for the uppers, and maybe 250-280 lb for the lowers. The lowers are adjusted to control the amount of bend in the mast after the rake is set with the forestay and the upper shroud tension is set.

The lee side stays should just about be tensioned when heeled hard. Some folks are ok with them actually being a little slack.

Remember that these stays are big rubber bands, only stiffer. They stretch under increased load, and the lee side stays will unstretch as load is reduced. Ideally you want them to never go completely slack, but these aren’t racing boats so I don’t get too concerned about that unless they’re snapping and banging.

Search on “loos” for some discussion on Loos gauges.

Thanks Tom. I've started going through loos search... and BOAT posted about the same numbers (300 / 270) but he also referenced "factory spec". I re-checked the manual and old web site... nothing is said about a spec for tension anywhere I can find.

[Tomfoolery]

600 lb sounds really high. I seem to remember something in the neighborhood of 300-350 lb for the uppers, and maybe 250-280 lb for the lowers. The lowers are adjusted to control the amount of bend in the mast after the rake is set with the forestay and the upper shroud tension is set.

The lee side stays should just about be tensioned when heeled hard. Some folks are ok with them actually being a little slack.

Remember that these stays are big rubber bands, only stiffer. They stretch under increased load, and the lee side stays will unstretch as load is reduced. Ideally you want them to never go completely slack, but these aren’t racing boats so I don’t get too concerned about that unless they’re snapping and banging.

Search on “loos” for some discussion on Loos gauges.

Thanks Tom. I've started going through loos search... and BOAT posted about the same numbers (300 / 270) but he also referenced "factory spec". I re-checked the manual and old web site... nothing is said about a spec for tension anywhere I can find.

I don’t want to speak for BOAT, but he may be referring to tuning the way the manual says to and the measured shroud tension you get from that. Or it’s based on 10-20% of the minimum breaking strength of the shroud wire ropes. We had a whole discussion on that some years ago, and I can’t find it now. I might have the numbers written down somewhere, too, but I’ll have to look for that book.

[chipveres]

About not tangling the shrouds: Tie them very loosely to the railings before mast raising. Shoestring with overhand knot or even sewing thread. It's supposed to come loose as the mast goes up.

Chip V.

[Be Free]

Slightly off topic, but since his name has been invoked twice in this thread: I've not seen anything from BOAT in a few months. Has anyone heard from him?