Running Backstays

[Dockhead]

Originally Posted by daddle

Yes and no. Swept spreaders often make running backstays redundant. The shroud running over the tip of the spreader does push the mast forward. But every spreader has a shroud at its base which does the opposite.

Especially wide and especially swept spreaders are used even in place of a regular backstay on occasion. With the shroud base moved aft of the mast, the shrouds will pull the mast aft at the points where they are fixed to the mast, balancing the forces from forestay tension and keeping the mast from being pulled forward by the forestay and/inner forestay.

[Dockhead]

Originally Posted by delmarrey

Is anyone using Amsteel/synthetics for running backstays?

Dyneema, as part of the original build (and still in good shape after 12 years). Ideal material for this because of absence of stretch and light weight.

[BriRich]

Folks

Mr. Brewer the designer of the Cape North 43 was kind enough to reply to my email. He says runners are not necessary on my boat as the inner stay connects very close to the mast head. Much appreciate all the response I've learned quite a bit.

[delmarrey]

Sabry, Stillbuilding, Jim, Dockhead,
Thanks! That confirms my interest in the use of Dyneema for replacements. Last year I installed Dyneema for my safety lines and so far am pleased with their performance. I'll also be carrying some spare 3/8" for stay/shroud emergency replace if needed.

Having Dyneema for the runners certainly makes it easier to put away when not needed.

[BriRich]

Originally Posted by BriRich

Folks

Mr. Brewer the designer of the Cape North 43 was kind enough to reply to my email. He says runners are not necessary on my boat as the inner stay connects very close to the mast head. Much appreciate all the response I've learned quite a bit.

From Mr. Brewer with his permission:

I did not add runners to the original design as the staysail stay is attached unusually high on the mast. Modern aluminum spars, unless they are tapered above the upper spreaders, have much greater than required strength in that area, so I felt that runners were not essential and would add little to the rig except complexity.

The years seem to have proven me out as I have never heard of a problem with the 43 masting, and your own yacht is probably old enough to stand witness to my theory.

[delmarrey]

Originally Posted by BriRich

From Mr. Brewer with his permission:

I did not add runners to the original design as the staysail stay is attached unusually high on the mast. Modern aluminum spars, unless they are tapered above the upper spreaders, have much greater than required strength in that area, so I felt that runners were not essential and would add little to the rig except complexity.

The years seem to have proven me out as I have never heard of a problem with the 43 masting, and your own yacht is probably old enough to stand witness to my theory.

So what he's saying is fractional rigs are more likely to come down then masthead rigs.

[Auspicious]

Originally Posted by delmarrey

So what he's saying is fractional rigs are more likely to come down then masthead rigs.

No. What he is saying is that all loads must be carried somewhere. Depending on the design, a forestay on a fractional rig boat may be supported by running backs, lowers, or jumpers to lowers.

If you try to carry a load other than pure compression in a slender column bad things can happen (TM) including at a minimum pumping.

For the described boat with the inner forestay landing so high on the mast the offset to the stays and upper shroads isn't a big deal. That part can be treated (not speaking for Mr. Brewer, just sayin') as a beefy cantilever.

[The Goo]

Hi Brian. A bit late but better than never. I own a Cape North 43. Tarangau. Cutter rig with single cross trees. The mast section is original allspar mast from Australia. It clips together in overlapping sections and therefore very strong. We have had Tarangau out running down big seas in 50 knots with the storm jib on and initially 3 reefs in the main. It was our delivery voyage and still learning about shortening sail early. No pumping was observed. When the wind strengthened we dropped the main still no pumping observed when we drove into the troughs. Whilst normally I would advocate running back stays we have not found we needed them and our rigger said that if we got to the point that we needed running backstays with our Nast section then we would have the jib off anyway. I corresponded with Ted Brewer in 2015 so I hope you got a response from him. Dave