Swan 36 mast tuning
Dear fellow enthousiasts and the Professor,

I rigged my S&S for the first time last week and would like to have information about tuning the mast. My previous experience is from fractional rigs and I have understood that mastheads are simpler to tune, but would still like to receive exact information on the order, procedure and things to check while tuning.

The mast I have is not original, but for what I know it is exactly like the originals in terms of size, shrouds etc. The boom is different though.

Best regards

Aleksi

Dear Aleski,

a very interesting, simple and illustrated book on this matter has been written by Ivar Dedekam

Fair Winds!

Matteo (38/067 Only You)

Dear Aleksi

Thank you,

I ordered the book from Amazon. Feels like an interesting read in many respects.

Thank you for this Thread, I will also buy the book.

Here is my problem:

We did a mast and rigging refit last winter on our Swan 47 (hull 59). We replaced all standing rigging (mix of original rod and cables) with compacted cables that have higher resistance to extension than normal cable.

The yard put the mast back and did the tuning. When arriving we noticed that we could not close the door toward the forward cabin any more. The yard was ready to adjust the wood of the door and blamed humidity. We said no thank for cutting our door but it took me some while to understand that the shroud were over tightened. We have since reduced the tension and the door could be opened nicely but we still have problem with the saloon floor.

Question:

Is it normal that by pulling the shrouds we have some hull deformation?
Should we go on untightening the shroud until we can open the saloon floor?
Should we reduce the tension when not sailing in the winter?

Thank for your experiences

Dear Ludovic
When the shrouds are pre-tensioned there is some deformation in the hull, but your description suggests that the deformation is excessive. However previous grounding damage may have damaged the structure in the keel area, and causes it to flex more.
I would like to ask whether you noticed to which heeling angle the leeward shrouds remained tight when sailing on the wind? If they did not slack at 30 degrees or more the pre-tension was excessive, if they slacked earlier the structure has softened.
It is suggested that you inspect the structure closely in the bulkhead/floorboard problem area in order to determine whether there is local damage and deformation.

Kind regards

Lars

Dear Lars,
as always, you give a very interesting information that cannot go unnoticed.
Pretensioning is almost right when downwind shrouds become slack around a 30 degrees heel. Is this right? I guess this is also pretty independent of sail surface and wind velocity: given the ballast weight and hull geometry, heel angle is a function of torque only.
I have often thought of purchasing a tension gauge but the ones for the rod size I need are very expensive. You are proposing a much cheaper way and something one can check easily and often.

Daniel, 411/004