Aurinko III is a Hunter 240 which I bought new in 1998. I have sailed her fair amount since. Being retired now I am free to spend more time on her. Although I live in France, the boat is in Southern Tuscany in Italy, where I use her to cruise amongst the Tuscan Islands and the coast. Life could be much worse.
Over the years the tenderness of the boat has been a bit of a handicap; my wife and daughters rarely join me for a sail because they don’t like “walking on the bulkheads", so, with more time available, I decided to tune the mast and rigging properly in the hope of controlling things better. A contributor to this forum wrote an excellent article in January, 2002 on 260 rig tuning which was most useful. I bought a gauge for measuring wire tension, checked the rigging, T bolts and toggles on the rigging screws (all in pretty decent condition) and set Aurinko III up so she was horizontal in both the longitudinal and the lateral planes to around 0.2%;
Using the main halyard with a chunky weight on the end I set the mast up so as to be vertical in the lateral plane and raked by 1° in the longitudinal one.
It was when I started snugging down the upper shrouds that my problems started:
1/ the mast started bending as soon as upper shroud tension exceeded 2% of breaking load
2/ to compensate I started snugging down the lower shrouds to keep the mast straight
3/ the lower shrouds built up tension very quickly. With the upper shroud tension of 8% the lowers had to be tightened to 12% of breaking load yet the mast curve was 4 inches – Hunter’s recommended maximum.
By further tightening the uppers until I had reached the limits of the rigging screws I achieved little: upper shroud tension only went to about 10% after 6 extra turns on each of the upper rigging screws. I therefore loosened them a bit, took the tension back down to 8% and considered the job done. No point putting extra forces on the hull if I got no more tension in the shrouds and forestay.
I was impressed and rather intimidated by the tension in the forestay, it had never been as tight as this.
The following day I wanted to lower the mast in preparation for the trip to the crane for launching. No way! The forestay tension was so high that the mainsheet tackle was quite inadequate to pull the mast forward and release the pressure on the stemhead fitting. Freeing the forestay pin and toggle was impossible. Finally I put a rigging screw between the U bolt in the anchor locker and the mainsheet tackle and screwing that down as tightly as it would go. This was still not enough to release the pressure on the forestay toggle and pin so I started loosening up on the upper shrouds, giving a turn on the forestay rigging screw from time to time. After a while I had the rigging loose enough to be able to release the forestay and lower the mast. I doubt whether it’s a good idea to put such forces on the anchor locker U bolt.
The outcome of all this is that I have upper shrouds that are set up to about 5% of breaking load, lowers that are still at around 10% and a forestay which is pretty tight (at least by my standards). Raising and lowering the mast has become far more difficult because the mainsheet tackle is no longer man enough for the job – it needs the help of that rigging screw to overcome the pull of the shrouds.
Aurinko III has a Selden mast, not the usual American one; this may make a difference to tuning procedures.
Let me summarise my tuning problems:
1/ How come that my mast is bending so quickly and needs so much tension in the lowers to respect Hunter bending specifications?
2/ Hunter say that upper and lower shrouds should carry a tension of about 20% of breaking load. How come I can only get 10% on my uppers and the tension in my lowers far exceeds that in the uppers?
3/ How can you tune the mast and rigging in such a way that the excellent Hunter mast-raising and mast lowering system works properly without having to re-adjust the rigging screws each time. My experience is that the tuning process puts far more tension into the forestay than you can overcome using the normal Hunter mast raising system. It seems that you can either have a tuned boat, or you can use the Hunter mast raising system; if you want both then you must be prepared to compromise.
I would be most grateful for any guidance members can offer on these matters.
Finally, one of the obvious measures with a tender boat is to reduce weight aloft. Aurinko III already has DYNEEMA halyards and shackles for this reason. Has anyone experimented with DYNEEMA shrouds and carbon fibre masts?
Many thanks for your help and interest
Tim Kenney
Over the years the tenderness of the boat has been a bit of a handicap; my wife and daughters rarely join me for a sail because they don’t like “walking on the bulkheads", so, with more time available, I decided to tune the mast and rigging properly in the hope of controlling things better. A contributor to this forum wrote an excellent article in January, 2002 on 260 rig tuning which was most useful. I bought a gauge for measuring wire tension, checked the rigging, T bolts and toggles on the rigging screws (all in pretty decent condition) and set Aurinko III up so she was horizontal in both the longitudinal and the lateral planes to around 0.2%;
Using the main halyard with a chunky weight on the end I set the mast up so as to be vertical in the lateral plane and raked by 1° in the longitudinal one.
It was when I started snugging down the upper shrouds that my problems started:
1/ the mast started bending as soon as upper shroud tension exceeded 2% of breaking load
2/ to compensate I started snugging down the lower shrouds to keep the mast straight
3/ the lower shrouds built up tension very quickly. With the upper shroud tension of 8% the lowers had to be tightened to 12% of breaking load yet the mast curve was 4 inches – Hunter’s recommended maximum.
By further tightening the uppers until I had reached the limits of the rigging screws I achieved little: upper shroud tension only went to about 10% after 6 extra turns on each of the upper rigging screws. I therefore loosened them a bit, took the tension back down to 8% and considered the job done. No point putting extra forces on the hull if I got no more tension in the shrouds and forestay.
I was impressed and rather intimidated by the tension in the forestay, it had never been as tight as this.
The following day I wanted to lower the mast in preparation for the trip to the crane for launching. No way! The forestay tension was so high that the mainsheet tackle was quite inadequate to pull the mast forward and release the pressure on the stemhead fitting. Freeing the forestay pin and toggle was impossible. Finally I put a rigging screw between the U bolt in the anchor locker and the mainsheet tackle and screwing that down as tightly as it would go. This was still not enough to release the pressure on the forestay toggle and pin so I started loosening up on the upper shrouds, giving a turn on the forestay rigging screw from time to time. After a while I had the rigging loose enough to be able to release the forestay and lower the mast. I doubt whether it’s a good idea to put such forces on the anchor locker U bolt.
The outcome of all this is that I have upper shrouds that are set up to about 5% of breaking load, lowers that are still at around 10% and a forestay which is pretty tight (at least by my standards). Raising and lowering the mast has become far more difficult because the mainsheet tackle is no longer man enough for the job – it needs the help of that rigging screw to overcome the pull of the shrouds.
Aurinko III has a Selden mast, not the usual American one; this may make a difference to tuning procedures.
Let me summarise my tuning problems:
1/ How come that my mast is bending so quickly and needs so much tension in the lowers to respect Hunter bending specifications?
2/ Hunter say that upper and lower shrouds should carry a tension of about 20% of breaking load. How come I can only get 10% on my uppers and the tension in my lowers far exceeds that in the uppers?
3/ How can you tune the mast and rigging in such a way that the excellent Hunter mast-raising and mast lowering system works properly without having to re-adjust the rigging screws each time. My experience is that the tuning process puts far more tension into the forestay than you can overcome using the normal Hunter mast raising system. It seems that you can either have a tuned boat, or you can use the Hunter mast raising system; if you want both then you must be prepared to compromise.
I would be most grateful for any guidance members can offer on these matters.
Finally, one of the obvious measures with a tender boat is to reduce weight aloft. Aurinko III already has DYNEEMA halyards and shackles for this reason. Has anyone experimented with DYNEEMA shrouds and carbon fibre masts?
Many thanks for your help and interest
Tim Kenney
.
