Trimming fractional rig with straight spreaders

[KultaPossu]

I have been sailing on a 33foot one off (there is no other boat of this model) boat with fractional rig for couple of years now, I have been trying to learn how to trim her better.

Some info on the rig;
The mast is about 17meters in height
Fractional rig the forestay is about 2.5meters from mast top
2 Straight spreaders
All stays (shrouds?) (3 each side) come directly down (not aft or forward of the mast)
Running backstays with two connecting points on the mast, the forestay and about half way up the mast
Babystay connecting to mast about on the first set of spreaders
Backstay to mast top ofc
Backstay, babystay and kikker are hydraulic


I am trying to figure out how I should use these stays for trimming her and also want to learn how to not bring the mast down, or how to bring it down so I know what not to do.
I'm wondering if the mast can stand on only the backstay or do I always need the runners and what is the function of the babystay other than prevent pumping, do I need it?


I thank you for any advice.

 

[Refueler]

Can you provide a general side on plan or photo ... I find strange your :

"All stays (shrouds?) (3 each side) come directly down (not aft or forward of the mast)"

 

[KultaPossu]

Can you provide a general side on plan or photo ... I find strange your :

"All stays (shrouds?) (3 each side) come directly down (not aft or forward of the mast)"

I was just informed that those are called inline shrouds, I don't have a plan or any photos where those can clearly be seen.

 

[Biggles Wader]

The confusion is if the three shrouds come directly down, not forward or aft of the mast, do they all attach to the same place/chainplate? Surely one is angled a couple of feet forward and the other aft.

 

[HenrikH]

My experience, from Luffe 44, the running backstays are most dominant: tighten up as wind increases on headwind, slacken when running. If you can control the intermediates, put a bit of load in weak winds to increase sail power. (Luffe also had all stays running full length, about 1 inch apart at deck - easier to adjust when you sail for the mast stand straight sideways)

 

[KultaPossu]

The confusion is if the three shrouds come directly down, not forward or aft of the mast, do they all attach to the same place/chainplate? Surely one is angled a couple of feet forward and the other aft.

Yes, they all attach to the same place and chainplate (within 5cm). I found a pic where they can be seen.

 

[KultaPossu]

My experience, from Luffe 44, the running backstays are most dominant: tighten up as wind increases on headwind, slacken when running. If you can control the intermediates, put a bit of load in weak winds to increase sail power. (Luffe also had all stays running full length, about 1 inch apart at deck - easier to adjust when you sail for the mast stand straight sideways)

The intermediates tighten with the running backs but I can adjust them littlebit, but there might not be enough purchase to do that when they are loaded, I'll see to it on next sail. Thank you

 

[William_H]

This seems to be a standard racing rig of 20 or 30 years ago. 2 questions you ask are firstly and important how to make sure mast stays intact and vertical. In light winds the back stay should suffice but as soon as there is any load on the rig your concern is integrity of the mast with the risk of it getting out of column in fore and aft direction. The baby stay working against the running back stays will support the middle. Usually top part of runner will go to forestay point while a branch will go to lower spreader point. This lower branch is adjusted in length to give an appropriate and shared pull back to the lower point. I think the essential thing here is to check the shape of the mast for bend when under power. A slight middle forward may be ok but essentially it should be straight up to forestay.
Now the back stay can give a bend to the top half of the mast. This can allow the top of the main sail to fall away to leeward so relieving heeling pressure. It may also take some camber out of main sail.
One boat I have sailed on a Farr 40 from Admirals cup days had this rig (later changed to swept spreaders aft chain plates.) It had originally a load cell in forestay so tension of runners and back stay could be set precisely. It had a baby inner forestay only connected when conditions need it. ie long tack in rough water. You might want to try to get a consistancy of runner tension I guess by getting a consistent load on winch handle on runners.
I think other wise all tuning tricks will apply to this rig especially trying to get minimum forestay sag in stronger winds.
This old boat (True Blue) I think ca. 1987 was top of the range at the time. (shipped 10000 miles to UK for Admirals cup.( and did well) Made of carbon fibre. Had full Band G instruments including doppler water speed, rod rigging and a window in hull so you could see the folding propeller. Bare internals a toilet sitting bravely in open hull area and pipe berths.
Anyway now mostly unloved. If I were younger I would have bought it. ol'will

 

[KultaPossu]

This seems to be a standard racing rig of 20 or 30 years ago. 2 questions you ask are firstly and important how to make sure mast stays intact and vertical. In light winds the back stay should suffice but as soon as there is any load on the rig your concern is integrity of the mast with the risk of it getting out of column in fore and aft direction. The baby stay working against the running back stays will support the middle. Usually top part of runner will go to forestay point while a branch will go to lower spreader point. This lower branch is adjusted in length to give an appropriate and shared pull back to the lower point. I think the essential thing here is to check the shape of the mast for bend when under power. A slight middle forward may be ok but essentially it should be straight up to forestay.
Now the back stay can give a bend to the top half of the mast. This can allow the top of the main sail to fall away to leeward so relieving heeling pressure. It may also take some camber out of main sail.
One boat I have sailed on a Farr 40 from Admirals cup days had this rig (later changed to swept spreaders aft chain plates.) It had originally a load cell in forestay so tension of runners and back stay could be set precisely. It had a baby inner forestay only connected when conditions need it. ie long tack in rough water. You might want to try to get a consistancy of runner tension I guess by getting a consistent load on winch handle on runners.
I think other wise all tuning tricks will apply to this rig especially trying to get minimum forestay sag in stronger winds.
This old boat (True Blue) I think ca. 1987 was top of the range at the time. (shipped 10000 miles to UK for Admirals cup.( and did well) Made of carbon fibre. Had full Band G instruments including doppler water speed, rod rigging and a window in hull so you could see the folding propeller. Bare internals a toilet sitting bravely in open hull area and pipe berths.
Anyway now mostly unloved. If I were younger I would have bought it. ol'will

It probably is yeah, it might be even older but it also might have been replaced at some point. Thanks for this it helps a lot. Do you have any idea what loads the runners could get?
Currently the runners are on four times purchase and locked with a cam cleat, but they make a pretty worrying noise when under spinnaker in stronger winds (over 12m/s). There is also winches for them but they aren't used (I sometimes secure the runner to the winch as well). This alteration has been done probably in the past 20 years by someone else to make her easier to sail with less crew. I'm wondering if I should trust this singular cam cleat to keep my mast upright or not.

 

[William_H]

It probably is yeah, it might be even older but it also might have been replaced at some point. Thanks for this it helps a lot. Do you have any idea what loads the runners could get?
Currently the runners are on four times purchase and locked with a cam cleat, but they make a pretty worrying noise when under spinnaker in stronger winds (over 12m/s). There is also winches for them but they aren't used (I sometimes secure the runner to the winch as well). This alteration has been done probably in the past 20 years by someone else to make her easier to sail with less crew. I'm wondering if I should trust this singular cam cleat to keep my mast upright or not.

I would have thought one would use winches for runners even with 4 purchase tackle. No idea what loads but as I said just check the look of the mast under load.
ol'will

 

[DoubleEnder]

That’s a big rig for 33’. What is the noise that the runners make? What are they made from, wire?

 

[DoubleEnder]

Don’t trust that cam cleat , I wouldn’t. If it does fail it will be expensive