FP Lavezzi rigg tension 2% or 3% strech for offshore

[CaptainRivet]

Hi all,


how much should i "tie down" my side stays on the FP Lavezzi for offshore use.
we put chainplate in (for that the rigg was loose) for the crossmember and enforced the whole cats structure by 400%.
The diamond stays stayed untouch and good due to surveyor who is also a racing sailor.
surveyor suggested to go between 2 and 3% on the rigg, one rigger said 3 while 2 other sailors that are ex boat mechanics and very experienced salt necks said to go slightly over 2% as Lavezzi is a light cat that also compensate the forces with a bit more flex. so for offshore use its better if its a bit softer.

one of them helped me to adjust it 3 days ago and at around a bit over 2% he suggested to stop. genua cable is perfectly straight and from far away the mast bend looks right too. so we stoped there.

What do you thing, ok or too soft?
How can i check if ok?


not much know how about rigg but eager to learn.

We used the method where you use a 2m long piece attached on top to side stay and tie down till the stainlesssteel cable streched by 2-3% length.

[fxykty]

Generally with cats (FP might be different!) you tension the side stay(s) sufficiently so that the leeward stay(s) goes soft but not totally loose when you are at the reefing limit. I expect that’s around 3% stretch equivalent.

Depending on how stiff your cat is (generally an FP is not considered stiff, but after your strengthening work maybe it is) you can add additional tension to prevent the side stays from getting loose when dealing with big waves. That will be equivalent to 4-5% stretch and starts risking other issues if your cat isn’t designed for that level of tension.

[CaptainRivet]

Originally Posted by fxykty

Generally with cats (FP might be different!) you tension the side stay(s) sufficiently so that the leeward stay(s) goes soft but not totally loose when you are at the reefing limit. I expect that’s around 3% stretch equivalent.

Depending on how stiff your cat is (generally an FP is not considered stiff, but after your strengthening work maybe it is) you can add additional tension to prevent the side stays from getting loose when dealing with big waves. That will be equivalent to 4-5% stretch and starts risking other issues if your cat isn’t designed for that level of tension.

thanks for your answer.
Thats exactly the point i have no idea what tension the FP Lavezzi is designed for and zspar just tells you the standard 3% thats more related to mono. Its pretty light with 7t for 40ft cruising cat, solid underwater obove foam core. what most said i talked to is better go a bit softer with rig tension offshore with cats as their rigg is more under stress then mono.
True i am newbee regarding rigg but keen on learning

[SailingHarmonie]

I am confused... When you say "3%" what number are you talking about?

I am used to preloading stays on monohulls to between 10 and 15% of the breaking strength of the wire. That's about what is needed to keep the leeward shrouds from going floppy in 20 knots.

So to me, 3% of the breaking strength seems ridiculously low, but that might be a cat thing...

And I am SURE you are not stretching the wire to 103% of is unloaded strength... since 15% of breaking strength is only 0.15% elongation. (1.5mm/meter)