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Old 23-03-2016, 01:45   #31
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Re: Choosing a cat

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Originally Posted by Stumble View Post
What synthetic are you using? I reriged our trimaran two years ago for about 75% the cost of stainless. Including new end fittings. The line will have to be replaced at 5 years, but the fittings should last for ever (anodized aluminium). I haven't priced large HSR dyneema since then, but my A-Cat was just reriged with smaller stuff and it cost less than wire would have.

Weight savings depends on the complexity and number of end fittings. I shaved about 80% of the rigging weight out of the mast on our two boats with dyneema. How significant it is depends on you.
Good question! I'll check with the rigger.

n
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Old 23-03-2016, 07:49   #32
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Re: Choosing a cat

Dux gets expensive when you get into bigger sizes.


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Old 23-03-2016, 09:36   #33
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Re: Choosing a cat

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Dux gets expensive when you get into bigger sizes.


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Colligio Dux is also the most expensive of the HSR on the market. There are other cheaper options, like NER, Alpha Ropes, etc. But it is an expensive option. Personally I prefer it for weight advantages and because I can remake it myself anywhere I am (just keep a piece of line the size of your rigging in a locker with a splicing fid), but it isn't always the cheapest. Particularly the first time around.
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Old 23-03-2016, 09:42   #34
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Re: Choosing a cat

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Greg,

excuse my language, but flying a spinnaker to lift the bows in a real blow running downwind is bull...

You may decrease the load on the bows marginally, but at the same time you are increasing speed, which is a much greater concern in heavy weather conditions. Pitchpoling happens when you surf down a wave and meet its predecessor. And we have had times when we were under naked pole and still could not stop the boat from surfing. Thankfully, it so far never got to the point where we had to deploy our drogue, but it made for some interesting times (and some sleepless nights).

The one thing that I wish we had on out boat is a cutter sail. The difference between our genoa with 50 square meters and our storm jib with 15 is just too big...

Oliver
On a cruising boat I absolutely agree with you. But on a very high performance raceing cat I am not sure. I have almost no time on a boat like this, but it is a concern I would have. Which is why I suggest speaking to the designer (who should know) instead of just making an assumption about something I have minimal knowledge of.

If you think my raising a concern is bull**** well that's your problem.

It certainly wouldn't be the first boat I have sailed that is safer with the spinnaker up going down wind than without. And suggesting dropping the main and going with just the headsail sounds good, unless the rig is supported by the leech tension of the mainsail. At the very high end of race boats you simply cannot drop the main without reducing the safety of the rig because the leech tension is considered in the structural calculations for the mast.

No this isn't common, and I only have sailed a few boats this tweaky, but they do exist, and without knowing what type of boat is being discussed here, or how radical it is it raises a red flag to me.
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Old 23-03-2016, 17:01   #35
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Re: Choosing a cat

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Originally Posted by Stumble View Post
And suggesting dropping the main and going with just the headsail sounds good, unless the rig is supported by the leech tension of the mainsail. At the very high end of race boats you simply cannot drop the main without reducing the safety of the rig because the leech tension is considered in the structural calculations for the mast.

No this isn't common, and I only have sailed a few boats this tweaky, but they do exist, and without knowing what type of boat is being discussed here, or how radical it is it raises a red flag to me.
440 Sailing with Jib only and no Main Sail

"
This is the official response from Lagoon......

The position of Lagoon is clear : sailing downwind without the mainsail can
be dangerous for the mast. Indeed the mainsail, the battens and the tension
of the mainsail sheet are part of the tension balance of the mast.

Sailing with just a headsail means that the mast is not enought "tight by
the aft" and so the mast head is pitching too much.

It is our official statement.

Alexandre Dauberville

CNB-LAGOON "
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Old 23-03-2016, 23:13   #36
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Re: Choosing a cat

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Originally Posted by StuM View Post
440 Sailing with Jib only and no Main Sail

"
This is the official response from Lagoon......

The position of Lagoon is clear : sailing downwind without the mainsail can
be dangerous for the mast. Indeed the mainsail, the battens and the tension
of the mainsail sheet are part of the tension balance of the mast.

Sailing with just a headsail means that the mast is not enought "tight by
the aft" and so the mast head is pitching too much.

It is our official statement.

Alexandre Dauberville

CNB-LAGOON "
Nice one.

I take it Lagoon doesn't encourage one to reef the main, or ease the traveller, down wind.

Thats got take the cake for one of the dumbest things i've read on here, and that is quite a feat.

Oh wait it is near April 1.

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Old 24-03-2016, 10:23   #37
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Re: Choosing a cat

It is well known in dinghy catamarans to never, ever, ever, uncleat the main when the spinnaker is up. Travel down, sure, but keep that mainsheet in hard. This is because the main acts as a 'backstay' of sorts to support the mast.

The same would apply for larger boats. There is also the consideration that the main can act as a blanket to shield the headsail to make for easier, and in some cases, ability to douse at all. That is exactly how Randy Smyth teaches how to douse spinnakers in his 'boat school.' Head deep, blanket headsail with main, douse.

Mr Morwood may have had good luck with dousing his chute with a sock and no main, but I've been in two instances where the main wasn't up, and the sock would not douse the chute (Leopard 38, not my boat. I don't take down my main.)

Reefing still leaves main up for support, and if you don't loosen the sheet (as mentioned above), travelling is ok

FWIW, I have almost 30 years in multihulls. Some people start out in Hobies rather than Optis.
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Old 24-03-2016, 14:41   #38
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Re: Choosing a cat

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Originally Posted by Seaslug Caravan View Post
Nice one.

I take it Lagoon doesn't encourage one to reef the main, or ease the traveller, down wind.

Thats got take the cake for one of the dumbest things i've read on here, and that is quite a feat.

Oh wait it is near April 1.

First, shifting the traveler should have minimal effect on leech tension. Unless you have a track that spans the whole boat, in which case you also likely have a curved track to compensate.

Second, an I can't believe I am having to write this, but as part of the reefing process add back halyard tension, and then sheet on the main to induce some leech tension. If you are not doing so, then a basis sailing school may be in order.

If you think reefing substantially effects the effect the main has in pulling the rig into column then you have been doing it wrong.



AD28,

I didn't realize that it was that common about catamarans. My experience was in big monohull S, but it makes sense with the general lack of a backstay. My cat dinghy experience is limited to A-Class cats without a spin, and boy has it been a learning experience.
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Old 24-03-2016, 14:52   #39
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Re: Choosing a cat

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AD28,

I didn't realize that it was that common about catamarans. My experience was in big monohull S, but it makes sense with the general lack of a backstay.
No it doesn't. It means that some rigs are under specified. And for a production cruising boat, this shouldn't be acceptable.


edit: racing boats are an entirely different proposition. IIRC the old 12 metre AC boats didn't have a backstay at all, the job being done by the main halyard when the sail was down, and by the sail itself when it was up. Fine for a race boat, but not a cruising boat.
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Old 24-03-2016, 14:58   #40
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pirate Re: Choosing a cat

Its Not common on Wharrams for sure.. at least not the 2 I've owned..
However.. these Johnny Come Lately Frenchies...
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Old 24-03-2016, 15:22   #41
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Re: Choosing a cat

44 C, the 12 meter AC boats did in fact use the main halyard as the backstay, to save weight..

Once the main got to full hoist the halyard was lead aft to the backstay purchase.

They must have had some form of halyard lock, or easing the backstay would have seen the luff tension ease.

With the racing upper wind limit reefing wasn't required.

That bought back some fond memories. thnx
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Old 24-03-2016, 15:50   #42
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Re: Choosing a cat

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Originally Posted by StuM View Post
440 Sailing with Jib only and no Main Sail

"
This is the official response from Lagoon......

The position of Lagoon is clear : sailing downwind without the mainsail can
be dangerous for the mast. Indeed the mainsail, the battens and the tension
of the mainsail sheet are part of the tension balance of the mast.

Sailing with just a headsail means that the mast is not enought "tight by
the aft" and so the mast head is pitching too much.

It is our official statement.

Alexandre Dauberville

CNB-LAGOON "
Is using the topping lift as a de facto back stay through tensing the main sheet an option?
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Old 24-03-2016, 18:36   #43
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Re: Choosing a cat

Stumble, I disagree with the proposition that increased weight/displacement increases the risk of capsize/pitchpoling on a catamaran due to reduced acceleration. When beating/close reaching (where there is the greatest risk of wind-induced capsize), acceleration in strong gusts exacerbates the problem as it increases the apparent wind speed and heeling forces even further. Moreover, all else being equal, increased displacement also increases a boats resistance to capsize.

When running or broad reaching, acceleration in gusts does reduce the load on the rig, but the increased speed also increases the risk of pitchpoling - the greatest risk when overpowered in a cat downwind. This, of course, is offset somewhat by reduced bouyancy when carrying a greater load, but still, rapid acceleration when overpowered is not what you need in order to avoid burying a bow!

Heeling in monohulls does ultimately spill off wind and act to some extent as a safety valve and this is precisely why catamarans should be reefed earlier (to the potential gusts). But to suggest that rapid acceleration is a safety valve comparable to heeling on a monohull (except re:forces on the rig downwind, as already mentioned) is not technically correct. The moderately overloaded cat will have reduced performance, but will not be any less safe.

Brad
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Old 25-03-2016, 03:49   #44
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Re: Choosing a cat

Good reason not to buy a lagoon , what a crazy statement , there are a lot of situations when sailing that you will want the main down on a cat and lagoon are stating its dangerous for their rig????
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Old 25-03-2016, 03:49   #45
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Re: Choosing a cat

Quote:
Originally Posted by StuM View Post
440 Sailing with Jib only and no Main Sail

"
This is the official response from Lagoon......

The position of Lagoon is clear : sailing downwind without the mainsail can
be dangerous for the mast. Indeed the mainsail, the battens and the tension
of the mainsail sheet are part of the tension balance of the mast.

Sailing with just a headsail means that the mast is not enought "tight by
the aft" and so the mast head is pitching too much.

It is our official statement.

Alexandre Dauberville

CNB-LAGOON "
This is really interesting. Could we find out which area of the rig their position above is there to protect? I assume its not the chainplates, therefore it must be the mast itself. They don't specify any particular mainsail position (the effect the mainsheet might have on the mast would be in a different area for 3rd reef position as opposed to full sail for instance.) so I'd be very keen to establish which area they feel needs balance / support from the mainsheet.
What about square top mains? Are the saying that the top batton on a square top (which is attached to a car and hence 'loose' vertically on the mast track) helps to significantly support the mast via the main sheet and leach? Seems highly doubtful...unless perhaps they mean the topping lift must be tight as well in order for the load to bypass the square top's top batten. In which case the weak spot is then the topping lifts mast sheave I guess...
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