Downwind Catamaran Sailing

[Eleven]

Novice sailor, with Cat experience.
1. Without a main you will be unable to turn into wind to recover mob or avoid a situation ahead. SIGNIFICANT ISSUE.
2. For true down wind a stay sail set opposite to the main and genoa will bounce the available wind, one to t'other, to keep the genao filled and thus avoiding the shock loads when it re-fills. SIGNIFICANT MAST AND RIG LOADS.
3. Put in the necessary reefs in the main so that it can be handled and is the last sail down. Unless you have a rear mounted mast, a stay sail, and back stays.(I love Prouts).
4. I like the idea of back haul and main sheet tension to support the mast from behind but it does NOT solve the forced turn into wind. This sounds much more like sound sailing advice than lawyer speak to protect the design.

By the way, over 20 kts it was usual to winch the roller reefing line to reduce genoa.
Stay sail was always first up, last down. Not big enough to overpower the engine but boats emerging from marina's were wary of charging across my bows. Same chaps that charge down the motorway in their 4X4's to enjoy motoring down the Solent!

[beiland]

Originally Posted by thinwater

Why a post like this; just to stir things up and to draw attention?

Sorry about that 'tone' in my posting. I've just been contributing to forums since 2001, and I've seen a lot of this lack of reading previous postings before.

[thinwater]

Originally Posted by beiland

Sorry about that 'tone' in my posting. I've just been contributing to forums since 2001, and I've seen a lot of this lack of reading previous postings before.

You are right about that.

Google and forum serches are also a useful first step, for those posting very basic questions (" I'm new to boating. What anchor should I buy?").

[Cruisin Cat]

Originally Posted by Eleven

Novice sailor, with Cat experience.
1. Without a main you will be unable to turn into wind to recover mob or avoid a situation ahead. SIGNIFICANT ISSUE.
2. For true down wind a stay sail set opposite to the main and genoa will bounce the available wind, one to t'other, to keep the genao filled and thus avoiding the shock loads when it re-fills. SIGNIFICANT MAST AND RIG LOADS.
3. Put in the necessary reefs in the main so that it can be handled and is the last sail down. Unless you have a rear mounted mast, a stay sail, and back stays.(I love Prouts).
4. I like the idea of back haul and main sheet tension to support the mast from behind but it does NOT solve the forced turn into wind. This sounds much more like sound sailing advice than lawyer speak to protect the design.

By the way, over 20 kts it was usual to winch the roller reefing line to reduce genoa.
Stay sail was always first up, last down. Not big enough to overpower the engine but boats emerging from marina's were wary of charging across my bows. Same chaps that charge down the motorway in their 4X4's to enjoy motoring down the Solent!

1. If you are running downwind without the main up and need to maneuver....snuff the chute/start the engines.

2. Sailing 8000nm downwind across the Pacific with 3 sails up seems like a good way to unnecessarily wear out gear....and everytime a squall comes by, the person on watch has to deal with 3 sails instead of 1.

I'll stay with 1 sail up front for long downwind passages.

[Eleven]

Quite right, Cruising Cat. The O.P. was concerned with running dead down wind in confined waters, his preference, like most, would be to bear off a bit to keep the genoa? filled.
For long passages I'd do the same, enough sails up to maintain 3/4 of hull speed (in my old Prout).
Note the OP was restricted by advice from the manual on his particular boat.

[webejammin]

Our Gemini 105Mc has 2 head sails one a 150% jib and a 200% screacher with a track to move the tack to windward to use for down wind only. We do have a backstay that works really well. Our best speed on just the screecher sail has been 10 kt's in 18 kt's of breeze. We can also fly our main sail and screecher sail wing and wing with no wisker pole and get great speed out of the true wind.

[Dave]

Originally Posted by Cruisin Cat

I'll stay with 1 sail up front for long downwind passages.

Ditto

Went from Cape town to Cabo Verde - jib only.

Dave L38 #38

[impi]

I sail my Lagoon 440 with just the genoa - topping lift always tightened by cranking in the main sheet. Never observed any problem and she feels very comfortable.....
I do have strong 'bungi / elastic' shock chord holding the short and long side stays together as it prevents any whipping action that could happen there ...... That definitely seems to smooth out the ride.
Watching this post with very keen interest as this was not something I had picked up in my manual?

[krafthaus]

Originally Posted by beiland

I suspect this manual was written by a young lawyer whos looking to protect the manufacturer from ANY mast damage on their vessels.

Meanwhile look at this guy who believes in ONLY jib sailing:
Lyra's Rig

Or here is another fellow who uses two genoas in a unique fashion:
Catbird Suite

Just to clarify, I read this owner's manual on a Lagoon 400 that I chartered in September (I wish I owned the boat, but unfortunately do not) and while I understand the increase in mast loading sailing downwind, I thought the manual was conservative provided wind speed was not excessively high. So agree with beiland, I'm sure there is an element of CYA in writing the manual on the manufacturer's part.

But what is interesting, is in all the posts, nobody (current or past owners and others) mentions hearing of or seeing a catamaran mast that sustained damage in a downwind sail.

In the end, seems it comes down to good and at times, conservative, seamanship when sailing your boat to avoid finding yourself in a situation where you suddenly are at risk if the wind picks up to too high a speed.

Greatly appreciate all the excellent posts in reply to my original question.

[Cruisin Cat]

[QUOTE=krafthaus;812713]
But what is interesting, is in all the posts, nobody (current or past owners and others) mentions hearing of or seeing a catamaran mast that sustained damage in a downwind sail./QUOTE]

That is a good point.
Has anyone actually seen or spoken first hand to someone who has sustained rig damage sailing downwind with no main?

[44'cruisingcat]

Don't they have a topping lift?

[Cruisin Cat]

The view earlier in this thread was that the problem (if there is one) is related to mast pumping rather than absence of aft tension on the mast because a main set for running downwind with travler over and sheet out is not going to provide much "back stay" effect.

So, if there is a problem at all which doesn't seem to be clear yet, it seems to be a pumping problem which should presumably also apply to mono's with backstays.

Still interested to hear from anyone who actually has first hand knownedge of rig damage from running with no main up???

[Dave]

Originally Posted by Cruisin Cat

Still interested to hear from anyone who actually has first hand knownedge of rig damage from running with no main up???

No rig damage, but there could well have been...

Mid September, ~12 hrs south of Grand Cayman, 2:00AM sailing under full jib only (because the main was torn - different story) wind 15 kts, no moon, overcast. Inky black night I got hit by a squall out of nowhere. Within less than a minute horizontal driving rain and gusting to 60 kts. No time to reef the 120 % genoa which was sheeted in hard at the time.

The rig was so unbalanced that the boat simply spun or "weather-vaned" stern into the wind and stayed that way for about 1/2 hour until the wind dropped back down under 40.

There was lots of sea room to run and the jib clew-into-the-wind created a stable situation so I left well enough alone and just rode it out.

I hate to think what would have happened with main up and a balanced sail plan.. something would have to give.

Since then I have become a big fan of sailing jib only when those big cumulus clouds pop way up, the sun goes down and the lightning show starts. I have very few worries under jib only.

Dave L38 #38

[cat man do]

Originally Posted by thinwater

No sailing under jib alone in strong winds. This most likely has to do with suporting the mast againts buckling faliure an pumping, not the strength of the shroud. This is not a mono-vs-multi issue. It is a mast design issue. Even the smallest amount of main will do.

Disagree somewhat and will depend on rig, but,
A headsail pulls from the same area where the the shrouds attach (strong)
A reefed main pulls from an area in the middle of the mast, usually unsupported or not as well supported and it pulls in the opposite direction to the headsail.
Naturally, this will be more of an issue uphill than down.

personally, I found using my cheapest sail on the boat was the best for running downhill, especially square.

For me that was a large second hand symetrical kite in a squeezer sock (1/2 the cost of a heady and 1/8th the cost of the main) by its self leaving the more expensive sail safely tucked away.
(Obviously it came down and was replaced by a tweaked out heady as the wind increased)

For additional support, my spare main halyard (spectra) which was my topping lift, was simply shortened and then cranked tight with the mainsheet.

[Dave]

"Wait... I don't understand.

Are you saying the 120% genoa was completely flagged out dead downwind in 60 kt winds? And you didn't furl it? That sounds weird. One, your jib sheets must be awfully long, or were they flagged as well? Two, I can't see how the sail survived the flogging in those winds. Three, even luffing free, I'd think that a large headsail would exert sufficient forces to endanger the rig or even the boat in 60kt winds. So I guess what I'm getting at, do you consider this a survival strategy that you'd recommend, or just something that happens to have worked once? I haven't been in that situation so this is genuine curiosity.

Thanks,
Martin"

No, not quite ... I never had time to release the jib sheet. The jib stayed tightly sheeted the whole time. I was forced downwind with the squall, clew to the wind. No helm. The sail never flogged. It actually filled quite nicely and behaved itself without "backwinding" - I had a tight leech. Hence my choice to leave well enough alone. At the time I remember thinking that it was far more likely to shred if I took any tension off the leech and foot.

In light of the manufacturer's warning cited by the OP, what I'm saying is that on a cat in seriously gusty conditions offshore, sailing under jib alone is much safer than I expected. Gusty conditions in a catamaran, to me, is about as scary as it gets. With a balanced rig monohulls will knock down, cats will power up until something gives. So yes, in those conditions (Gusty with bad visibility), I believe, sailing a cat under jib alone is a reasonable safety strategy.

This is definately NOT a recommendation to go ahead and feel free to get caught with way too much sail up. However, there have been a few cats capsized by inattentive/inexperienced helmsmen in gusty offshore conditions that may have faired better, as I did by luck, if they were under jib only.

Dave L38 #38