Mooring Fields and Catamarans

[Lrfiori]

Hi Sailors,

My captain and I are on a track to own a Catamaran in 2 to 3 years. We live in a port town on the west coast. We have been talking to a local who says that getting a mooring in our town is going to be very difficult because Catamarans act very differently in a mooring field than the comparably lengthed monos. And that they have a stronger pull on the mooring tackle. And that a mooring rated for, say, a 38' mono will not be adequate for a 38' cat.

Will you seasoned cat owners please discuss the ways in which cats are different, and any ways that are used to mitigate the differences?

I've been reading this forum for quite a while and am finally making the move from lurking to asking. Thanks!

LF.

[Privleoplag]

The biggest way they act different on a mooring is the cat won't rock and roll nearly as much.

As far as swinging.. everyone's boat swings more than anyone else's. Don't believe me? Just mention your boat swings the most at a happy hour on the shore and everyone will say "no, theirs does".

True.. a cat may have a bit more windage so there may be more effort on the mooring.. but they don't necessarily weigh more, so maybe not so much different effect.

[Oliver L.]

Hi LF,

that's easy...

A cat follows in general the wind when moored, while monos, due to heavier weight and larger underwater area, follow mostly the current. So if you have wind against current it can get rather interesting. Also, due to the higher windage of the cat, the forces indeed will be bigger.

...not that this ever caused us serious problems...

and remember: A Cat can use moorings in shallow water where the monos won't go.

Happy sailing

Oliver

[yardie]

We've moored all over the Med and never saw much difference. Cats don't have weighted keels so they will be the same or slightly lighter than the same length monohull.

[hlev00]

Originally Posted by Oliver L.

and remember: A Cat can use moorings in shallow water where the monos won't go.



Happy sailing



Oliver

Shallower moorings will typically have smaller boats so may not be ready to handle a cat in a blow and may not be spaced for a larger cat. But in the right conditions it does open up more options.


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[ejlindahl]

The anchor selector of the brand I bought says to go one size up if you have a multihull. So for moderately sized cats i would't think anchor size would be an issue in a well maintained mooring field.

[Rapanui]

Have owned 5 cats and 1 tri, 5 of which permanently moored on swinging moorings where the tide can be fairly strong. 4 centreboard and 2 fixed keel. Its a commonly held belief that multis behave differently to monos, in my experience, absolutely no difference and probably better. I think a bridle helps and stops the buoy impacting the hulls in wind over tide situations, and that is definitely a problem for monos.
As for strength, windage will be greater for a multi but the jerk loads lower because of the lower displacement. My principle is that if you are leaving your pride and joy to the mercies of a swinging mooring, then nothing is too strong, you want the heaviest and largest sinker and ditto the chain and the bridle.

[Garold]

Having owned two catamarans, I have noticed differences between them and mono hulls in a mooring field.

The mono hulls seem to mostly react to current whereas the cats were more influenced by wind.

In a tideless/current less bay, the differences aren't too noticeable. But in say a tidal river mooring field where the tide turns the monohull always seemed to go round at the turn of the tide, whereas the cats would behave differently if ther was an opposing wind.

I also noticed that our cats would generally swing around more than a monohull as the keels were shallower. We often used a small drogue off the stern to reduce the swinging.

Mix all this up with a few planing motorboats and closely placed mooring buoys and I understand the concerns.

Garold

[GordMay]

Greetings and welcome aboard the CF, LF.

[rwidman]

Originally Posted by Lrfiori

Hi Sailors,

My captain and I are on a track to own a Catamaran in 2 to 3 years. We live in a port town on the west coast. We have been talking to a local who says that getting a mooring in our town is going to be very difficult because Catamarans act very differently in a mooring field than the comparably lengthed monos. And that they have a stronger pull on the mooring tackle. And that a mooring rated for, say, a 38' mono will not be adequate for a 38' cat.

Will you seasoned cat owners please discuss the ways in which cats are different, and any ways that are used to mitigate the differences?

I've been reading this forum for quite a while and am finally making the move from lurking to asking. Thanks!

LF.

I don't mean to make things difficult, but if you're concerned about getting a mooring in your town, why don't you call or visit the people who control the moorings and ask them?

[Sandero]

Of course other issues.... is some mooring fields have the moorings set rather close. This has an impact on the length of the mooring painter/scope... the requirements for swing... boats swing on unrelated to the motion of other moored vessels' swinging..maneuvering through a tight field with an extreme beamed vessel.

The pressure on the mooring is related to the windage of the moored boat to a large extent.

[Guthrum]

Garold - I'm curious about your use of a small drogue when anchoring. But it does sound like a very good idea. Can you give details about it (size, design, length, etc.)? Or is it merely a small bucket at the end of a rope?

[Lrfiori]

Thanks for talking about your experiences everyone. Of course we'll be talking to locals but I was sitting here on my couch wondering what you all thought. One person in town said the differences are radical and he won't put us on a mooring.


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[Lrfiori]

Guthrum, can you describe the drogue you use (bucket o'cement, or...) and how it affects your vessel's swing? Does it dance nicely with the monos?

[Garold]

Originally Posted by Guthrum

Garold - I'm curious about your use of a small drogue when anchoring. But it does sound like a very good idea. Can you give details about it (size, design, length, etc.)? Or is it merely a small bucket at the end of a rope?

I tried hanging thick ropes and then buckets off the stern but they didn't work too well so I bought a yacht drogue. Max diameter at the opening was about 1.25m and it was about 1.75m long.

It was a reversed cone shape with a hole in the end to let the water escape. Webbing ties allowed me to fasten it to the stern of the boat with a short mooring rope.

The drogue resuced the dancing round the anchor chain that cats modern cats sometimes do as they are high sided and get pushed round by wind. And without substantial monohull keels, have little resistance to the wind.

Another advantage of the drogue was that in a river, the current would pull the boat round much quicker with the drogue and we would more readily align with the monohulls.

But one BIG word of warning.

I woke early to leave an anchorage and forgot the drogue was attached. With my sleepy head on, I reversed over if after raising the chain. It caught round the prop and being very tough it just wrapped the prop and stopped the engine. After an early morning swim I soon freed it everything. Never again. After that I tied a bag to the wheel to remind me whenever I put the drogue out!

Garold