How Wide is Too Wide?

[multihuler]

I always thought a wide multihull was a good thing until I sailed a 32' cat which was 25' wide, her sea motion was uncomfortable as she wallowed in the swell

[westsail374]

Reading this thread, I get nightmares about trying to dock in heavy winds with huge amounts of windage on a multi and losing engine power.

CRAP IN THE FUEL!

AIR IN THE FUEL LINES!

Etc., etc.

Yikes.

[downunder]

Yeah.

Get a westsail.

[44'cruisingcat]

Find a marina that uses a sealift instead of a travelift, and width becomes a non-issue.

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[GordMay]

See ➥ Multihull Dynamics, Inc. - News Article

[belizesailor]

Originally Posted by westsail374

Reading this thread, I get nightmares about trying to dock in heavy winds with huge amounts of windage on a multi and losing engine power.

CRAP IN THE FUEL!

AIR IN THE FUEL LINES!

Etc., etc.

Yikes.

Dont panic...as a charter captain I run a lot of different cats and I think that for the typical cruising cat (meaning relatively heavy w fixed keels) the windage issue is way overstated by those not familiar w them. And of course you have twin engines and it is very unlikely they will both go out (although it did happen to me onece...submurged line in both props!).

However on lightweight high performance (boards not keels) multis windage can become a definate issue...w boards up they can become like a leaf on the water!

[Caracal]

Originally Posted by belizesailor

However on lightweight high performance (boards not keels) multis windage can become a definate issue...w boards up they can become like a leaf on the water!

That makes me wonder how effective "spoilers" or "spillers", if you will, would work on the lifted boards. I'm thinking of the ones used by small aeroplane pilots use to prevent the plane from lifting off in an Alaskan storm. It's basically a mesh bag around the wing (board, if applied to a boat) with some foam at the front to spill the airflow.

Obviously, it wouldn't remove the "weathervaning" because an area is an area, but I'm thinking it might prevent some of the sailing at anchor.

In any case, just a thought.

Edit: here's a piccy:

[mark_morwood]

Originally Posted by westsail374

Reading this thread, I get nightmares about trying to dock in heavy winds with huge amounts of windage on a multi and losing engine power.

CRAP IN THE FUEL!

AIR IN THE FUEL LINES!

Etc., etc.

Yikes.

Let me put your mind at ease. Most cruising catamarans are dramatically easier to manage in tight spaces than heavy, full keeled mono-hulls as they have two engines. (I have owned and cruised extensively on both types of vessels).

Two engines gives you a couple of key advantages:
- redundancy (two separate engines and two separate fuel systems)
- maneuverability - two engines the width of the boat apart, lets you do things you would not dream of trying in a mono-hull. If you haven't tried it, a useful analogy is a bob-cat where you can drive one set of wheels forward and one set backwards, spinning on the spot.

Mark.

[mark_morwood]

Originally Posted by Caracal

That makes me wonder how effective "spoilers" or "spillers", if you will, would work on the lifted boards. I'm thinking of the ones used by small aeroplane pilots use to prevent the plane from lifting off in an Alaskan storm. It's basically a mesh bag around the wing (board, if applied to a boat) with some foam at the front to spill the airflow.

Obviously, it wouldn't remove the "weathervaning" because an area is an area, but I'm thinking it might prevent some of the sailing at anchor.

In any case, just a thought.

Edit: here's a piccy:

Interesting idea, but the issue is not lift generated from the board sticking up, but lack of board in the water to stop you blowing around. The answer is usually to just put one or both of the boards part way down. You can try to be very clever and just put one board down to move the pivot point of the boat while maneuvering from one hull to the other, but the few times I've tried it really wasn't worth it.

Mark.

[Caracal]

Originally Posted by mark_morwood

Interesting idea, but the issue is not lift generated from the board sticking up, but lack of board in the water to stop you blowing around. The answer is usually to just put one or both of the boards part way down. You can try to be very clever and just put one board down to move the pivot point of the boat while maneuvering from one hull to the other, but the few times I've tried it really wasn't worth it.

Mark.

I see. I thought "boards up" as if anchored somewhere where the boards down wouldn't be possible, or even (downhill) sailing with boards up.

[Cotemar]

If you stay under 20 feet wide you can fit in almost any travel lift at most any marina.
What we find is that it's not the travlel lift but the lifting well that is to tight to fit in even though there travel lift will lift us.

The bigger the traverl lift the more expensive it is for haul out.

[tamicatana]

Caracal

in my experience a properly sized (length?) bridle will stop anchor-sailing. And you don't have to put the boards full down to get benefit from them

[Caracal]

Originally Posted by tamicatana

Caracal

in my experience a properly sized (length?) bridle will stop anchor-sailing. And you don't have to put the boards full down to get benefit from them

Thanks, I'm only now getting multihulls, but thanks for the suggestion. In my defence, I was responding to a post which mentioned the boards making the boat into a "leaf on the water"

[mark_morwood]

Originally Posted by Caracal

Thanks, I'm only now getting multihulls, but thanks for the suggestion. In my defence, I was responding to a post which mentioned the boards making the boat into a "leaf on the water"

No defense needed - it was an interesting idea.

I found the transition to a multi-hull interesting as you go from being concerned about the width to appreciating the width - whether for stability, or space for relaxing, to distance between the engines for maneuverability, to distance between the bows so an anchoring or mooring bridle is effective.

Mark.

[Caracal]

Thanks, Mark