Why Do Catamarans Motor Nearly 100%

[Sail IC]

Here is a video I took a couple of months ago. As you can see, there are three monos all going by motor where I'm sailing my cat.

Nice wind, 10-15 knots if I remember right doing around 7-8 knots speed comfortably overtaking the closest mono (if you look at the land behind the mono, you'll see I'm faster, 1-2 knots). The mono you see ahead at around 12 sec, overtook that one too.

We're just about to have some coffee.

http://youtu.be/MJG4GelYEJ8

[Kenomac]

Some thoughts and recent observations on anchorage stability as it relates to the multihull vs monohull experience, the rock and roll of it all:

In a relatively calm anshorage, I've haven't noticed any difference between a boat like ours or any of the larger Beneteaus, Hanse, or etc and the many catamarans around. All seem to rock about the same... Which isn't much if any. The powerboats and trawlers on the other hand swing back and forth with the smallest wake.

In an anchorage with small swells, the catamarans are definitely more stable and less likely to begin the side to side rocking. I get seasick just looking at the powerboats and trawlers in those conditions. Still not too bad in our boat, but the smaller under 45ft sailboats... Yuck.

In a really rocky anchorage, 2-3 ft swells coming through with wind from the side. Certainly not a great situation in any boat, but then... Even the multihulls tend to leave. Less rocking than the monohulls, but probably due to more rocking that their used to. I have in the past stayed in this type of condition even after watching several catamarans leave that were rocking, but it was gross and I don't blame them for leaving.

Fortunately, nothing but calm anchorages for us this season, with only one night over the past two months that I'd consider a moderately rolly anchorage. Most boats, multi and mono stayed on.

We're getting much better at selecting the right anchorage condusive to the weather and swell conditions, making the stability at anchor issue almost mute. Now I just need to find a way to have more of a panaramic living room view like on a catamaran. :-)

[hoppy]

Originally Posted by Kenomac

Now I just need to find a way to have more of a panaramic living room view like on a catamaran. :-)

Just sit in the cockpit around the table under the bimini.

Sitting inside is for colder climates and ugly people

[colemj]

There is one other anchorage condition that can occur (Portobello Panama is notorious for this) - seemingly no waves at all, but a regular very long wavelength, small height swell. You cannot even tell that there are "waves" when looking at it - everything looks flat.

In this conditions, mono's slowly get into harmonic resonance with the almost non-existant swell until they are rolling violently from rail to rail. Then they abruptly stop and sit still for a bit until they slowly begin to get into resonance again.

Every boat will find a different resonance point depending on its length, weight, draft, etc, so that individual monos will begin to seemingly randomly roll their guts out and stop while others near them stand still - until those boats begin their resonant harmonic. There is no size or type of mono that will escape this - we have watched large commercial ships fall prey.

Those in catamarans stand on deck scratching their heads trying to figure out what the hell is going on with all the monos in a flat-water anchorage.

We have experienced these anchorages many times, but it took me quite a while to figure out why all those monos were rolling their guts out, then stopping, then rolling, etc.

Mark

[Kenomac]

Mark,

You hit the nail on the head with your post. Some boats get hit by the harmonic rhythm more than others, then suddenly at times everyone is rockin'. It's like you wonder if the spreader is going to touch the water. The worst one here in the Med for us was just south of the Ibiza Airport and another was Soller, Mallorca. Both can great places except when there's a swell from the north in the case of of Soller or south in Ibiza, then its terrible.

I think primarily do to well selected anchorages this season, we haven't experienced it... yet. Our time will come. The anchorages near Palma Mallorca and the north shore were notorious for this, and there was no place else to go.

Ken

[a64pilot]

I've only once gotten into this harmonic you guy's speak of, I got into Clearwater late on night, about 10:30, and after being run into by the local CBP, photographed, video taped, played 20 questions etc. I just gave up and anchored out just before the big bridge. I was beat so I just tolerated it, but I am sure just bringing the stern around a little with a stern anchor would have stopped it.
Only real extended Cat experience I have is on a power Cat, this one Home | Aqua Cat Cruises
We spent a week I think on it, diving. It essentially didn't roll, but it did pitch just as much as any boat, and it did have a "different" motion going to weather as first one hull would hit a wave, then the second one did. Kind of a ta-dump kind of feeling, felt like a Harley sounds at idle if that makes any sense, but one night we got into some pretty big waves, and occasionally one of them would hit the belly of the boat, felt like we ran aground when that happened, slammed pretty hard. How often does this happen in a sailing Cat?

[weavis]

Originally Posted by a64pilot

I've only once gotten into this harmonic you guy's speak of, I got into Clearwater late on night, about 10:30, and after being run into by the local CBP, photographed, video taped, played 20 questions etc. I just gave up and anchored out just before the big bridge. I was beat so I just tolerated it, but I am sure just bringing the stern around a little with a stern anchor would have stopped it.
Only real extended Cat experience I have is on a power Cat, this one Home | Aqua Cat Cruises
We spent a week I think on it, diving. It essentially didn't roll, but it did pitch just as much as any boat, and it did have a "different" motion going to weather as first one hull would hit a wave, then the second one did. Kind of a ta-dump kind of feeling, felt like a Harley sounds at idle if that makes any sense, but one night we got into some pretty big waves, and occasionally one of them would hit the belly of the boat, felt like we ran aground when that happened, slammed pretty hard. How often does this happen in a sailing Cat?

Bring ear muffs. Some cats are prone to slamming. Like the boat is falling apart................. after the first couple of years you get used to it....... or go buy a Cat with a bigger centre clearance.

[44'cruisingcat]

Originally Posted by colemj

Those in catamarans stand on deck scratching their heads trying to figure out what the hell is going on with all the monos in a flat-water anchorage.



Mark

I had this exact experience, in reverse! At 2 am, on our old mono, rolling our guts out in nearly invisible waves, watching a nearby cat sitting dead still, and wondering what the hell was going on...

[donradcliffe]

The worst rolling I ever did was on the pilings in the Brisbane river every time the ferry cats went by. Their wake didn't look like much, but it was the only place in the world where the coffee got knocked off my table.

[markpierce]

Originally Posted by colemj

...
Every boat will find a different resonance point depending on its length, weight, draft, etc, so that individual monos will begin to seemingly randomly roll their guts out and stop while others near them stand still - until those boats begin their resonant harmonic. There is no size or type of mono that will escape this - we have watched large commercial ships fall prey.

Those in catamarans stand on deck scratching their heads trying to figure out what the hell is going on with all the monos in a flat-water anchorage.
...
Mark

No harmonics here (12-foot-deep Mildred Island).

[captainfitzwine]

I have logged over 15000 miles on my lagoon 450 since June 2012 and sail whenever possible. But there is a reality that can't be ignored: the shortest distance between two points is a straight line. If I was living in the days of old, I would wait out for the the right wind to blow my way. Sadly I do not have that luxury most of the time. Cats can and do sail well and considering the weight and luxury I'm hauling around do just fine - comfortably!

[Polux]

Originally Posted by captainfitzwine

I have logged over 15000 miles on my lagoon 450 since June 2012 and sail whenever possible. But there is a reality that can't be ignored: the shortest distance between two points is a straight line. If I was living in the days of old, I would wait out for the the right wind to blow my way. Sadly I do not have that luxury most of the time. Cats can and do sail well and considering the weight and luxury I'm hauling around do just fine - comfortably!

Yes the shortest distance but not always shortest time. when that shortest line is directly upwind with waves on most boats the shortest time is not directly against the waves. The Lagoon 450 sails well, except upwind where the performance is not good.

I am curious, how many engine hours for those 15 000 miles, I mean on each engine?

[Palarran]

Originally Posted by Polux

Yes the shortest distance but not always shortest time. when that shortest line is directly upwind with waves on most boats the shortest time is not directly against the waves. The Lagoon 450 sails well, except upwind where the performance is not good.

I am curious, how many engine hours for those 15 000 miles, I mean on each engine?

Wow, good for you - call old fitzy out cuz who believes he's gone 15k miles in 3 years let alone sailed a majority of them. Must be a lot of hours because his boat suck's 50% of the time.

[Polux]

Originally Posted by Palarran

Wow, good for you - call old fitzy out cuz who believes he's gone 15k miles in 3 years let alone sailed a majority of them. Must be a lot of hours because his boat suck's 50% of the time.

50% of the time if he sails upwind or close to the wind 50% of the time, a thing that I doubt. I hope he answers about that question regarding motoring and hours on the engines but I do not understand why you doubt him saying that he had made 15K in three years. I do normally 3.5K each year, only sail for about 4 months a year and cruise all the time (no big ocean passages).

Do you have reasons to doubt him?

[Palarran]

Polux - I was being sarcastic because you're calling out a guy with 10 posts on the forum.

But since your last post, and based on the previous one, can you provide a gps printout of your 3,500 mile cruises (by which I assume you mean "sail") and photo's of your engine hour meter per year so we can verify that. To "sail" all the time and do 3,500 miles per year in 4 months, in the Med, or Motorterranean, I doubt.