Under What Conditions.....

[scarlet]

Whenever I've been sailing on a catamaran, and the waves start to crash over the bow, I start to get a little scared about the boat flipping stern over bow (pitch poling, right?). I don't have this fear on monohulls because the deep heavy keel. But catamarans are so light... I think I get scared because I don't know enough about how much the cats can handle before flipping.

Can someone educate me on this? Is it virtually impossible (like on a monohull?) or is there a certain wave height that would cause this? Or is it when waves come up over half the cat? or maybe a specific angle? Does anyone have a recollection of this ever happening to a catamaran? perhaps an article?

[Kalimniosjohn]

I could be very wrong, but I think I read somewhere that you need very large waves to cause a boat to pitch pole. Something like the waves heights need to be 75% of boat length. 40 foot boat = 30 foot waves.

[boom23]

I do not have numbers for you but I've been in some very nasty storms of New Zealand and the S. Pacific islands while on my Lagoon 450.

The whole trick is to control the boat speed. If the bow goes under and the sail has enough power to push the boat over, you are in trouble... So, reduce speed, hit the waves at around 45 degrees and you should be fine (not comfortable, just fine).

You also have to be extra careful just in case something breaks. If that happens, all bets are off. I was very conservative. During major bad seas, my target speed was 5-6 knots. You have to figure out a safe speed for your boat.

I'm sure others will give you more technical information.

[billknny]

Originally Posted by scarlet

Whenever I've been sailing on a catamaran, and the waves start to crash over the bow, I start to get a little scared about the boat flipping stern over bow (pitch poling, right?). I don't have this fear on monohulls because the deep heavy keel. But catamarans are so light... I think I get scared because I don't know enough about how much the cats can handle before flipping.

Can someone educate me on this? Is it virtually impossible (like on a monohull?) or is there a certain wave height that would cause this? Or is it when waves come up over half the cat? or maybe a specific angle? Does anyone have a recollection of this ever happening to a catamaran? perhaps an article?

Some comments...

First is that monohulls can most certainly pitchpole--under the right conditions, of course some of them will right themselves afterwards.

Second, waves crashing over the bow do not cause pitchpoling. Surfing at high speeds down a wave, and then burying the bow in the back of the next wave is the cause. When the bow suddenly stops, and the back of the boat keeps going, that's a pitchpole.

[Cheechako]

I seldom had any waves over the bow in a 42 ft cat. Are you talking small cats, like Hobie's at high speed? or...? I did experience "slamming" under the bridgedeck. I wouldn't worry about pitchpoling in a large cat except in storm or very large seas.

The thing about cats is this: They seem stable and sailing mostly flat, even when over stressed, until suddenly, they go over. You get little warning.
I remember being caught in a sudden 40-45 windspeed with higher gusts and full sail up. My cat hardly heeled at all. I'm looking at the anemometer and thinking "really? I can't even tell the winds that high". Then with the help of a 6-8 ft steep wave it heeled fast. Fortunately, I was just about to dump the mainsail anyway at the time this occurred.

[44'cruisingcat]

Originally Posted by scarlet

Whenever I've been sailing on a catamaran, and the waves start to crash over the bow, I start to get a little scared about the boat flipping stern over bow (pitch poling, right?). I don't have this fear on monohulls because the deep heavy keel. But catamarans are so light... I think I get scared because I don't know enough about how much the cats can handle before flipping.

Can someone educate me on this? Is it virtually impossible (like on a monohull?) or is there a certain wave height that would cause this? Or is it when waves come up over half the cat? or maybe a specific angle? Does anyone have a recollection of this ever happening to a catamaran? perhaps an article?

You've been spending too much time reading the alarmist nonsense on this forum.

You can pitchpole any boat, but the bigger the boat, the less likely. For a large cruising cat it would take extreme conditions.

To give an example, a crew racing on a ShawnArber high performance cat in a Brisbane to Gladstone race were sailing in 30 - 35 knots downwind with full main and a spinnaker, frequently reaching speeds over 25 knots.

They still didn't pitchpole, although they did bury the bows a few times, before eventually deciding to reef the main.

Cruisers in those conditions would have no main up, and maybe half a headsail. In a much lower powered boat.

And these days, many production catamarans are anything but light. Some are considerably heavier than many similar length monohulls. Not that that makes them any safer....

[sailjumanji]

Seawind 1000 (33 ft long cat), 150 mile long offshore race, 32 knots true wind, loose beat, double reefed main, 13-15 knots boat speed. Punching into waves that washed over the windows of the hard top, dumped into cockpit behind us, and drained. When the front windows went opaque with green water, you stepped forward under targa to avoid water dumping down collar of your fowl weather jacket. Everyone on the boat was seasick, including the two of us that took meds. The mast pumped a lot. The boat would decelerate a bit when we punched waves. But never, ever close to pitch pole. Biggest risk to me was dismasting. First place, Multihull C (big cat) division!

A Bahia 46 crossed the finish line about 15 minutes ahead of us. (They owed us a couple hours on time correction). At the marina, they parked in front of us, pulled out the water hose, and started washng the barf off of their stern!

In that race, about one-third of the monohull fleet dropped out, for those of you that think they fared better!