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post #66 of Old 02-23-2018
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Re: Multihull Popularity and Interesting Designs

Originally Posted by colemj View Post
The reality for even performance cruising catamarans of modest size is that any 20+kt achievements will be few and far between, and likely only because it is being pushed beyond safety. All of the youtube postings are more about singular instantaneous speeds surfing down waves than average speeds, or even regular occurrences.

This is a very, very important point - against what I personally think is a serious misconception by people who have never sailed a cat.

So, Mark, correct me if I'm wrong, but let me lay out why I think this misconception about multihulls and speed can be deadly...

Your exchange above shows a very interesting notion about the kinds of speeds cruising cats "can achieve". As you point out - this is not the kind of speed you'd ever sustain. But more to the point, you really would not want to. It is here that capsize and pitchpole start to become a real possibility. Let's look at an example...

In post #18 above, I linked in a video of a new Lagoon 52 (undoubtedly a cruising cat) in fairly intense gale (F9+). Now, just the thumbnail for this video below shows the immediate problem...this boat is hitting speeds of 27+ knots!

But here is the more critical underlying problem in this scenario...

This is a new boat for this couple. But they seem to be clueless as to the danger they are slipping into. To them, they are "breaking speed records" (back to the exchange in the SN post above.). But in reality, look at what is happening to these bows as they are doing this...

In this sequence that port bow in under water for a full 4 seconds! Just insane.

And now BOTH hulls are digging in.

In the midst of all this you can see the woman with a very concerned look on her face. The guys seem oblivious. Her gut is telling her something - as is mine.

Now, I've personally never sailed a cruising cat. But I have sailed the BFS Flagship FIASCO!

And when I start seeing rooster tails coming off the bows, I slow the hell down. Immediately. Because you only have to go through a pitchpole or two to understand that its not something that you want to do.

This is why, as I've read many times and places, drogues/warps are a very good thing on multihulls. When you're stuffing the bows of a 52' footer, you don't just sit inside and talk about the records your breaking. You put out something to slow you the hell down. Otherwise instead of "breaking records" - you're simply on your way to becoming a statistic.

Mark, smj, PDQ, others who know - what say ye? Are these guys flirting with disaster as much as I think they are?

Last edited by smackdaddy; 04-28-2018 at 09:35 PM.
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