Tuesday, June 24, 2008

Wave Slap on a Catamaran

I recently posted a question on an active yahoo live aboard community group called Captain’s & Admiral’s Café. As a subscriber to this very active group I was receiving lots of posts but none were on the topic of cruising Catamarans. So I asked for some Catamaran related experiences from the members and I received several opinions.

The 1st advice I read was to go to the Toast Floats. I read “That which doesn’t kill us” and loved it. Although it talks about things that break I am jealous and I can’t wait to be that person fixing that which is broken. It appears there is much more to read and learn from this family living aboard their Lagoon 380 catamaran named Don Quixote. The blog contributor describes his cat as a slow starter houseboat. Check it out.

Someone also mentioned TeamHudson and their excellent adventure. So far I have just skimmed this blog, but from what I can tell he is just like me only quite a few steps ahead. He began his blog before buying his cat and is now living on his cat with his family. Again, I am jealous and inspired to keep dreaming and to find a way to make this dream a reality. His blog covers many topics from Environment, fishing, moving aboard, financing and sharks to list a few.

The one comment that stood out as a possible deal breaker was the issue of Wave Slap. It started with some comments about a Catana owner that complained of wave slap on a recent passage. Wave slap is what occurs when heading into steep waves and is more prevalent on cats with low bridge deck clearance. The wave crashes underneath the bridge deck and can make for some uncomfortable passage making. See the photo of the Catana shown to the right. The bridge deck clearance is good in some places but not all, so perhaps the design although maximizing interior space, contributes to wave slap. There is no doubt wave slap is a concern, but so is healing over at a 45% angle in a monohull.

I was concerned and was happy to hear from the owner of a Fountaine Pajot Athena 38. His thoughts were just what I needed to hear and as I expected. His thought was “All designs have their unique design effects” and that wave slap is an issue and just that. With over 2000 miles on his boat he claims only 200 or so were miles that may have included some wave slap. He mentioned one trip that was particularly bad. “Slogging into 8ft swells sucked and was noisy with the slap issue “ but he also said there aren’t many boats that would have been any more fun in those conditions. He also said if needed the boat was doing fine and he could have kept going, but instead changed course to resolve the issue. He still prefers his Cat and said “All and all the positives far out weigh the negatives for my family.”.

Another family chimed in that switched from a Morgan 41 classic to a Manta 42 Mk IV and said there are ups and downs, but they are very happy with the switch.

"We’ve had no problem at all getting used to our new huge salon, cockpit, washer/dryer, water maker, genset… the list goes on and on."


They did bring up some important information surround rig fatigue.

"Since cats don’t heel the standing rigging is tensioned far more often than a mono hull so rigging needs to be replaced way more often. Most experts I know say 5 years max. The good thing is that we have a lot less wire so it only costs about $1500.".

They are happy with their Manta and recommended them as a great company to deal with.

4 comments:

Jim and Heather on Meerkat said...

We have an Ocean 49, which is basically a bigger version of the Manta - stretched hulls, but the same rounded underside. We tend to get less wave slap than the Catanas, as they have that sharp "step" on their undersides. Your two pictures show this perfectly. Our suggestion is to find a smooth underside without any sharp angles. Works for us so far...

Mike Harris said...

Just found your blog, Dave - thanks much for your efforts. I, too, am beginning to "chase the dream", though a bit late. I've sailed monohulls all my life but at 74 I need to twin-hull stability. I hope to find the "right" Cat to sail among the 7,000+ islands of the Philippine archipelago - Right meaning the right price and condition. Now I know you're looking for much the same thing I'll be very interested in following your blog. Thanks again.

Toast said...

Two corrections, Dave. Don Quixote is the name of our boat, and both blogs -- The Excellent Adventure and Toast Floats -- are written by the feminine half of the co-captain couple. One thing I find a lot more frequently in the catamaran world are very active, non-dragged aboard female partners. If you have a spouse, this is a big consideration, IMHO.

BenjaminFranklin said...

I'm an old yachtie, and I made my first ocean crossing in 1971. I also finished out a mono and sailed it across the Pacific in the 70s. I designed a big catamaran and have started to build it. (Summer of 2008) I hate wave slap, and have no berth 'shelves' under my bridgedeck. Kanter wrote an article on the subject, and you can find a link to it on my website at:
http://www.dunnanddunnrealtors.com/Catamaran.html

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