Unbearable slamming

[Wellington]

Originally Posted by svBeBe
Whichever cat you choose, try to sail it offshore in rough seas before buying it. Most frequent complaint from those we have met (all having sailed at least 7000 NM in their cat -- various brands) is that the hull water noise on long passages is almost unbearable.
Judy
S/V BeBe

Originally Posted by Adaero

We chartered an almost brand new Voyage 440+ in the BVI in November last year. [...] the bridgedeck slamming in mildly choppy water was terrible and on occasions would jar your whole body, on one rough day it was unbearable. Personally I couldn't travel any large distances with the amount of slamming we encountered at all points of sail.

Originally Posted by Adaero

Adaero

I'm surprised hull water noise is not more often discussed on this forum. The quotes above reflect my concerns. "Unbearable", that's also the word I used in a different thread to describe how we felt about slamming on a Leopard 42, that we chartered in Tonga last month. We were then sailing with whales metres from the boat, so there was plenty of excitement on board, we shouldn't have paid so much notice to pounding. And no, the pounding wasn't caused by disoriented humpback whales hitting our hulls... I can only imagine what it must be like during passages, without much to distract you from pounding and slamming for days on end.

This charter in the protected waters of Vava'u further convinced me that bridge deck clearance should be the number one parameter when it comes to choosing a bluewater cat. In particular, it surprises me that Leopards still make it on the shortlist of many of you for bluewater cruising, for that reason alone. Don't take me wrong: we liked this cat, who is comfortable and well adapted to charter in calm waters, and faster than I thought (we hit 13 knots). Beyond bridge deck clearance, it seems that the shape of the hull plays a big role. In particular, in spite of low bridge-deck clearance, the Lagoon 420 (maybe also because of its weight) seems to be surprisingly comfortable, even in gale conditions (see in particular the posts by "Octopus")

At the moment, the Fountaine Pajots top our wish-list: a lot of buoyancy at the front, and a very high bridge-deck clearance. For instance, thanks to its hull design, the FP Bahia 46 seems to be, from what I've read on this site and others, one of the most comfortable and easy cats on the market (second-hand market now). We tried both Lavezzi (Jan 2008) and Orana (June 2008), on calm seas and 10-15 knots of wind, so we couldn't get an idea of how they would fare as far as slamming is concerned.

Thanks for your feedback.

[shadow]

This is good to know as we were in the CAT market for a while now but we've moved on to monos for the most part.. Keep us informed though.. cheers

[rebel heart]

I had a light displacement monohull Ericson that used to make a lot of noise; really loud in weather. Our current tank-boat doesn't sound the same at all; much quieter.

[shadow]

That brings up another related question Rebel, I thought that most mono's cut through the waves and not slammed on them (depending on hull desdign). I knew that cats had that "burping" effect. I just thought that the usual noises for a mono were the twists and creeking of the hull, etc.. but not actual wave slapping..

I'm talking about sailing monos not motor as the ones I've been on were going very fast and planing nicely..

[rebel heart]

You can get a lot of slap on the sugar scoop sterns of mono hulls. I've got a canoe stern, so I don't hear much of that. A light boat, no matter how you slice it, will bob around a lot more in the water and have a more agitated motion, which yields to having more wave slap action. A lighter boat probably has a thinner hull as well, so the noise will transmit easier.

[roblanford]

Originally Posted by rebel heart

You can get a lot of slap on the sugar scoop sterns of mono hulls. I've got a canoe stern, so I don't hear much of that. A light boat, no matter how you slice it, will bob around a lot more in the water and have a more agitated motion, which yields to having more wave slap action. A lighter boat probably has a thinner hull as well, so the noise will transmit easier.

Hey rebel, I sure like the Hans Christians. I like the '49 Studebaker Champions too. You can't tell on either one which way they are supposed to be going, looking the same on both ends. Maybe if you mounted a rudder on the front of your boat you could have a one hulled proa and shunt instead of mushing through a tack. Can HCs tack or do you have to wear off to work to weather?

[roblanford]

I think that unbearable slamming is preferable to unbearable sinking.

[Adaero]

Originally Posted by Wellington

In particular, it surprises me that Leopards still make it on the shortlist of many of you for bluewater cruising, for that reason alone. Don't take me wrong: we liked this cat, who is comfortable and well adapted to charter in calm waters, and faster than I thought (we hit 13 knots).

The Leopard 42 is a lot different to the latest 40 and 46. They are Melvin & Morelli designed not Simonis (sp). I really liked the Simonis designed boats and when I was at the factory last week nearly all I talked to preferred the design of the old 43 and 47 over the M&M boats.
One improvement on the 40 & 46 is the bridgedeck clearance. My 46 fully loaded including water, fuel and cruising gear still has 750mm (34") clearance under the bridgedeck. My quote stated above was from the BVI last year, the week before I was on a L46 and it didn't slam once so I am confident that even offshore any slamming should be minimal.
I leave Cape Town in around 3 weeks time for the 5500 mile trip to Tenerife and I will be posting my report of the trip on my blog if anyone is interested. If it slams, or performance is poor, or anything breaks you will all get to know about it.

[Jeannius]

Good luck with the trip Andy. I know what it is like going through the decision making process and then a long build lead time but, once you are out there, you'll have a great time.

[freetime]

Originally Posted by Adaero

The Leopard 42 is a lot different to the latest 40 and 46. They are Melvin & Morelli designed not Simonis (sp). I really liked the Simonis designed boats and when I was at the factory last week nearly all I talked to preferred the design of the old 43 and 47 over the M&M boats.
One improvement on the 40 & 46 is the bridgedeck clearance. My 46 fully loaded including water, fuel and cruising gear still has 750mm (34") clearance under the bridgedeck. My quote stated above was from the BVI last year, the week before I was on a L46 and it didn't slam once so I am confident that even offshore any slamming should be minimal.
I leave Cape Town in around 3 weeks time for the 5500 mile trip to Tenerife and I will be posting my report of the trip on my blog if anyone is interested. If it slams, or performance is poor, or anything breaks you will all get to know about it.

Beautiful! I can´t find your blog.... Good Luck.

Do you have the weight of the boat, from the crane at the pic?

[trinescape]

our tri which is 36 ft has a bridge deck clearance of 700 mm and yes when the waves get bigger we some times experience '' slamming'' i find that it happens more when in a confused sea way it has never really bothered me because its not a regular occurrence but i cannot imagine being on an extended cruse hearing thump thump every time you go through a wave what is it an extremely overloaded cat or just plain bad design?
andy

[Adaero]

Originally Posted by Jeannius

Good luck with the trip Andy. I know what it is like going through the decision making process and then a long build lead time but, once you are out there, you'll have a great time.

Thanks Mike, and thanks for your input and help during the process.

Freetime,
I don't have the weight from the crane but I do have the weight of the boat an hour beforehand as they put it on calibrated load pads for me. If someone wants to start a sweepstake on another thread I will reveal all after the delivery trip as well as performance figures!!

Unfortunately the server with my website on has temporarily crashed but should be up and running again properly next week.
www.tulliana.adaero.co.uk

[ireaney]

Hi Andy
Looking forward to the blog and congratulations, I am sure you will be more than delighted with her, all the best on your trip.
Cheers
Ian

[yeloya]

We tried both Lavezzi (Jan 2008) and Orana (June 2008), on calm seas and 10-15 knots of wind, so we couldn't get an idea of how they would fare as far as slamming is concerned.

Thanks for your feedback.[/quote]


I believe this is relative, ie. the slamming of cat X could be much bigger than Cat Y and the owner coulşd still live with it very well..

As you said that you tried Orana in calm seas, I've been sailing it from Palermo to Marmaris five days and nights without stop, in different conditions from nothing up to 33 Knts of wind (mostly from aft), with following seas mostly up to 2-3 meters, never experienced excessive slamming. I could sleep like a baby.. But again, for some people, this could be described as "excessive".
However, if for someone, slamming is a concern, be carefull with the Orana.. The protrutation under the bridge on the owners side's fantastic queens bed and just under yr pillow, is slamming more than anywhere else and this could be an issue..

Just wonder, how could you define "unbearable" ? Wouldn't this be different for everyone ??

Yeloya

[imagine2frolic]

Slamming is a trait of a cat. Some do it worse than others. Just like some monos are much more tender than others.

When I first started travelling on my cat. I had only day sailed on large cats, and never experienced slamming. When we got into our first snotty weather it was very unnerving. I learned to make adjustments with the boat to reduce, or be rid of the noise. After 10k miles I have become use to it when it is there. I still don't like it, but it is part of sailing a cat.