Catagory A or B....

[andrewhopkins]

At Yarmouth over the weekend, I saw a Yarmouth 23 on its way out into the Solent

Lovely looking boat and it got a good right up in YM and other magazines with comments like "Full sail in a Force 5 was no issue"

I had a look at their website www.yarmouth23.com and was suprised to see that it was a catagory B yacht.

What is the distinction ? My Bavaria is Cat A but I can't see why its any "safer". Similarly, I'd much prefer to be in a Rustler 36 in a F9 storm than my Bavaria.

Are they meaningless ? I'd still like to know how one boat gets a B and another an A though.....

 

[Boatman]

I think one needs to look at what Cat A means verses Cat B, If I remember correctly Cat A is that the boat can cope (what every that means) with waves in excess of 4meters high and winds in excess of force 8 while Cat B says that the boat can cope with conditions upto but beyond those just mentioned. How they test this I don't know. A number of the BenJenBav 30 something footers are Cat B when they are fitted with a shallow keel and become Cat A with a deep keel, so maybe it's related to the stability curves.

 

[bob_tyler]

As an example a Nauticat 44 is only Cat B whereas a 43 is Cat A. The reason, I understand, is that access from the 44 Deck Saloon to the cockpit is only via the doors opening on to the side decks and not directly to the cockpit. On the 43 it is at the rear of the Saloon.

I would consider both to be equally seaworthy.

 

[Twister_Ken]

Definitions

Category Significant Wave Height Beaufort
A - Ocean Exceeding 4m Exceeding 8
B - Offshore Up to & including 4m Up to & including 8
C - Inshore Up to & including 2m Up to & including 6
D - Sheltered Up to & including 0.5m Up to & including 4
Significant wave height means the average height of the highest 1/3rd of the waves over a given period. Waves of double that height may occasionally be experienced. It is possible for a vessel to have a CE marking in more than one design category provided all requirements for those categories are met.

Plus take a look at http://www.hunterboats.com/rcd.htm
for a builder's comments which seem to imply that boats shorter than 32 foot cannot be cat A

It seems sensible to me applied to the Yarmouth. Most people would probably regard her as a coastal/offshore boat, and not an ocean crosser

 

[tonyleigh]

Re: Definitions

Is there a single site that list cats and yachts or must one look up each on builder's site? URL please if there is a single site.

 

[ianwright]

Re: Definitions

Any idea how a Vertue rates? Or a Twister?

IanW.;-)

Vertue 203, Patience

 

[Twister_Ken]

Re: Definitions

Ian,

I remember finding a formula somewhere for establishing stability, involving beam, draft, displacement, ballast weight, inside leg measurement, etc. Apparently, after doing the sums, if you came up with a number that was over 1.5 you would be safe under all conditions short of a tsunami. Down around 1.2, you started worrying about summer gales. Closer to 1, you were advised to steer around ripples.

So I worked the numbers for the Twister, and they came out in excess of 2! I suspect the Vertue would be the same.

 

[bryantee]

Re: Definitions

have a look at www.sailingindepth.com and down load The serious cruising Yacht by John Pocock

I sail a rival by the way