FishyFish Tolman Alaskan Skiff and Boat Building Forums

Could you guys tell me in what class a Jumbo or a GA fits?

Cat A; “Ocean”; wind: exceeding Bf 8, waves: exceeding 4 m
Cat B; “Offshore”; wind: up to, and incl. BF 8, waves: up to, and incl. 4 m
Cat C; “Inshore”; wind: up to, and incl. BF 6, waves: up to, and incl. 2 m
Cat D; “Sheltered Waters”; wind:up to, and incl. BF 4, waves: up to, and incl. 0,3m


8bft = 34-40 kts windspeed
6bft = 22-27 kts windspeed
4m = 13ft waves
2m = 6,5ft waves

I guess Cat B? Not that I have the intention to go out wit 13ft waves  .

Source:  http://www.marinesurveysltd.co.uk/recreational_craft_directive_summary.htm

The Tolman Jumbo and the Great Alaskan are 'Cat C - Inshore' boats, neither being specifically designed for "up to an including significant wave heights of 4 meters".  That doesn't mean that they can't go offshore (100+ miles), but if you DO use them for that, then there are some additional requirements that you need to design into your build.  For example, the water exit requirements that would require more and larger scuppers, and a sealed deck that prevents water ingress into the bottom of the boat, construction designed to shed water off the boat even if a large green wave broke over it, and a pilot house that resists water ingress etc.  In reality, you use the boat like an offshore boat ... but with knowledge and care, e.g. don't go out on a bad weather prediction, and come back in when conditions are changing, AND try to design in water-shedding qualities into the boat.  This is very important on boats with large decks, and easier to accomplish on boats with short decks.

Brian

If I get caught in a blow with 26 knot winds, I be crapping myself!

Well... YOUR boat has pretty good water shedding capability as-is.  Minor improvements that would hedge your bets include a higher sill into the pilot house, more or larger scuppers, and perhaps scuppers on the sides of the cockpit deck ...important in a rolling boat that took on a wave.  They make closeable scuppers for that.

Brian

Quote from: Cannon on July 30, 2016, 08:06:43 AM

If I get caught in a blow with 26 knot winds, I be crapping myself!

Well... YOUR boat has pretty good water shedding capability as-is.  Minor improvements that would hedge your bets include a higher sill into the pilot house, more or larger scuppers, and perhaps scuppers on the sides of the cockpit deck ...important in a rolling boat that took on a wave.  They make closeable scuppers for that.

Brian

I have a set of those scuppers, but the location of the spray rail made them unusable.

Quote from: Cannon on July 30, 2016, 08:06:43 AM

If I get caught in a blow with 26 knot winds, I be crapping myself!

unfortunately the Northsea is famous about sudden and unexpected weather-changes..
The forecast can be clear weather all day .. and whoops there's a storm..

The North Sea certainly is a fickle Mistress as they say, we can go out with sea state slight and as soon as the wind swings round a couple of points or the tide turns it quickly changes to sea state rough, not a problem if your ready for it but lots of trailer sailors get caught out.

Sent from my E5823 using Tapatalk

Just noticed this topic...
I am afraid that compliance to CE requirements is probably a bit more complicated than adding some scuppers...
The category mentioned works as a multiplier inside the formulas that determine several things...
For example when determining the thicknes of the plywood needed for bottom panels or side panels
the value of the multiplier varies according to design category. Values are determined for category A and then the multiplier adjusts the minimum requirement according to the designed environment of the boat.

The values for Design category coefficient (determining the design pressure) are: 
A= 1,00
B= 0,8
C= 0,6
D= 0,4

One big difference bethween categories AB and CD is that for A or B category you cannot use Certification module A. In other words...
The builder cannot self-certify the boat as he can for category C or D.
You have to verify plans and production with the help of the so called notified body... (https://www.eurofins.fi/expertservices/en/services/certification-and-product-approval/ce-certification-of-recreational-craft/)

The CE- logo stands basically for product safety... -plain and simple. Quality is not implied although they often exist in same products. CE is simply a statemend by the manufacturer that the product copmplies with european demands and is safe to use. If something nasty happens, the standards define what the word "safe" means.... (in court). You may not commercially sell a new boat or boating equipment without this CE label. 

There has been years of expert work on the subject to try to define what that means and harmonize a standard in an european and global perspective for boats 5,5m to 24m.
Americans as well as all the major classification experts have been involved in the harmonisation work also and its actually partly based on ABYC rules.
As a result of this expert work there are basically some 70 standards the boat has to comply to...  I remember reading somewhere that ABYC considers boat that comply with the european requirements to be in complieance with their rules also... Because of thie expert work there now is a basis for European common market for boating industry.

The problem with all this is that all the standards cost money, and they are extremely jealous about the standards texts, eventhough they are publicly available to anyone.

Luckily there is a way around most of that...
Finnish working group and notified body have produced instructions for making workboats. The instruction is mostly based on these standards, they differ on the safe side, in a few oints. So now you can have a look at the condensed version for free.

https://cdnmedia.eurofins.com/european-east/media/2847843/guidelines-for-commercial-craft-version-20162.pdf

The coordinating group: http://www.rsg.be 



PS.  I am currently studying these standards... so if there is interest...
PPS. I am planning to produce the required technical documentation for a CE-sertifiable version of the Tolman series