Wave Size

hoffer · 24 April 2002, 20:57

Have Just bought a 6m Nouva Jolly Rib with 100hp engine. Have it in Dun Laoghaire, Dublin. Wondering what size waves/Swells can a boat of this size handle. Mainly bought it for Skiing

Keith Hart · 25 April 2002, 06:00

Hi Hoffer

Take a look at the transom and you may find a plate which has details of the boat (a bit like the plate in the engine compartment of a car). This should have the class of boat on it. This is the official guide but as people on this forum will tell you it is only a very rough guide.

The categories are (simplified version):

A - Ocean. Extended voyages where wind conditions may exceed force 8 and significant wave heights up to 4m.

B - Offshore. Offshore voyages, wind conditions up to force 8, significant wave heights up to 4m.

C - Inshore. Coastal waters, large bays, estuaries, lakes and rivers, wind conditions up to and including force 6, wave heights up to and including 2m.

D - Sheltered Waters. Small lakes, rivers and canals, wind conditions up to and including force 4, significant wave heights up to 0.5m.

Bear in mind that my Quicksilver 3.4m SIB is certified as category C, I can tell you that it would be a bit hairy, to say the least, in a force 6!

Take a look here for exactly what the conditions are at the various wind speeds: http://www.seathree.demon.co.uk/seastate/index.htm

However it has been said that a good RIB or SIB can take far more punishment than the crew can!

Best of luck and keep on posting.

Keith Hart

hoffer · 25 April 2002, 10:17

Keith

Thanks it's a cat. B,

Hoffer

Alan · 25 April 2002, 10:28

but would you really be confident in it in wave heights of 4m and in a Force 8? The RCD is a bit of a joke really so I wouldn't put that much store by it. Basically your boat will probably stand up to the conditions longer than the crew. Unless you are particularly masochistic I'd say anything upto a F4 is fun. F5 is a bit scarey and F6 is time to be in the pub!

hoffer · 25 April 2002, 10:34

Went Out Yesterday, 2M waves looked too big for me, but give it time, and experience !!!

dimitris · 25 April 2002, 10:42

Hi All,

What Keith is refering to, is probaly CE Categories.

Be careful though, the Italians have their own certfication authority for CE categories (as far as I know).

As a result an Italian CE B Class maps to a C Class according to EC standards.

If you consider your boat as a C class , then it maps exactly to what Alan said .

Having myself a 5m CE C Class RIB, I would totally agree with Alan.

Dimitris

GraemeCooper · 25 April 2002, 16:13

Hi Hoffer

As Keith and the others have rightly said, it is more the crew than the boat you have to worry about.

The ratings in modern RIBs are pretty useless really - as it is not even as simple as saying a 4 metre sea would be OK for one and not fo another - a lot depends on course / wind / position that just saying Force whatever makes no sense.

I have been out at sea in a 14 foot Gemini Infltable - with solid wood floor but no inflatable keel - in a Force 7 - 8 and HUGE seas with little difficulty - and at other times have been in an 8 metre RIB in a 6 and felt decidedly uncomfortable.

As in most things you need to use your judgement- and be honest about your own capabilities.

Also, try not to adopt the Power Boaters attitude of 'Gung Ho' on your course to steer no matter what the conditions. If it is too uncomfortable - use the sailing techniques and tack your course to make things easier.

Happy Ribbing !

Keith Hart · 25 April 2002, 16:30

I've just browsed through the thread 'Inshore', ( http://rib.net/forum/showthread.php?...hlight=inshore ) it's worth you taking a look Hoffer.

As Brian said:

Basically if you feel REALLY nervous and apprehensive-go home. If you feel frightened it's too late!

Keith (still retaining the formality of a surname) Hart

sirzap · 25 April 2002, 16:56

Beside all the good points already made...a ribs ability to cope with large seas depend on the skill and experience of the Coxswain and crew...even a large rib can get into trouble with an inexperienced crew.

mccabe · 25 April 2002, 19:01

Hi Hoffer,
I found a trip back from Aran Islands to Galway in a force 5-6 in
my 5m with a 50hp hairy enough but I prefer not to look for trouble.Make sure that you have flares, Vhf anchors 2 types as breakdown in bad conditions is even worse!
Happy ribbing.

Garygee · 27 April 2002, 11:32

Hi Hoffer

Be very carrful using a plate rating to decide what your boat is capable of, either way.

Part of the rating is what equipment is carried as well as the catagory of boat and there can be some extream swings each way.
Keiths table is spot on, but my Ribcraft 4.8 is Cat D,

D - Sheltered Waters. Small lakes, rivers and canals, wind conditions up to and including force 4, significant wave heights up to 0.5m.

Tell this to the RB4 people !!.

Also wave height for the B & A often refer to open ocean wave height, which often roll and seldom break until it get very windy.
A 4M rolling wave may be no prob, but if its breaking in shallow water, that may be a major problem.

Keep the plate rating in the back of your mind and start of easy and decide what YOU, YOUR CREW can handle then think about the boat, bet the boat wins.
Also check if the equipment is still there for Cat B, not sure but I think things like 406MHz EPIRB, Liferaft etc are requirements.
Maybe someone knows what the actual equipment requirements are.

It is better to decide to give today a miss and play tomorrow rather than think the boat can take it and never play again !!

Regards Gary