Perceived Sea State and Freak Waves.

[John Kennett]

Originally posted by toby.budd
How many of those who post on this site would be happy to go out to sea and flood their boat and be confident that there systems would continue to function and get them home

In a RIB, yes. If you're not confident about this, then don't go far in your RIB -- a green wave getting into the boat with you will fill it up very quickly!

We had this in Phoenix, off Cape Wrath a few years ago. We didn't stuff the boat as such, a big steep wave just fell on us. It knocked the windscreen off, inflated a couple of lifejackets, and filled the boat to the top of the tubes. Time went very slowly while about 2 tons of water drained out through a couple of 2" scuppers, but it didn't really take all that long. Just kept into wind and steadily motored forward, although having the torque of a diesel probably helped at this stage.

All I could think of was Alan's parting advice as I left Dunstaffnage that morning: "You should be OK without an air filter, but try not to get too much water in the boat"!

As for filling a RIB with water making it less stable, this is clearly not so -- load up a RIB and see if it wobbles more, or less. Never mind calculations and formulae for CoG, CoB, FSE, ABC, TCP or whatever!

John

[Mike Garside]

Originally posted by Alan Priddy
Mike, I am not 100% sure of this but did Magalen Alpha have some sort of keel and how heavy was it?

Sure, Alan, 2.5 tons of lead bulb at the end of a 15ft carbon fibre blade. But it also had a 76 foot mast supporting a monster main sail and head sail. Take away the keel, the mast and the sails and the hull has excellent form stability. Similar to a RIB.

I've continued to read the rest of the posts on this thread with great interest. And I'll continue to ponder. I had never considered flooding my boat but this now is another option to add to the theory of my heavy weather repertoire.

I hope it will remain theory rather than practice for me as I would also have to flood the cabin as well as the rest of the boat. The door only has a 6 inch high sill. Furthermore the boat builder obviously did not consider this as an option as he installed the electrical control panel at knee height.

And filling the RIB to the level of the top of the tubes will definitely flood the engine box, too. The breather holes are below the level of the top of the tubes as well.

[Charles]

Very interesting thread indeed. I would just like to point out that I very much doubt that anyone would find themselves in seas necessitating this action. The last thing anyone should do is to flood their rib off the shingles bank when you have a severe wind against tide situation - what Alan P, Mike and a few others are referring to are open sea, SEVERE 20+ foot cresting wave conditions. I have found myself in a flooded rib (by accident) and I can tell you it is not much fun. The rib was surprisingly stable with the waves simply washing over the tubes and proceeding out the other side. No problem there.
This should be a last resort situation I would imagine??

[John Kennett]

Charles is absolutely right. As a guide, let's say if you're within 200 miles of land, don't consider this as an option.

Please, I don't want to read a rescue report from Solent Coastguard where someone decided to flood their RIB "because they read about in on the internet"!

For all but the most extreme RIB cruisers this should be seen as a purely hypothetical discussion. On the other hand, it is good to know that your chosen type of boat will still float when it's full of water . . .

John

[Manos]

As far as I know most RIBs over 5.50 mtrs are flood tested in order to pass the CE standard and to get to the off-shore category (I think is B or A) otherwise they are only fint for coastal use.
The Falcon 700 RSR was a support RIB for VOLVO PENTA during last years transantalntic race and that was flood tested. It had 4 tonnes of water in it and it took 4 minutes to empty it.
The 5.65 and the 6.50 are also in the off-shore category and they are flood tested.
Gemini the same, Cobra and Scorpion the same and also many others.

[Manos]

If any one is interested about wind speed and wave hights have a look at this site

http://marine.cwb.gov.tw/CWBMMC/windwaveE.html

[Manos]

We encountered some VERY BAD weather

[Manos]

like 'when I was a reach man' Same tune!! LOLOL

[Manos]

and where is it going??

[gaelforce]

great thread. There's a lot to be said for checking the weather forecast.