What would take to flip a rib

[smokie]

Outside of doing something really careless, what kind of seas, conditions, would it take to flip a 6m rib? I'm not the type that is going to go flying off the top of swells at full bore. Mainly fishing offshore in northern California where unexpected conditions can get nasty.

[pettal]

As far as I know and am ready to be proved wrong.....but!

It's very hard to tip a rib up sideways even if it's been dragged down the face of a wave.

So the only way that I know how and have seen it done is going off the top of a big steep wave at medium to high speed into a howling head on wind and getting the wind to catch the underside of the rib and tip it. Teckernirkel term would be to pitch pole.

I think the only other way would be with a following sea and to bury the nose into a trough with a big wave coming up from behind.....maybe!?

[Seb]

There are loads of factors that could lead to the capsizing of a RIB:

Running into a steep head sea without powering off will make a boat take off at the crest. One big gust of wind under the hull at this point and the boat is likely to go head over heals.

Loosing power and drifting beam on to large breaking seas.

Rogue waves (they do exist)!

Whirlpools.

Rediculously large seas of any kind that a RIB cannot cope with.

Unsuitable RIB for the conditions (rigging, hull form etc).

Burrying the bow and skewing around broadside on to the sea before regaining headway.

etc etc etc.....

However, being out in conditions that are likely to capsize you are generally rare and a well equipped boat with a sensible and skilled skipper will generally be able to cope with some pretty harsh conditions and more to the point, will know their limitations and when to run.

Of course, lifeboats often have no choice in the matter and the same goes for people like AP who may be miles from a safe haven!

[Zippy]

Before i bought my rib i was fortunate enough to be out in Brighton for the weekend of the Powerboat P1 racing. anyone who was there will know it was pretty windy and rough.

Being new to ribs at the time i was amazed at how safe the boat felt no matter what we were doing. i know my nerve would have gone way before the boat had any problems out there that day and thats what made me choose a rib over anything else.

As people have said here. skill of the skipper is very important and as with anything theres a large portion of common sense involved in any form of boating.

[ADS]

I don't know whether this has been posted on here before but it shows a lifeboat atlantic 21/75 flipping, unfortunatly its in quicktime:

http://myweb.tiscali.co.uk/whitslb/video.mov





It is suprisingly easy to roll a rib if you end up beam on to a rough sea, I rolled a little Ribcraft, while performing a dinghy rescue.



Alex

[Zippy]

That video is amazing!

And to think the crews do that for no other reason than to help others in distress!

i take my had off to each and everyone of them!

[Nasher]

In my younger days 20 years ago, when my brother and myself would tear about in my dads Flatacraft force4 with far to big an engine on the back we managed to do it both ways.

We rolled it over doing too tighter turns when we hit the wake of another boat, and flipped it over backwards when we jumped off a wave into the wind. The wind got under the bow lifted and stopped it dead, whilst the weight of the engine rotated the stern underneath it.

Rolling was very scary but happened so quickly, and flipping over backwards seamed to happen in slow motion.
If I had to choose I'd go over backwards, you've more chance to brace for the boat landing on top of you.

On both occasions we lost the windscreen but righted the boat quickly and managed to restart the engine.

To those that may consider joining me at sea, may I say how much I've calmed down with the benifit of age.

Nasher

[ollyit]

Originally Posted by ADS

I don't know whether this has been posted on here before but it shows a lifeboat atlantic 21/75 flipping, unfortunatly its in quicktime:

http://myweb.tiscali.co.uk/whitslb/video.mov





It is suprisingly easy to roll a rib if you end up beam on to a rough sea, I rolled a little Ribcraft, while performing a dinghy rescue.



Alex

JEEEEESSAZZZ!!

[Andy]

Seen it happen when a RIB got side on in surf. They where trying to recover up a beach (broadhaven) onto a trailer and lost it on the approach. It was a mess.

Flipping is easy. All you need is too much speed, the wrong angle off a wave and a bit of wind and you are gone.

[slimtim]

Nasher how did you flip her back over? Deflate one side and then try?

I've had a few near misses in my little flatacraft. Last summer i was going into a force 5-6 head wind and it was wind against tide with big solent rollers (huge for my little boat) off yarmouth. I had to lean right forward at the top of every wave to stop the wind picking her up. I could feel it rising every time I reached the crest! I was coming back from a photo shoot too so wasn't in a hurry to jump in the drink with all my camera kit

Tim

[keytouch]

How do you possibly right an upturned rib?

[Andy]

Unless you have a self righing system installed I think you would find it impossible to turn it back over unless you have some major help from other boats. Or if your rib is very small you can right using ropes and standing on the upturned hull, lean back etc like righting a small dingy... but its very hard work.

[Nasher]

The Flatacraft was easy for two to turn back over. We did it the way we were taught on the BSAC boat handlers course which was aimed at Inflatables back then.

Tie the painter (Bowline) to one of the handles on the side, throw it over the hull, then put your feet on the opposite tube and haul yourself up the rope. For the second time that day the boat lands on top of you. In reality you get right out of the water and lean out holding on to the rope. Its easier with two people, you tie painter to the side handle leaving both ends long enough to go over the hull

The Flatacraft Force 4 is only 4 metres, I wouldn't want to try it with anything bigger.

Nasher.

[Rogue Wave]

do you think you could right them easier if you deflated the side that the boat is pivoting on, I dunno, just asking

[Turbodiesel]

I have turned many ribs over on purpose!, its great fun!!. We do it to test the PIRS (post imersion restart system) on the engines. I have some pictures of it being done and then recovered, but for some reason i cant seem to be able to put them up on the web site.

[Bilge Rat]

Ok i'm going to dispell all the myths about how easy it is to flip a rib.

last September we were launching my boat off a shingly beach at Whistable, we use a tractor to launch and recover and have done it lots of times, so we pretty much know what we are doing, on the day we attempted to launch the wind was on shore, it was almost high tide and then was a small swell approx 2 foot dumping on the beach at intervals, i made the desicion that we'd go from the beach as we'd launched like this many times before with no problems, so the driver backed the boat down into the sea and whats supposed to happen at this point is we wait for a low spot, slip the boat off and the crew hold on while the driver jumps on, lowers the engine and away we go, all normally takes about 30 seconds...... however this time the boat slid of the trailer, at the same time a large wave dumped on the back deck swamping it completely and started to spin the boat broad side to the beach, two of us and the tractor driver desperately fought to keep the boat straight but to no avail, the next wave lifted the now side ways on boat up and flipped it over the top of us throwing my crew man onto the beach and pinning me underneath between the seat back and the beach with my head underwater, as the wave fell back i was able to shift my weight sideways and shuffle into the crawl space at the back, the next wave hit and rolled the boat slightly to one side, i saw a shaft of light and went for it and squeezed through as quickly as i could.
Once on the beach in blind panick myself and my crewman grabbed the upside down boat and literally flipped it back up the right way, the tractor driver had started to move as he'd seen what we'd done and quickly backed the trailor into position, we turned the boat and let the next wave ram it nose first up the beach, then attached the winch and literally winched it back up onto the trailer.

Its that easy, a few mis calculations and not reading the signs right and we were now in a who world of pain, luckily my mechanical genius was close by and spent a few hours running, drying and checking over the engine for me, the tubes and hull hadn't sustained any damage at all, i lost a few bits not adequately tied down on the deck and suffered a broken rib and some nasty bruieses for a while.

So what did i learn from this..... Well in this case the A frame definately saved my life, had it not been there i'd have been crushed into the beach harder and wouldn't have been able to squeeze out, the A frame also saved the engine as it was still up in the transit position at the time, the A frame stopped it hitting the beach. Walking back down the beach at low tide it was plainly obvious what had happened, small short dumpy waves hitting a fairly steep beach coupled with the on shore wind had created a nasty situation. This time i'd been lucky, an engine service, some new oil and plugs and a good clean out and the engine is as good as new, the fact it hadn't been running or lowered had saved it being damaged, quick reactions and having my mechanical friend close to hand also prevented further damage.

Now i'll only launch from a slip way into a harbour

[Swifty]

A cautionary tale of what can go go wrong, will go wrong. Classic Sods law.

Ratty's tale should be heeded and respected. Sure there are some who will critiscise judgement and forethought, but he was out doing it, and can now pass on the warning. This is what the site is all about, exchange of ideas and experiences.

I would like to point out another hazard following inversion, and thats the boat sticking itself to the water like a sucker. As the boat is lifted on a swell the air trapped in the cockpit is pushed out via the elephant trunk, and then closes to prevent anything going back up, after all thats what its for, but there is now no air gap in the cockpit and to right the boat will require a lift of several tonnes to break the air gap or to let air into the void by another means.

I have concidered this dilemma when writing a risk assesment. And am open to other ideas, but I thought of having a 18" length of 1" plastic hose which could be pushed or pulled into the trunk to open it up, allowing air into the void, and making righting much easier.

Also how low can one deflate a tube thats underwater, has anyone tried it?


Tim.

[Bilge Rat]

Thanks Tim,
Lets image a scenario where your likely to flip a boat at sea, my situation was a unique catastrophic sequence of events happening on a beach, but had i been at sea then it would have been a different matter. It's pretty unlikely that your going to flip the boat on a flat calm sea, even jumping wake is unlikely to cause a capsize unless your really trying, so with this in mind its more than likely to happen when its really rough, so what would the chances of righting the boat be in these conditions and without an inflation bag ?then if you did manage to turn it over what would good would it do you, the boat would be flooded and you'd have no means of propultion and subject to a heavy sea.

What i've learnt and thought about since my experience is A how fast it can go and B what do you do once its gone, at the time my flares and hand held radio were safely stowed in the consol locker and would have been out of reach had it capsized at sea, both of us were wearing the correct safety kit and both had manual inflating gas life jackets which would have prevented us being trapped if it had gone over at sea, the anchor, warp and chain fell out and i lost a few bits of rope which wern't really tied in properly.

[Swifty]

This is why we are doing the risk assesment. The scenario dictates at the very least you are going to need to alert the emergency services (assuming you are alone) as to your situation. Problem is as you say the onboard vhf is under water and the hand held is in the waterproof bottle under the seat.

I have never experienced an inversion in a powered boat but would treat the righting as a catamaran sailor would.

1) swear
2) check crew
3) swear and pass the blame
4) rig a hand hold
5) stand or sit on the leeward side and lean out
6) swear
7) prepare to be bashed as the boat rights
8) swear
9) swear
10) climb aboard and assess problems
11) swear

I did an experiment quite a few years ago where we let all the tubes down in a Avon 3.0M RIB. We could sink the stern but not the bow, and not once did it try and capsize.

[pettal]

Bilge Rat: Glad to hear that you escaped relatively unharmed! It's a scary prospect being caught under the water, pinned down and running out of lung power.

A couple of points.

It's interesting that you say the A-Frame actually saved your life as we tend to look at A-frames as a convenient method of holding nav lights, rader, aerial.......and not generally a piece of prime safety equipment, but what you say makes perfect sense in that particular situation....I shall look at A-frames in a new light! Maybe they should be fitted as standard with this in mind?

My other point, is where in the world do you stick your flares and spare handheld vhf where they are easily accessable should a flip situation occur??

The only way I can see is to have a waterproof container attached to the A-frame by a length of rope but loose so that if the worst did happen and you flipped it wouldn't take a great deal to bob under and pull it out past the tubes or it may get thrown clear and be on the outside of the tubes anyway!?!? I'm stumped.....any bright ideas for this sort of situation welcomed.

Just on a pondering note: If my radio is supposed to work at under 1m of water for 3 hrs or whatever it is, then what's the chance if you can't right the boat of being able to send a DSC alert?! Or should I install and aerial on the bottom of my boat too!?!?

It's all scary stuff and you'd hope that this never happens to anyone, but my eyes have been open to how often this does happen. I always thought it was relatively unusual for a rib to flip.......but obviously not. Sod has a very twisted sense of law!!!

P.S. All the boats that have been flipped and mentioned on here am I right in thinking they are all sub 5m? If so then how much does size play a part? Is there a size big enough that this won't happen and the rib will possibly just get swamped instead of flipped?