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Old 08 November 2009, 15:48   #21
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I'm surprised that people think this is scandalous neglect, and a "people shouldn't be allowed to have boats and not look after them attitude". I think its quite possible for this to happen in just a few days - especially if the transom is low/cut down.

Many people will leave there boats afloat and not be able to visit them for a couple of weeks, if a battery dies or a pump/float switch fails then problems quickly escalate. If circumstances conspire against you and it turns out you don't get down to your boat for a month - then shit happens - and your glad you bought a RIB so its still afloat, and hopefully glad the boat was well rigged with electrics and fuel breather etc. out of the water.

I know of one sailing club where the boats are normally used twice a week and its still not uncommon for their rib to be very full of water in bad weather.
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Old 08 November 2009, 17:08   #22
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I'll wake up to find myself gaffa taped to a console with 3 feet of Homebase drain pipe up my arse.

Takes me back to school days hey gotchiguy?
I knew they were a bit odd near Stroud...
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Old 09 November 2009, 07:46   #23
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I'll second the "doesn't take long" thing. Once worked at a place with a fleet of moored wayfarers. One night of heavy rain & most wre up to the top of the bouyancy tanks. On the plus side to this, it shows you how reliable a swamped rib is at staying afloat!


As for the mooring thing, Pol is spot on with the damped load, however you also have to remember that the swamped boat is still only displacing the amount of water the hull / toobs can displace. the water inside is part of the medium it's floating in (as I assume there is a free flow iof water over the transom by this point).

Yes, if you tried to tow it, you'd feel the full effect of the ton or so of water, as you are trying to shift the whole lot. But when moored, I'm with Polwart on the windage theory.
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Old 09 November 2009, 08:01   #24
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Quote:
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I'm surprised that people think this is scandalous neglect, and a "people shouldn't be allowed to have boats and not look after them attitude". I think its quite possible for this to happen in just a few days - especially if the transom is low/cut down.
Surely if you know your boat has a low transom etc you would take more care / check more often , or pay someone to if you knew bad weather was on the way?

Just seems a huge shame.

As an aside I'd go with the view of the mooring being under alot more stress. Windage is bugger all either way as its a swinging mooring by the look of it - but it will have a few tons of water to restrain. Yes it will move less , but looking at the momentum you have to restrain in the extra mass. I dont think you can consider it as a free moving mass of water inside the boat . If that was the case the flooding hull on Seariders wouldn't work !
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Old 09 November 2009, 08:24   #25
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But that's WHY they work - boat sits low in the water with less windage & more momentum, so moves a lot less.

Accelerate hard & the laws of physics say that the water wants to stay put and becasue it's not entirely restrained (the big hole) kinetics forces it out the back.


Could the ratings on a mooring be the breaking strain of the chain?
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Old 09 November 2009, 10:30   #26
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But that's WHY they work - boat sits low in the water with less windage & more momentum, so moves a lot less.

Accelerate hard & the laws of physics say that the water wants to stay put and becasue it's not entirely restrained (the big hole) kinetics forces it out the back.
If you are right then it is possible to accelerate gently in a Searider and keep all the water in the hull.

Surely it is good old gravity that drains the hull? As the boat rises, nose first, from the water.
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Old 09 November 2009, 10:36   #27
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Could the ratings on a mooring be the breaking strain of the chain?
Mooring chain is normally sized to last a couple of years and still be strong enough to be able to lift the sinker. The boat bobbing around on the top is usually the least of its problems.
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Old 09 November 2009, 11:01   #28
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Surely if you know your boat has a low transom etc you would take more care / check more often , or pay someone to if you knew bad weather was on the way?

Just seems a huge shame.
Maybe, but maybe the owner knows that his electrics are all OK, and his fuel tank is either not on board or well above the flooded waterline - in which case apart from having to bail like mad he's not really any worse off is he? and probably less likely to get nicked too!
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Old 09 November 2009, 11:34   #29
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The passing of an average Spring/Summer depression in these parts (3/4 days-ish) would often fill Moon Raker to transom level, with no chance of me being able to row out to her because of the wind. She could be sitting there full of water for a week. She was much more stable in the wind and waves. She wasn't being neglected though - I can see her from most of the windows in my house. Two reasons made me fit another pump with a float switch.

First, I got fed up of getting aboard into a swimming pool. Second, when laid up last year, I opened up the drain hole from the hull to find water inside. I reckon this was getting in via the console and seat holding down bolts. A foot or so of water head may have forced water past any sealant. It's probably adequate for a wet deck and the odd slosh of water.

I shall check on the next fine day.
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Old 09 November 2009, 11:58   #30
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If you are right then it is possible to accelerate gently in a Searider and keep all the water in the hull.
Well, I don't know about you, but I certainly have never managed to empty a searider at tickover....... Remember at sub planing speeds, the water pressure at the exit hole will be more than enough to counteract the momentum.

Problem is you need to get on the plane, and to do that you have to force some of your ballast out the back against the water pressure. Granted if you got 60 on the back of your SR4 this discussion is slightly irrelevant, as it will plane regardless, but for a laugh try it on one with the minimum rated HP on the back!

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Surely it is good old gravity that drains the hull? As the boat rises, nose first, from the water.
Aye, and once the nose is in the air the stern is forced down, so the back pressure on the exit hole is higher...... Once you're PROPERLY on the plane gravity is in full effect, but you need to get up there first - I assume you've not seen / experienced the "permanent nose in the air" trick at mid throttle or with a smaller engine?
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