how to 'Test' drying out

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icarusbop

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Hello:

I have a Beneteau Evasion, and live in a tidal area.
The other day a yacht from the club got stuck on a notorious sandbank and dried out, this apparently happens quite frequently around here...
When the tide came back in she floated fine and came back into harbour.
This made me think:

Beside the obvious: Is there any way I could find out if my lady will re-float OK, if the same ever happens to me?
If I go with the obvious - I understand I watch the water as it goes out and see if it comes over the top and into the boat (theory being the reverse happens when the tide comes in).
If the outgoing water does not get into the boat, the incoming should be fine, this is dandy.
But if the water DOES get into your boat when the tide is on it's way out, you have a few hours to think of a fix before it comes back in... what do you do now?
Dig a hole under the keel?
 
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I can't think why on earth you would want to do that. unless its a bilge keeler.

A few thoughts if you are worried about grounding and drying out.
If you are coming and going in known shallows or sand banks time your arrival for a rising tide and approach slowly. hope fully you will be able to back off. If you touch and stick try heeling boat to reduce draft, Be wary about hoisting a sail to heel it may just drive you further up.
If you are unable to get off
Check the depth around your boat and if possible the type of bottom.
A line with a weight will do the trick.
Make note of your position and tell CG. They might ask for a reduced wake in your vicinity.
If you can get your anchor out into deeper water. take it out with dingy. Tention with winch it may help you being pushed higher.
If you can heel the boat towards the shallower water it is less likely to be a problem,
If you can get a cusion under the boat before the hull touches it may save on repair bill.
If you can plug or seal any openings on low side may help when water rises. batten down all ports and hatches,
Close seacocks on any low side drains, heads, sinks, even above waterline vents should be plugged.
Duct tape over cockpit lockers to seal, put hatch boards in and duct tape round.
Check for damage, leaks
Any weight you can get rid of pump out fresh water tank take stuff ashore may help.
I'm sure there are few other tips I have not thought off.
Digging a hole for keel may help. even better a trench to deeper water
 
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perhaps some thought might be given to making temporary legs with a spinnaker pole and some floor boards, so that the boat does not lean too much.

I have also seen a liferaft used to provide extra bouyancy under the hull and give 'lift' to the rising waters. Perhaps fenders can be similarly deployed.

If the boat is really tilted over, will the batteries drain the contents into the bilge, and also become useless for pumping/starting ?
 
Grounding and drying out in most boat is just an inconvenience in good weather. In rough conditions it's best avoided as there is great potential for damage ocurring as she shifts in the surf. Unless you want to put it to the test, the best way to set your mind at rest is to get a section of the widest point of the boat and simply draw a line from the tip of the keel tangential to the topsides, representing the waterline as she starts to refloat. In most cases, the line is unlikely to even reach the gunwhales and your decks, coamings, etc. will keep any water out. Modern boats with high freeboard are even less vulnerable although some open boats may be at risk. In my case, I found out the hard (and very public) way that Mojo settles at about 40 degrees with near enough the same freeboard as when upright - on the beach at the entrance to the Hamble!

Rob.
 
I had a a Mashford 4 tonner that drew 4 foot and had 7.5 beam so it layover at quite an angle.Even so as the tide came in the boat began to lift as the water reached the rail.There could be a danger from waves breaking over the boat before it floats but thats err extreme.If you have a deep draught but wide beam it should be ok.Making tea whilst whiling away the hours till the tide returns is worthy of cosideration.
 
Normally the best way to achieve satisfaction is to 1. ensure batteries and other potential disaster "spills" are taken care of and then get over the side and start scrubbing the exposed bottom, as if it was planned. Few yachts will be swamped unless it is rough.
 
Thanks to all for the messages:

Around here we are surrounded by sand when the tides go out, so nothing more than a scrapes should happen to the hull - as long as she re-floats OK.
I'm not planning on drying out on purpose, just wondered if there is any way to calulate what would happen.
Some yacht of other gets stuck on the sandbar approx once every six weeks apparently, either I am surrounded by rubbish sailors or something else is afoot with the shifting sandbar and marker buoy (which is sometimes out of place)
 
My old folkboat got stuck up the bank in Butley Creek during a thunderstorm, with the mast pointing down hill. The other boats opened a book on what would happen as the tide came back in. Despite my panic she just bobbed up.
 
One thing to check is the heights of the next couple of tides.
If the tides are 'taking off' ie the height of the next HW is less than todays watch you don't get 'neaped by the tide and are unable to get off.
Only happens of course if you dry out right at the top of the tide.
If you are really unlucky it will be about 2 weeks till the tides make back up and float you off
 
If you have any drawing of your yacht available you could draw a line from the base of your keel to the outer of the hull at its broadest point,this should give you the maximum angle you would heel, the beamier the hull and shallower the keel the higher she should be out of the water; however if on a shelving beach or bank the stern may be lower for a time and subject to incoming waves before flotation takes place.

ianat182
 
If you want to 'test' drying out, would it be possible to do it in a drying harbour? Attach some lines to the harbour wall winch the boat up if all starts to go wrong.
 
Here's one I prepared earlier :)

DriedOut_zpse900529a.jpg
 
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