Dipping under a bridge

thejonesey

thejonesey

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Okay, so my boat airheight is 3.76m and Cookham lock cut bridge is 3.81. I know that there are loads of variables but a number of people have suggested that I nose up to the bridge and then floor the throttles. Has anyone used this method and if so, how much does the boat actually dip? I am not sure I have the bottle but....
 
0.05 metre is about 2" according to mr rudimentary estimation.
Headwater level could be anywhere between -3" and +6" a likely to be a bit more rather than less. Heading upstream you can ask lockie (if on duty) but more difficult heading down.
is your airdraft with full tanks? How many heavyweight friends can you embark ?
 
I have heard of this being done at Windsor Bridge in a Broom 35 Sedan , the name of it was 'Purbeck Illusion' and they were members of PHYC when my parents had a boat there.

The skipper approached it in reverse slowly , then gave it full throttle reverse which dug the stern in nicely and got it under.

You'd have to have much bigger balls to do it by slamming the throttles forward. Reverse is a much safer bet.

Remember too that bridge heights are measured from HW , and typically the locks run above headwater , up to 8 inches at some.
 
boatone said:
0.05 metre is about 2" according to mr rudimentary estimation.
Headwater level could be anywhere between -3" and +6" a likely to be a bit more rather than less. Heading upstream you can ask lockie (if on duty) but more difficult heading down.
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I have lockies number so can call ahead to check headwater height. He has also offered to drop the height of the river briefly by doing something too!
boatone said:
is your airdraft with full ? How many heavyweight friends can you embark ?
Click to expand...
tanks full as is beer fridge....Any volunteers?

Back to the question? Anyone brave enough to try this?
 
Open the seacocks fill to just below cabin floor , go through bridge then switch bilge pumps on and bob is your father/mothers brother !

edit if your bilges are clear should be clean aswell after !
 
thejonesey said:
Okay, so my boat airheight is 3.76m and Cookham lock cut bridge is 3.81. I know that there are loads of variables but a number of people have suggested that I nose up to the bridge and then floor the throttles. Has anyone used this method and if so, how much does the boat actually dip? I am not sure I have the bottle but....
Click to expand...

There's "Seaduction", another F43, moored at Hambleden lock upriver of Cookham. I know he goes down past Cookham so it must be possible :confused:.
 
I was tought to approach at say 6 knots abd as the bow got to the bridge take the power right off so the bow dropped and then open her right up so that the stern squats, this was on the Norfolk Broads by the Pilot at Potter Higham. It worked every time, try a bridge not so low first witha sacrificial beer can to gain confidence.
 
Perry said:
I was tought to approach at say 6 knots abd as the bow got to the bridge take the power right off so the bow dropped and then open her right up so that the stern squats, this was on the Norfolk Broads by the Pilot at Potter Higham. It worked every time, try a bridge not so low first witha sacrificial beer can to gain confidence.
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Exactly how we sometimes get Ex Libris through shallow water if we know about it. Plus stick everybody forward. Apart from the helm. We learnt that last bit....
 
Takes a bit of courage to do all of this. A lock cut is perhaps the best spot to try it given no stream but I would still want people up top that I trusted.
 
I have known boat owners that have tried the foolhardy approach of opening up the throttle to attempt going through a bridge and have met with disaster. Ask yourself these questions, Is my insurance going to cover me if I get it wrong? Could I afford the repair bill if I try it and get it wrong and I'm not covered by my insurance? What would happen if I caused a large push of water and made it through but the surge caused damage to another vessel? Would I have to pay for the damage? Would I be able to afford it? Would my insurance cover me? Would I be prosecuted by the EA? Could I lose my Thames licence?
In my opinion it's much wiser to ask the Cookham Lock keeper to help, it is possible for him to open the lock sluices just as you are about to go through and that will drop the level by a few inches to help. Alternatively you can formaly request that the Head Water be reduced to allow passage, the lock keeper could then arrange a suitable drop in level to the standard head water level to achieve the published height of the bridge to then allow passage through.
 
A.Cost of repair £2-3K.Your boat will be a legend on the river, the interweb and in the council accounts(Bridge dept.)
People will lower their voices and smile when you walk into the marina bar for years to come.

or

B.Hinge arch £1200 quid and sleep at night. ?
 
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Our previous boat was very marginal at Cookham lock cut bridge. Had to remove the flybridge screens, approach the bridge very slowly and stop a couple of inches short. Check the wheel would just get under, lie across the helm seats and reach up to ease the throttles into forward. Only got stuck once on the wrong side of the bridge and the lock keeper kindly dropped the water level a few inches for us.

In 2010 we had cleared the bridge heading downstream and were waiting outside the lock. A flybridge cruiser followed us down but he was on the lower helm position (you can guess what's coming). He had slowed right down seeing we were moored up for the lock and was probably only doing a knot or two but hit the bridge. The noise of strained, cracking fibreglass was awful. And very loud. He slammed it into reverse, backed off, pulled over and was inspecting the damage as we then went into the lock.
 
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