taking in bilge water

[loribear]

hi all ive noticed that alot of boats can't get under certain bridges because of the height of the river, when we used to travel on the trent when i was a youngster you used to see barges taking in water to weigh the boats down,i'm suprised that nobody's ever thought of a way to do it with hire craft, or would it be too dangerous for fibreglass boats to do that, they could take in water before they go under the bridge then bilge out once they'd got through. lori

[Antares_9]

Have you considered the tonnage of water that the average 40' hireboat would need to take on to lower the freeboard by say a paltry 6"", and more importantly have you thought about the crap that would be mixed with it when it was pumped out? The time it would take to take on and discharge the water?

A commercial barge with possibly three phase pumps is one thing a hireboat with 12v pumps suited t clearing a bit of shaft seal seepage is another entirely, in an emergency with portable 2" or greater petrol / diesel powered pumps perhaps, but not otherwise I fancy.

[Hockham Admiral]

Back in '81 we had a Colvic 30 and were stuck in Lincoln wanting to go under the Glory Hole..............

As it's non-tidal (locks both ways) we did indeed flood the bilges to about half way up the engine........

However it was a brand new boat and the bilges were squeaky clean! I certainly wouldn't do it with this Friday Girl!

[BuffaloBill]

Not forgetting that if you have a bowthruster, YOU DON'T WANT WATER IN THERE!

A friend of ours had problems with their bilge pump and the bowthruster got drowned

in water and needed a new one as too much damage was done to repair it.

[loribear]

Back in '81 we had a Colvic 30 and were stuck in Lincoln wanting to go under the Glory Hole..............

As it's non-tidal (locks both ways) we did indeed flood the bilges to about half way up the engine........

lincs 001.JPG[/attachment][attachment=1]lincs 002.JPG[/attachment] but even though it was'nt tidal when the river rises the currant could be quite strong,[attachment=0]lincs 003.JPG[/attachment

] which could whip you through quite quickly. lori

[Guest]

We normally achieve the same effect when victualling the boat and taking on the wine rations- only one problem - as we approach the end of the week we get under fewer and fewer bridges. !

James

[Guest]

I read somewhere that one tonne of ballast will lower a vessel by 1" ?

Or you could try this formula which I pinched from another forum:

Tonnes per centimetre (TPC): This is the mass required to increase or decrease a ship's mean draft by 1 cm. This value varies only according to the waterplane area (Aw), and the waterplane area can vary according to the ship's draft. Therefore, the TPC can vary according to the ship's draft.

TPC = Tonnes per centimetre immersion

TPI = Tonnes per inch immersion

3.2.4.a.(i) Example 1

A rectangular barge having a length of 20 m and breadth of 12 m is floating in salt water (Ï = 1,025 kg/m3).

What is its waterplane area?

What is its TPC?

Find the waterplane area:

Aw = (length × breadth) at the waterline = 20 m × 12 m = 240 m2

Find the TPC:

TPC = (Aw×Ï) ÷ 100 = (240m2 × 1.025) ÷ 100 = 2.46 tonnes

This means that loading 2.46 tonnes on the ship will increase the draft by 1 cm. You can also say that unloading 2.46 tonnes from the ship will decrease the draft by 1 cm.

So generally you're gonna need an awful lot of water on board to make any significant change to the boat's draft.

[pks1702]

I have an aversion to water in my bilges

[andyg]

well their you go i learn something new everyday on this forum, lori iv walked up them stairs on to the high st many times, i love walking along the river through the town. the outlaws live just up the road near raf scampton. never knew it was called the glory hole.

[loribear]

well their you go i learn something new everyday on this forum, lori iv walked up them stairs on to the high st many times, i love walking along the river through the town. the outlaws live just up the road near raf scampton. never knew it was called the glory hole.

hi andyg i can't believe how much it's changed, with all them student accomodation flats, & i really miss that lovely little club house pub, where they've built that big pub called the shed, why could'nt they have called it the brayford instead, & i used to like seeing that barge at the other side of the glory hole, that used to sell fish, & i still love to visit lincoln now & again, somewhere in braydon pool is my mums wedding ring, from when dad went & dropped it, plonker. lori

[Antares_9]

used to like seeing that barge at the other side of the glory hole,

I prefer something else the other side of a glory hole.