Measuring the draught

[magnetman]

Or even 'accidently' leave your key in the handcuff. Then just wait topside, somewhere safe along the canal. Yobs will find the key, and drain the pound.

 

Trust me, this works. On our Foxton trip http://www.angelfire.com/rnb/malcsworld/boat/Foxtontrip.html

 

we accidently found this out.

 

Magnetman - have you found the windlass yet (as I asked in a previous post)

 

My boat is one of those weird ones which actually does have a lowered skeg to get a big prop in which tends to make the back of the boat heave up when passing over motorbikes and the odd trolley and also makes 'relevant draught' a bit of a point. I'll get round to the windlass when I'm next there, Kilby Bridge area wasn't it?

As for accidentally draining pounds and locks, I think this is very irresponsible and should not be encouraged.

 

it!

[Liam]

You could also catch all the big fish that are flapping around in the pound, like foreigners are doing to some of our waterways.

 

No, don't. I am joking.

[Theo]

I'll do that. We thought about 30 inches. The skeg is a protrusion of the base plate not a welded on after thingmajiggy.

Guffaw

It's amazing how much lower she sit's in the water, when all the tanks are full.

 

I was atsounded, yes atsounded, to note that, when pumping out the water tank which had just been disinfected with a couple of bottles of cheap imitation Milton, to note that wne the water tank finally pumped dry the anodes were clear of the water by about 2". Normally they are submerged by at least that so with a width of about 4" for the anode that looks like an 8" draught change forward, just for the weight of water in the tank.

 

Nick

[allybsc]

If you have a flight of locks close by "accidently" drain the pound, and do it that way

 

 

Yeahhhhhhh, cracked it Liam...our pound is 17 miles long...guffaw

[magnetman]

I was atsounded, yes atsounded, to note that, when pumping out the water tank which had just been disinfected with a couple of bottles of cheap imitation Milton, to note that wne the water tank finally pumped dry the anodes were clear of the water by about 2". Normally they are submerged by at least that so with a width of about 4" for the anode that looks like an 8" draught change forward, just for the weight of water in the tank.

 

Nick

 

Don't know the length but if it was 55ft that'd be about 1o tons per foot immersion I think, which would make 8 inches (in the centre) look like 7.5 ton which means it must be 3.5 tonnes of water as it is at one end of the boat. that is a seriously big tank.

[GRPCruiserman]

Don't know the length but if it was 55ft that'd be about 1o tons per foot immersion I think, which would make 8 inches (in the centre) look like 7.5 ton which means it must be 3.5 tonnes of water as it is at one end of the boat. that is a seriously big tank.

 

There aew some Narrowboaters who, when traveling The Ribble Link which includes two strong tidal rivers, the Ribble and Douglas, with their water tank at least half empty (or should that be at most half full !!), to raise the bows over the waves.

 

All the cruisers I've had have had the water tank in the middle of the boat, which does not then affect the trim of the boat for river work when filling.

 

If I was having a Narrow Boat built, I would design it like an elongated Dawncraft, giving the best and most practical layout with the maximum storage. I've yet to find a narrow boater who has enough storage space. We had many empty lockers in the Dawncraft there were that many. I would certainly position the water and fuel tanks in the middle of the boat, not at the ends like most narrow boats.

[Supermalc]

I'll get round to the windlass when I'm next there, Kilby Bridge area wasn't it?

 

Cheers Just a few locks downstream. It fell in inbetween the boat and the towpath, on the right hand side.

 

Just for the hell of it, I've been tempted to return and try to find it. Leave my car at Kilby Bridge and walk back.

 

Strange I suppose, but I value stuff I find, and restore/clean up etc. far more than if I buy it new.

[magnetman]

Cheers Just a few locks downstream. It fell in inbetween the boat and the towpath, on the right hand side.

 

Just for the hell of it, I've been tempted to return and try to find it. Leave my car at Kilby Bridge and walk back.

 

Strange I suppose, but I value stuff I find, and restore/clean up etc. far more than if I buy it new.

[Theo]

Don't know the length but if it was 55ft that'd be about 1o tons per foot immersion I think, which would make 8 inches (in the centre) look like 7.5 ton which means it must be 3.5 tonnes of water as it is at one end of the boat. that is a seriously big tank.

 

60' Boat. Next time I fill up I will do some timings and get a rough measure of the volume.

[Theo]

60' Boat. Next time I fill up I will do some timings and get a rough measure of the volume.

 

I think that there might be a miscalculation. 8" fwd, as long as there were no draught change aft would mean a mean draught change of 4". In fact I would suspect that there would be a slight increase in the after draught. If this is the case then the mean change of draught would be rather less than 4", say 3" which is 0.25 ft. At 10t/foot that would give 2.5t. Does that sound more reasonable?

 

Nick

[GRPCruiserman]

If a narrow boat tank holds on average 70 gallons, or 70 x 1.25lbs x 8 pints, that's about one third of a ton.

 

If the water tank was in the middle, and the boat weight was about 15 tons, that should only take it down about half an inch.

Edited December 23, 2006 by GRPCruiserman

[GRPCruiserman]

I think that there might be a miscalculation. 8" fwd, as long as there were no draught change aft would mean a mean draught change of 4". In fact I would suspect that there would be a slight increase in the after draught. If this is the case then the mean change of draught would be rather less than 4", say 3" which is 0.25 ft. At 10t/foot that would give 2.5t. Does that sound more reasonable?

 

Nick

 

That's still about 500 gallons !!

Edited December 23, 2006 by GRPCruiserman

[ChrisPy]

My boat is one of those weird ones which actually does have a lowered skeg to get a big prop in which tends to make the back of the boat heave up when passing over motorbikes and the odd trolley and also makes 'relevant draught' a bit of a point.

that's the narrowboat version of an icebreaker - someone has to keep the navigation open

[DHutch]

My boat is one of those weird ones which actually does have a lowered skeg to get a big prop in which tends to make the back of the boat heave up when passing over motorbikes and the odd trolley and also makes 'relevant draught' a bit of a point. I'll get round to the windlass when I'm next there.

Yeah, i saw somone fabricating one of those last year. (cant remember where, banbury way possably?)

- It looked most unlikly, this fairly slender looking peice of steel work sticking 8inches down from the baseplate protecting a very vunerable looking propeller and rudder!

 

 

Daniel

[GRPCruiserman]

Yeah, i saw somone fabricating one of those last year. (cant remember where, banbury way possably?)

- It looked most unlikly, this fairly slender looking peice of steel work sticking 8inches down from the baseplate protecting a very vunerable looking propeller and rudder!

Daniel

 

This kind of design would reduce the amount of water pulled from the side of the canal, and therefore the amount of wake created.

[allybsc]

Well... I tried the tape measure but the water pushed away from the side of the boat, I tried the pole but I couldn't feel any sort of lip or ridge on the base plate and it was peeing down and windy so I didn't take off the weedhatch, so the mystery continues, I may have to wait untill the next docking to do it properly.

[John Orentas]

Well... I tried the tape measure but the water pushed away from the side of the boat, I tried the pole but I couldn't feel any sort of lip or ridge on the base plate and it was peeing down and windy so I didn't take off the weedhatch, so the mystery continues, I may have to wait untill the next docking to do it properly.

 

 

 

Don't bother going down the weed-hatch, if the bottom-plate does not protrude, knock a nail in a piece of wood and use that as a gauge, do it at about mid-ships and that will give you the 'average' draught. Forget about the skeg being below the bottom the majority of boats are like that it won't interfere with mooring as it will always be at least 3.5ft from the bank and when underway it will simply plough it's way through the silt on the canal bed, you won't even be aware of it.

[magnetman]

Don't bother going down the weed-hatch, if the bottom-plate does not protrude, knock a nail in a piece of wood and use that as a gauge, do it at about mid-ships and that will give you the 'average' draught. Forget about the skeg being below the bottom the majority of boats are like that it won't interfere with mooring as it will always be at least 3.5ft from the bank and when underway it will simply plough it's way through the silt on the canal bed, you won't even be aware of it.

could use a boathook to hook under the baseplate and measure the draught that way, if its painted just put a marker pen or yr finger on it. works for me and its a nice way to check moorings in advance for depth too, and you can hook out the odd coalbag as well.

[allybsc]

could use a boathook to hook under the baseplate and measure the draught that way, if its painted just put a marker pen or yr finger on it. works for me and its a nice way to check moorings in advance for depth too, and you can hook out the odd coalbag as well.

I'll give both a go next weekend, I'll try it in daylight this time