Raw water cooing and the risk of sinking

[Theo]

It has just occurred to me to worry about the fact that there is a flexible hose from the mud box to the water pump. The opening to this hose is from a point in the mud box below the waterline. If the hose were to be damaged I cannot see any reason why the boat would not sink. I would think it sensible to fit a stop cock to this and as a matter of course shut the cock whenever the engine is not running.

 

Or am I being unnecessarily pessimistic/fussy?

 

Nick

Edited January 28, 2007 by Theo

[fuzzyduck]

Nope, makes perfect sense to me, as a matter of course all below the waterline skin fittings should have stopcocks, for the very reason you identified. In addition their operation should be checked regularly.

Edited January 28, 2007 by fuzzyduck

[Theo]

Nope, makes perfect sense to me, as a matter of course all below the waterline skin fittings should have stopcocks, for the very reason you identified. In addition their operation should be checked regularly.

 

One inconvenience is that I will have to lift one of the engine compartment boards every time I operate it. I am wondering if I can organise some sort of remote operation for it. Something in the nature of wires and pulleys. I wonder if a couple of bicycle brake cables would to the trick.

 

Nick

[blackrose]

One inconvenience is that I will have to lift one of the engine compartment boards every time I operate it. I am wondering if I can organise some sort of remote operation for it. Something in the nature of wires and pulleys. I wonder if a couple of bicycle brake cables would to the trick.

 

Nick

 

Some sort of reminder to open it by the ignition switch would probably be a good idea too. The only problem with operating it remotely is that you've got to make sure it can't be closed accidentally. Another issue is that the stopcock does nothing if the hose is damaged or comes adrift while you're moving. I suppose the first you'd know would be an overheating engine. How about a washing up bowl under the pipe with a water level alarm (£5 from Maplins). The sensor could go in the bowl and the alarm stays somewhere dry on deck. Then at least you have an early warning.

[magnetman]

Water alarm is a good idea I reckon, or a float switch wired to a motorised stop cock perhaps.

[Theo]

Some sort of reminder to open it by the ignition switch would probably be a good idea too. The only problem with operating it remotely is that you've got to make sure it can't be closed accidentally. Another issue is that the stopcock does nothing if the hose is damaged or comes adrift while you're moving. I suppose the first you'd know would be an overheating engine. How about a washing up bowl under the pipe with a water level alarm (£5 from Maplins). The sensor could go in the bowl and the alarm stays somewhere dry on deck. Then at least you have an early warning.

 

 

That sounds a brilliant idea if I can make some assumptions about where the hose might start leaking. It snakes its way under the engine from the port side to the starboard before rsing agin to its coupling on the vee belt driven water pump

 

I suppose that there is a warning that something is going wrong if the steerer notices that the water is no longer being squirted out of the exhaust.

 

Nick

[Guest]

Definitley fit a stop cock. Our old raw water cooled boat had one. Like you say it is a pain lifting the engine boards, and i often intended making an extension with a socket set long reach adaptor aand nuckle joints and bringing it through a stuffing gland on the floor of the boat. Never did get round to it.........

 

That sounds a brilliant idea if I can make some assumptions about where the hose might start leaking. It snakes its way under the engine from the port side to the starboard before rsing agin to its coupling on the vee belt driven water pump

 

I suppose that there is a warning that something is going wrong if the steerer notices that the water is no longer being squirted out of the exhaust.

 

Nick

If it is the type that mixes the cooling water with the exhaust, then an exhaust temperature alarm is the best way. I think I remember Supermalc has done this on his raw water cooled Yanmar?

[Supermalc]

If it is the type that mixes the cooling water with the exhaust, then an exhaust temperature alarm is the best way. I think I remember Supermalc has done this on his raw water cooled Yanmar?

 

Yes, very simply. Just bought a small thermometer with a probe on a wire, that I taped onto the top of the elbow.

 

 

http://www.thermometersdirect.co.uk/

 

You can see the tape on top of the raw water elbow.

 

 

And if you look carefully you should just see the thermometer on the right hand side of the steering wheel. It's got the added advantage of not only telling you the wheelhouse temperature, but also the temperature of the engine.....handy when frosty.

 

 

 

It's inbetween the radio handset, and the switchpanel.

[DHutch]

Our condensor is raw water cooled, so we have a very simualar setup for that.

- And for the reason you suggest, we do have a large stopcock on the exit of the mud box, which we turn on/off every day.

- For use its not a big job at all, its only one of about eight valves we have to operate to get going, and gets done with two others when we oil the engine. And ofcause its all in the engineroom and (relativly) easyish to get at.

 

In your shoes, i would proberbly fit a 1/4 turn ballvalve as the valve in question, with an extented arm purtruding the sterndeck.

- Or possably and extended arm that had a socket/fitting just below the deck, with a key on your engine keys to operate it each time.

 

You would have to remember. But if you just made it part of the routine, and stuck to it, you could. Thats how we do it.

 

 

Daniel

[Semitrad]

Could some sort of physical interlock be used? for example a metal box to keep the engine start key in that can only be accessed by turning the stopcock to the on position - or is this too complex?

[magnetman]

Could some sort of physical interlock be used? for example a metal box to keep the engine start key in that can only be accessed by turning the stopcock to the on position - or is this too complex?

 

Certainly a small reed switch or similar could be wired to the stop cock and through a relay it could interrupt flow of electricity to the starter solenoid until the stop cock was opened. This looks like a workable system to me, specially if the stop cock was of the sort which has a lever handle rather than a circular one - easy to fit a magnet and reed switch or even a small click switch to that.

 

A similar system is available for the PRM160 gearbox to make starting in gear impossible by switching the starter solenoid wire (I believe) off when in forward or reverse.

[Theo]

Certainly a small reed switch or similar could be wired to the stop cock and through a relay it could interrupt flow of electricity to the starter solenoid until the stop cock was opened. This looks like a workable system to me, specially if the stop cock was of the sort which has a lever handle rather than a circular one - easy to fit a magnet and reed switch or even a small click switch to that.

 

A similar system is available for the PRM160 gearbox to make starting in gear impossible by switching the starter solenoid wire (I believe) off when in forward or reverse.

 

 

The reed switch idea appeals. I had already decided on the ball valve arrangement. The reed switch interlock may have to wait, either until I have less pressing things to do or until forgetting to turn it on brings it to the top of the list! I imagine that a stainless ball valve will do the job nicely. Is there any way around drydocking to do the job? Possibly using a lock cill to lift the stern a tad?

 

Thanks all

 

Nick

[magnetman]

The reed switch idea appeals. I had already decided on the ball valve arrangement. The reed switch interlock may have to wait, either until I have less pressing things to do or until forgetting to turn it on brings it to the top of the list! I imagine that a stainless ball valve will do the job nicely. Is there any way around drydocking to do the job? Possibly using a lock cill to lift the stern a tad?

 

Thanks all

 

Nick

I wouldn't fancy the cill idea much, too easy to have a nightmare there, the boat comes down on the skeg and rolls over sideways and can bugger up the rudder.

If the baseplate needs to be clear then I'd think craning might be the thing cos it's got to come out 18" to 2ft which is too much really for a block and tackle on a bridge. Are you talking about water coming in or replacing the whole fitting, if its just the water coming in I'd say a rubber plug would stop it pretty quickly.

[Supermalc]

Is there any way around drydocking to do the job? Possibly using a lock cill to lift the stern a tad?

 

DON'T even think of going there. I got into the mother of all rows by putting a strap across and dropping the lock a foot, to lift the back of my little boat to only look at the prop.

 

Purely my own fault, and all documented elsewhere.

 

Can't it be fitted with the boat in the water? I changed my propshaft without taking mine out.

[alan_fincher]

I agree with what others have said....

 

Trying to dry dock one end of a boat on a lock cill has been done by people in emergencies, but even if it goes well, I shudder to think of the stresses and strains it puts on the boat. (Supporting at an extremity is nothing like putting straps somewhere near the middle and lifting.

 

I do know however that where people have access to a STAIRCASE lock, they have sometimes been used unofficially for this purpose. (I've seen stories of Union Canal Carriers boats being "docked"in the upper chamber of the Bascote Staircase, to alklow emergency work on stern gear).

 

But for the cost of an hour or two in a dry dock, it ain't worth it. (And clearly BW or your insurance company would frown heavily on anything like this!).

 

 

I know little about mud boxes, but wonder if they work so that you can take a top off them, which is still above waterline, and then reach down in them to clean them out ?

 

If so, can you not bung up the hole from the mudbox, to the outlet pipe, with something from inside the mudbox, which will then allow you to make any necessary changes to the "plumbing" on the outside of it, (.... to add a gate valve, or whatever ?).

 

But if my mental picture of how I think they work is a load of cobblers, simply ignore this as a rather useless suggestion

[Jon]

Moving to Boat Building & Maintenance

 

Jon

[Hairy-Neil]

Farm irrigation and slurry pumps I've worked on often have a device that kills the engine when the water supply stops. They also have a link to the oil pressure switch and water temperature sensors so the engine dies if either of those is lost too. To start the engine, obviously an override button must be fitted, held in manualy till the engine fires up. Once all the fluids are up to pressure etc. the override button can be released and the "fail safe" takes charge. (Many's the time I've come across an engine with the override button wedged in, taped up with gaffer tape or otherwise bypassed by ..... ) The name Murphy rings a bell as the co. that supplies these devices. They are useful on a farm as the machinery is often left to its own devices for hours or even days on end. However,........

 

... there are times on a boat when you could be put in a life threatening situation if the engine died because it was slightly overheating so these devices are not ideal for marine use. Warning lights or buzzers are a much better bet.

 

........... (And clearly BW or your insurance company would frown heavily on anything like this!):

 

The BW lengthsman at Hanwell flight on the GU once drained down one of the short pounds, then willingly donning chest waders, set to cutting the car tyre fron Nuneaton's blades.....whilst a queue formed and a crowd gathered to watch....

 

Is there any way around drydocking to do the job? Possibly using a lock cill to lift the stern a tad?

 

How big/what form is the inlet?

 

A plastic shopping bag laid over the hole is often sufficient to stop 99% of the flow. I've seen canal societies dam a whole canal off with a sheet of polythene and a scaffolding skeleton.....

Edited January 29, 2007 by Hairy-Neil

[DHutch]

Yeah, the micro/reed switch sounds like a workable plan if you wanted.

 

As for fitting it.

- DO NOT try and lift the stern on the skeg. It will almost certainly bend under the wieght of the boat, not at all good, espically if your under it at the time!

 

It is possbable to use a beam accross a lock and heavy loadstraps to lift boats (this is what BW do when people sink boats in locks), and its also possable to sit a boat on the bottom in a staircase lock, or even a short pound.

- What you do is upto you, but i would certainly say its frowned apon.

 

Also worth beairng in mind that without the water holding them, banks can occational fall into the canal, which would be very embaressing for you! - And simaualy, the bottom of the staircase lock or pound may not be flat.

- Although we have accedently sat emilyanne on the bottom of a staircase when a paddle stuck open (it was winded right down, but the actual paddle was still partly stuck open)

 

 

 

You mention it has a mudbox, so i presume its simular to our setup, with a matrix of holes though the hull into the mud boxs (ours is about 12*18inches, with maybe 800*6mm holes.

- However, could still block this with a sheet of plastic helding place my magnets or a freind.

- It wouldnt do a 100% job, but asuming nothing when overly wrong you would be fine.

 

Depends what the set ups like, and what the threads look like.

- But assuming it looks ok, you should be able to unscrew the hose, and replace it with valve (in closed possition ) fairly quickly and smoothly.

- Have some tape/plastic/string/etc to hand incase you need to cover over the pipe if it goes wrong, and have a few buckets, and a decent electric bildge pump to hand. Should be fine...

 

 

 

Daniel

[Theo]

Many thanks for all the good ideas, especially the warnings about propping the stern up on the cill. In view of all this I will not think of it again!

 

I have not yet investigated the end of the steel pipe from the mud box. I don't know if it is threaded or not. The polythene sheeing idea sounds good. Just in case something goes amiss I will borrow a large rubber bung from the lab technicians. I amn not too concerned as the head of water is only an inch or so.

 

Just to answer the query from further up, the mud box has a clamped on cover rather like a smaller version of the weed hatch.

 

As a further modification I am thinking of fitting a tee to this pipe with a funnel arrangement of the end. I will use this to introduce antifreeze into the raw water as necessary. At the moment I have to introduce it throught the mud box and, since the volume of the mud box is quite large I feel that there is considerable waste. With the tee and funnel arrngement I will be able to reduce the use of antifreeze ot abot 1/20 (a wild guess!)

[Theo]

Just had a read of the "Winterising" thread. It occurs to me that I I add the tee as above I will be able to use it to facilitate a drain down. Then I won't need to pollute any more of the cut with bits of antifreeze.

[DHutch]

Just to answer the query from further up, the mud box has a clamped on cover rather like a smaller version of the weed hatch.

Yes, of cause it does! (so does ours)

- Well in that case, take the lid of, reach down, and stick the aformentioned rubber bung in the whole from that side!

 

And as you say, its also quite possable the pipe isnt threaded. The hose my just be pushed on over the steelwork and secured with a jubileeclip.

- In which case you may have to cut a thread some how...

- However the easyest thing might be to get a lenght of pipe with the thread already cut at one end, and weld that into the mudbox, or the exsisting pipe?

 

Whens the boat next do for blacking??

 

 

 

Daniel

[Theo]

Yes, of cause it does! (so does ours)

- Well in that case, take the lid of, reach down, and stick the aformentioned rubber bung in the whole from that side!

Can't do that I fear. A perforated pipe is elbowed down into the mud box. Can't think why. I would have thought that you would want to take the water from as high up in the box as possible to ensure that there is as little sediment as possible drawn into the system.

 

And as you say, its also quite possable the pipe isnt threaded. The hose my just be pushed on over the steelwork and secured with a jubileeclip.

- In which case you may have to cut a thread some how...

 

- However the easyest thing might be to get a lenght of pipe with the thread already cut at one end, and weld that into the mudbox, or the exsisting pipe?

 

I would think that a plumber could lend me a die to thread the end. I would think that it would be a standard sized pipe

Whens the boat next do for blacking??

Daniel

 

Very soon. I could wait for that. There are some other odd bits of welding that I need as well.

 

Nick

Edited January 29, 2007 by Theo