Cooling water plumbing, large GU boats?

[Timleech]

Anyone with intimate knowledge of the original plumbing of mud box, sea cocks etc on large GU boats, especially Northwich-built?

 

I've been generally tidying one up which seems fundamentally wrong.

The Mud box is plumbed in back to front (by my book), so the inlet comes in above the (missing) horizontal screen and the outlet is below. I had the sea cocks (plug cocks) off for servicing and annealed the copper pipework, it looked like a simple job at that stage to just turn the mud box around - there would be enough give in the pipes to do that.

WRONG. the inlet pipe flange is bigger than the outlet flange, it can't be reversed without swapping the brazed flanges round.

Another thing which seemed wrong in my book was the markings on the upper sea cock, the chisel line indicating the cock position was the reverse of 'normal', as well as being the reverse of that on the bottom cock. I've turned off the old mark and made a new one, but I wonder whether that was a mistake from 1936 or whenever or some sort of deliberate choice?

Regarding the mud box, I do wonder whether this one has been brought in from another boat. It looks remarkably like a Bolinders mud box, but I can't remember what the standard GU version looks like or whether it has a horizontal or vertical screen. Any helpful info welcomed.

The engine isn't original, but it's 'original style', I don't know the precise history.

 

Tim

[Chris Pink]

Not a large Northwich but a small Ricky National installation. No idea whether it is original but see no obvious indication that it is not.

 

Box has a vertical screen, the inlet and outlet both on one level, at the top which is more or less the outside water line (just below in fact) only one sea cock on the hull and considerably lower with the mark vertical if open.

 

Box is situated under drawer in the bench opposite the bed hole.

[Laurence Hogg]

Not a large Northwich but a small Ricky National installation. No idea whether it is original but see no obvious indication that it is not.

 

Box has a vertical screen, the inlet and outlet both on one level, at the top which is more or less the outside water line (just below in fact) only one sea cock on the hull and considerably lower with the mark vertical if open.

 

Box is situated under drawer in the bench opposite the bed hole.

 

The Ricky description is spot on as that was identical to my old boat Neptune which was original. The Town class fittings are on the starboard side on a H&W and you have two inlets for unloaded and loaded trim.

[Timleech]

The Ricky description is spot on as that was identical to my old boat Neptune which was original. The Town class fittings are on the starboard side on a H&W and you have two inlets for unloaded and loaded trim.

 

The Northwich sea cocks (inlets) are on the Port side, which actually makes a lot of sense from the point of view of minimising mud and silt collection but it does make the plumbing a bit more awkward. Nationals & RNs, and a lot of other engines, have the pumps on the Starboard side.

 

Tim

[soldthehouse]

Excuse my naivety but how does the cooling circuit work with regards maintaing an even temperature with this type of cooling and should I consider it when installing my "old engine" or not.. It isnt a reaaly old engine but certainly not a modern high revving thing.

[Timleech]

Excuse my naivety but how does the cooling circuit work with regards maintaing an even temperature with this type of cooling and should I consider it when installing my "old engine" or not.. It isnt a reaaly old engine but certainly not a modern high revving thing.

 

Usually, it relies on some degree of overcooling and the pump output being matched to the cooling requirement of the engine. That tends to be simple and reliable, but there is a loss of fuel efficiency and potential for increased wear through running too cool.

the next stage of sophistication is a manually controlled bypass, which requires keeping an eye on the temperature. Beyond that, some engines had a thermostatically controlled bypass.

 

Tim

[soldthehouse]

Usually, it relies on some degree of overcooling and the pump output being matched to the cooling requirement of the engine. That tends to be simple and reliable, but there is a loss of fuel efficiency and potential for increased wear through running too cool.

the next stage of sophistication is a manually controlled bypass, which requires keeping an eye on the temperature. Beyond that, some engines had a thermostatically controlled bypass.

 

Tim

Thanks Tim that makes sense, the Dorman engine Ive shown in another thread today had a manually controlled water flow in the circuit which I presume was for this very reason. I like the idea of juggling around with this till a pattern develops and would remove the ifs and buts of a skin tank, [as well as the extra fabrication]. what additional filtering is used in such set ups and is there any recognised source of info on these matters, Regards, Stuart

 

This is my engine its a Petter B4

 

Edited January 11, 2010 by soldthehouse

[c c]

The Mud box is plumbed in back to front (by my book), so the inlet comes in above the (missing) horizontal screen and the outlet is below.

 

Another thing which seemed wrong in my book was the markings on the upper sea cock, the chisel line indicating the cock position was the reverse of 'normal', as well as being the reverse of that on the bottom cock. I've turned off the old mark and made a new one, but I wonder whether that was a mistake from 1936 or whenever or some sort of deliberate choice?

 

The mud box in Badsey was installed with the refurbished National but I have no idea if is the original 1936 model. It is as you describe and I recently renewed my aquaintance with it after sliding through Leicester's mucky ditch of a canal. Stripped the mud box down at the canalside as the National was overheating for the first time in its life with no water circulating. The mud box is very heavy, has eight (I think) bolts holding the top on. Lifting off the top is a struggle. Then there are two gauze strainers one on top of the other which rest on a ledge allowing water to enter from above via the seacock - fall through the straining gauzes and on to the engine with the silt dropping to bottom of the box (drum). I used a kitchen ladle to lift out the muck and give it back to Leicester along with the Duvee and the two ropes around the prop.

 

The mark on the upper sea cock is also as you describe but I don't know what the lower one looks like as it is replaced with a modern rotary stop valve.

[Timleech]

The mud box in Badsey was installed with the refurbished National but I have no idea if is the original 1936 model. It is as you describe and I recently renewed my aquaintance with it after sliding through Leicester's mucky ditch of a canal. Stripped the mud box down at the canalside as the National was overheating for the first time in its life with no water circulating. The mud box is very heavy, has eight (I think) bolts holding the top on. Lifting off the top is a struggle. Then there are two gauze strainers one on top of the other which rest on a ledge allowing water to enter from above via the seacock - fall through the straining gauzes and on to the engine with the silt dropping to bottom of the box (drum). I used a kitchen ladle to lift out the muck and give it back to Leicester along with the Duvee and the two ropes around the prop.

 

The mark on the upper sea cock is also as you describe but I don't know what the lower one looks like as it is replaced with a modern rotary stop valve.

 

This is what seems fundamentally wrong to me, which is how the one here is plumbed.

In my book, the water should enter from below the screen, and exit above. That way, silt trapped by the screen will readily drop to the bottom of the box.

If the water passes down through the screen instead of up, most of the silt will be trapped forever on the screen.

 

Tim

[mykaskin]

I can only tell you about how Victoria's layout is - I've seen Nuneaton's, but not followed the pipes around enough to remember the path.

 

Victoria has an inlet on the starboard side, about 15 inches from the bottom of the boat. and below the water by about the same amount. A stopcock, and then a short pipe takes the water into a mudbox located about 6 inches below the inlet.

 

The mudbox has 6 or 8 nuts on studs holding down a cast iron lid, and underneath is a rubber gasket to provide a seal. The input water pipe comes into the side, and the outgoing pipe leaving at the top - but it sucks from the side at the top inside the box.

 

Inside the box there is an L shape piece of metal with the upright part full of holes, and the bottom section solid. Lifting this straight up and out will allow the dumping of accumulated mud back to whence it came. Often finer mud will get through, and so cleaning the rest of the box out is a good idea (this has to be done manually).

 

There are some flexible pipes, probably put in when the JP2 was installed, which head through the reduction/gearbox and then to the reciprocating pump on the starboard side of the engine. After that it goes through a directing valve which allows you to manually control the water-flow through the engine, or via a bypass. It then joins back up to go under the floor, and back up the port side to the water outlet.

 

Probably doesn't help you much, but there you go.

 

Nuneaton's setup is very complicated, mainly by an inlet in the bottom of the boat as well as in the side. Separate valves for flooding the ballast tank, and presumably some for emptying as well. All I know is that the intake regularly gets blocked even when running empty.

 

Cheers,

 

Mike

[BuckbyLocks]

Victoria has an inlet on the starboard side, about 15 inches from the bottom of the boat. and below the water by about the same amount. A stopcock, and then a short pipe takes the water into a mudbox located about 6 inches below the inlet.

 

The mudbox has 6 or 8 nuts on studs holding down a cast iron lid, and underneath is a rubber gasket to provide a seal. The input water pipe comes into the side, and the outgoing pipe leaving at the top - but it sucks from the side at the top inside the box.

 

There are some flexible pipes, probably put in when the JP2 was installed, which head through the reduction/gearbox and then to the reciprocating pump on the starboard side of the engine. After that it goes through a directing valve which allows you to manually control the water-flow through the engine, or via a bypass. It then joins back up to go under the floor, and back up the port side to the water outlet.

 

Mike

 

Only 4 nuts as I recall it Mike. I used to have to keep a spanner close by for emergencies. The strainer on the outside of the hull keeps the teabags and the sticklebacks out of the pump. (Both of which happened before the strainer was replaced.)

 

Correct on the plastic pipe. Mud Box is on the wrong side for the JP. The two cocks were removed at the same time and I donated them to the Boat Museum Boat Jumble a few years ago so can't look at the markers to see if they were different. I only ever used the lower one.

[c c]

This is what seems fundamentally wrong to me, which is how the one here is plumbed.

In my book, the water should enter from below the screen, and exit above. That way, silt trapped by the screen will readily drop to the bottom of the box.

If the water passes down through the screen instead of up, most of the silt will be trapped forever on the screen.

 

Tim

 

Now you've made me wonder! As soon as the ice melts I will have another look at it as your logic is sound

[mykaskin]

Only 4 nuts as I recall it Mike. I used to have to keep a spanner close by for emergencies. The strainer on the outside of the hull keeps the teabags and the sticklebacks out of the pump. (Both of which happened before the strainer was replaced.)

 

Correct on the plastic pipe. Mud Box is on the wrong side for the JP. The two cocks were removed at the same time and I donated them to the Boat Museum Boat Jumble a few years ago so can't look at the markers to see if they were different. I only ever used the lower one.

 

Yes, I don't know why I thought it had more. Looks exactly the same as Fulborne's.

 

Did Victoria originally have another water inlet? Where was it located in the hull?

 

Cheers,

 

Mike

[BuckbyLocks]

Yes, I don't know why I thought it had more. Looks exactly the same as Fulborne's.

 

Did Victoria originally have another water inlet? Where was it located in the hull?

 

Cheers,

 

Mike

 

Depends what you mean by original. She's had at least 4 engines to my knowledge. She was fitted with the standard National arrangement when the Kromhout was taken out, 2 cocks one above the other. The lower one was reused but with a new cock in 84. I can't now remember whether both were connected to the box when the JP went in in 74, but I think they must have been. We certainly didn't turn it round or anything like that, although I replaced the rubber seal a couple of times so that may have been replaced since. What I have no idea about is ehn the National was put in - it was taken out before the tender list of 62.

[Timleech]

Depends what you mean by original. She's had at least 4 engines to my knowledge. She was fitted with the standard National arrangement when the Kromhout was taken out, 2 cocks one above the other. The lower one was reused but with a new cock in 84. I can't now remember whether both were connected to the box when the JP went in in 74, but I think they must have been. We certainly didn't turn it round or anything like that, although I replaced the rubber seal a couple of times so that may have been replaced since. What I have no idea about is ehn the National was put in - it was taken out before the tender list of 62.

 

The only Northwich GU boat I have much experience of, still with watercooling, is the William. That's got a completely different arrangement with a single seacock, much further forward than on the ordinary large motors. AFAIK the water inlet is original from its Kromhout days, though the actual valve has been replaced.

I take it that the Victoria never had a Bolinder fitted?

 

Tim

[mykaskin]

The only Northwich GU boat I have much experience of, still with watercooling, is the William. That's got a completely different arrangement with a single seacock, much further forward than on the ordinary large motors. AFAIK the water inlet is original from its Kromhout days, though the actual valve has been replaced.

I take it that the Victoria never had a Bolinder fitted?

 

Tim

 

It seems the M1 was replaced with a national if Mike's comments are right, removed before going up for tender. I understand a two pot cold start bolinder was put in by ST Brant, and then Mike put the JP2 in when he got her in 1971.