Why does a skin tank need baffles?

[BEngo]

It is also the case that most plant engines, as marinised for canal craft, are essentially designed to work in a near-stationary machine, so there is no motion-derived air flow as found in a moving  vehicle. Thus pumps are more effective and are designed to drive coolant through a fairly large radiator which may have been forced into a less than ideal location by the overall design of the machine.

All to our benefit really.

N

[nb Innisfree]

FWIW our LPW4 coolant pump coped very well with skin tank + 6 x 1 kW rads + a calorifier. 

Edited December 22, 2018 by nb Innisfree

[ditchcrawler]

20 hours ago, nicknorman said:

Air cooled engines have forced cooling “over the sides” ie typically an intake grill at one side and a shrouding over the engine with a fan that blows air directly over the engine fins and via ducting, out of the exit grill on the other side. Which is one of the reasons why they are so noisy - the engine is acoustically connected to the outside world via the cooling duct and grill.

My point was you still need to get the same amount of heat out of the engine room

[nicknorman]

2 hours ago, ditchcrawler said:

My point was you still need to get the same amount of heat out of the engine room

Sure but an installation designed for an air cooled engine does so directly (via the ducting to the outside) not via the general air space in the engine room. Whereas some kind of car radiator and fan thing would just dump the heat into the engine room and then, perhaps by means of some vents, eventually waft its way outside the boat, but not before it had made the engine room very hot!

[LadyG]

milk is pasteurised using the plate heater exchanger, the plates have a very large surface area, and they are ribbed ie ridged, essentially the most efficient flow is hot in one end, cold in t'other end.

 

To me "baffles" are barriers to stop liquids surging., as in fuel tankers doing an emergency stop.

I am no engineer, that must be klaar

Edited December 23, 2018 by LadyG

[bizzard]

Big tanker lorries when about half full surge back and forth a bit when stopping even though they have baffles. Watch them.

[alan_fincher]

19 hours ago, nicknorman said:

Sure but an installation designed for an air cooled engine does so directly (via the ducting to the outside) not via the general air space in the engine room. Whereas some kind of car radiator and fan thing would just dump the heat into the engine room and then, perhaps by means of some vents, eventually waft its way outside the boat, but not before it had made the engine room very hot!

It may not be an ideal arrangement, but you might be surprised just how many air cooled engines in narrow boats don't actually duct the hot air to outside, but dump it straight into the engine room.

 

Admittedly these engines were not designed to be used that way, but over the years many have lost the various ducting and trunking.

Both ours are like this - in an ideal world if replacement parts could easily be found, I'd reinstate pumping hot air to outside, but it's not trivial to get back to that state, unless you had bespoke cowlings made up to replicate originals.

 

As quite a few fuel boats have operated, loaded, and towing a loaded butty in this way, with no obvious ill effects, I take the view that mine running mostly "empty" will probably continue to not be too bad.

 

I'd not recommend it for an under floor installation, but in a generous engine room, with an openable pigeon box on the roof, and where side doors can be eft open, I don't think its as bad as it sounds.

The historic narrow boat "England" actually does have a water cooked engine, with the radiator in the engine room, (or at least it did before it was sold quite recently).  Even that arrangement seems to be OK, though I wouldn't want a water cooled engine that was cooled in that way.

1 hour ago, bizzard said:

Big tanker lorries when about half full surge back and forth a bit when stopping even though they have baffles. Watch them.

They are, I believe, never filled to the very top, unlike a skin tank.

[LadyG]

13 minutes ago, alan_fincher said:

It may not be an ideal arrangement, but you might be surprised just how many air cooled engines in narrow boats don't actually duct the hot air to outside, but dump it straight into the engine room.

 

Admittedly these engines were not designed to be used that way, but over the years many have lost the various ducting and trunking.

Both ours are like this - in an ideal world if replacement parts could easily be found, I'd reinstate pumping hot air to outside, but it's not trivial to get back to that state, unless you had bespoke cowlings made up to replicate originals.

 

As quite a few fuel boats have operated, loaded, and towing a loaded butty in this way, with no obvious ill effects, I take the view that mine running mostly "empty" will probably continue to not be too bad.

 

I'd not recommend it for an under floor installation, but in a generous engine room, with an openable pigeon box on the roof, and where side doors can be eft open, I don't think its as bad as it sounds.

The historic narrow boat "England" actually does have a water cooked engine, with the radiator in the engine room, (or at least it did before it was sold quite recently).  Even that arrangement seems to be OK, though I wouldn't want a water cooled engine that was cooled in that way.

They are, I believe, never filled to the very top, unlike a skin tank.

 

2 hours ago, bizzard said:

Big tanker lorries when about half full surge back and forth a bit when stopping even though they have baffles. Watch them.

I've seen milk tankers filled to overflow, [I was in the milk industry] It just came out through a sort of UFO vent at the top, the milk was being pumped in  at the bottom, but maybe the operator was havin' a fag.................. I assume fuel tankers are similar, though operators should not smoke, and technology may have moved on.

We used to use our tankers to transport water overnight to England in the "Big Drought". Very profitable.

Edited December 23, 2018 by LadyG

[bizzard]

4 minutes ago, LadyG said:

I'v seen milk tankers filled to overflow, [I was in the milk industry] It just came out through a sort of UFO vent at the top, the milk ws being pumped in obviously,  at the bottom, but maybe the operator was havin; a fag.................. I assume fuel tankers are similar, we used to use our tankers to transport water overnight to England in the "Big Drought". Very profitable.

I've seen milk tankers filled to overflow, [I was in the milk industry] It just came out through a sort of UFO vent at the top, the milk was being pumped in  at the bottom, but maybe the operator was havin' a fag.................. I assume fuel tankers are similar, though operators should not smoke, and technology may have moved on.

We used to use our tankers to transport water overnight to England in the "Big Drought". Very profitable.

Bumpy roads as well as the suns heat on the tanks can expand the fuel, water or milk to overflow from the top vents if too full. 

[LadyG]

15 minutes ago, bizzard said:

Bumpy roads as well as the suns heat on the tanks can expand the fuel, water or milk to overflow from the top vents if too full. 

Milk tankers are insulated, usually highly polished s/s, they would never be filled full unless being used to transport from depot to depot

Edited December 23, 2018 by LadyG

[David Mack]

3 hours ago, alan_fincher said:

It may not be an ideal arrangement, but you might be surprised just how many air cooled engines in narrow boats don't actually duct the hot air to outside, but dump it straight into the engine room.

 

Admittedly these engines were not designed to be used that way, but over the years many have lost the various ducting and trunking.

Both ours are like this - in an ideal world if replacement parts could easily be found, I'd reinstate pumping hot air to outside, but it's not trivial to get back to that state, unless you had bespoke cowlings made up to replicate originals.

 

As quite a few fuel boats have operated, loaded, and towing a loaded butty in this way, with no obvious ill effects, I take the view that mine running mostly "empty" will probably continue to not be too bad.

 

I'd not recommend it for an under floor installation, but in a generous engine room, with an openable pigeon box on the roof, and where side doors can be eft open, I don't think its as bad as it sounds.

 

Belfast has an air cooled engine in a separate engine room with the cooling air ducted out of a vent in the roof. But even so the engine room gets pretty warm. I wouldn't like to operate for any time without the ducting in place.

[Mike Tee]

How were the RN's / Nationals on working boats cooled? Did they have skin tanks back in the 'olden' days?

[NB Esk]

15 minutes ago, Mike Tee said:

How were the RN's / Nationals on working boats cooled? Did they have skin tanks back in the 'olden' days?

Mike, they were normally "raw water" cooled, where canal water was drawn through a rudimentary filter called a mud box.  I own an ex BWB tug with no fewer than 3 mud boxes.  One cools the air start donkey engine and circulates the water directly, the other two cool the main engine and gearbox and circulate through heat exchangers.  Hope this helps.....

 

 

[Mike Tee]

Yes, of course, I think I knew that - must have had a senior moment - can't confirm, 'cause I can't remember!!!