USN WW2 practice of using seawater as ballast in fuel tanks

[Andy H]

Hi

When the RN started to takeover the DD's given by the USN as part of the Bases for Destroyers deal in 1940, they realised that the ex-USN ships had excessive roll, especially when the fuel was low. The USN combated this by using seawater as ballast. The RN initially feared such action, due to possible fuel contamination. Eventually (at least on these ships) the RN did use seawater as ballast.

Couple of questions:-

i. Was it 'Common' practice of for the USN surface vessels to use seawater as ballast?
ii. When and If the practice was stopped?
iii. What were the real chances of fuel contamination and how were they mitigated?

Regards

Andy H

[Natter]

I don't know any specifics in regards to USN practices, but the general practice of using seawater as ballast has been common in submarines (including modern vessels).
Submarine diesel engines had to be quite robust though (as it was always a chance to get seawater into the engines - both from the fuel and by the exhaust), so perhaps not a relevant comparision?

[mescal]

Hello Andy,

The use of seawter as ballast was theoretically standard practice (official instructions from BuShip) in the USN for all ships which had not a "sufficient" stability (can't remember the threshold, but from memory, all destroyer classes up to the Fletcher were concerned) when fuel was below a given level.

However, these instructions were often disregarded in parctice, most notably because it led to a large increase of work (bunker cleaning - to prevent contamination).

All of this is from memory.
A lot of information on this topic can be found in the inquiries following the loss of three destroyers in the typhoon Cobra because of insufficient stability.

[OpanaPointer]

"When do you use seawater for ballast?"

"When I'm scared enough to do that."

[ChristopherPerrien]

I am going to guess and say using sea-water as ballast is based on varying fleet SOP's and is ordered at the discretion of the captain, the practice seems common for US DD's in WWII when in need. However, During the Cobra(Halsey's) Typhoon , Dec1944, three US DD's were light on fuel and were lost, two of lost did not have sea-water ballast , one had partial, several other DD's who used Seawater ballast were not. It appears the two of the three, lost simply not have the time before conditions prevented them from being able to do so.


One other thing- I am not sure of what type of fuel US DD's used, bunker type fuel and/or diesel? However diesel being close to a "heavy fuel", I am guessing contamination might been handled the same way.-
Marine Diesels typically have a fairly heavy duty fuel -water separator, much more than land diesels. I am guessing though in super heavy seas, the separator may not have time to work if pumping requirements are too high, as they work on gravity, water settles to the bottom, diesel has a fairly high water content to begin with. Still , algae will grow indiesel and in diesel tanks , putting seawater in them only exacerbates this problem when you put diesel back in them, so extra cleaning is required, otherwise algae will soon funk up the whole system.

[OpanaPointer]

I don't know of a US destroyer that used diesel.

[Andy H]

Hi

This link is from another forum and Pg113 discusses Fuel Tank Emptying sequences, and it mentions the use of Diesel

http://archive.hnsa.org/doc/destroyer/steam/sec08.htm

Regards

Andy H

[Takao]

The diesels were used to provide critical systems with power in the event of a loss of main power. IIRC, the Fletchers had 4 auxiliary diesel engines, two for electrical systems, one for the pumps, and one for the blowers. Bunkerage was 739 tons of fuel oil and 26.5 tons of diesel.

[OpanaPointer]

The diesels were used to provide critical systems with power in the event of a loss of main power. IIRC, the Fletchers had 4 auxiliary diesel engines, two for electrical systems, one for the pumps, and one for the blowers. Bunkerage was 739 tons of fuel oil and 26.5 tons of diesel.

Oh, I know about the aux generators, I have babysat a few Cat 671s in my time. But I know there were warships with diesel engines, but not any DDs.

[Wellgunde]

I don't know any specifics in regards to USN practices, but the general practice of using seawater as ballast has been common in submarines (including modern vessels).
Submarine diesel engines had to be quite robust though (as it was always a chance to get seawater into the engines - both from the fuel and by the exhaust), so perhaps not a relevant comparision?

U.S. diesel electric submarines had what was known as a "fuel oil compensating system." As fuel was drawn from a fuel oil tank, the tank was automatically filled with sea water. This was done to maintain neutral buoyancy and to prevent the tank from collapsing at depth. The engine exhaust was routed up through the snorkel mast and released just under the ocean surface. We never had any problems with sea water contamination.

[Hoist40]

Don't know that much about WW2 practice but I was on a USN destroyer build in the early 1960's and we ballasted our fuel tanks when we were low on fuel and in rough weather. It was not standard practice but only done when needed. It was a lot of extra work, putting water in the tanks, making sure that no water was transferred to the Day tanks where the boilers got their fuel, and then emptying the water out before refueling.

From my limited reading on WW2 operations it sounds like ballasting was a similar cumbersome operation. For example refueling at sea is often something done at little notice when a refueling ship is available and it will interfere with that if you have to spend hours pumping seawater back into the ocean to empty your fuel tanks so you can then take on fuel

On the other hand todays Burke DDG-51 class has compensated fuel tanks which automatically take in sea water when fuel is used. When refueling the fuel displaces the sea water which is pushed out into the ocean

[OpanaPointer]

For example refueling at sea is often something done at little notice when a refueling ship is available and it will interfere with that if you have to spend hours pumping seawater back into the ocean to empty your fuel tanks so you can then take on fuel

I don't think "often" is the right word, "sometimes" would be better. DDs and other small boys were always concerned about where their next meal was coming from. Unrep and refueling were scheduled activities whenever possible. The cans who were operating with CVs and BBs could get a snack from the big guys, but if not they usually knew where/when to find an AO.

[Laurence Strong]

I have babysat a few Cat 671s in my time. But I know there were warships with diesel engines, but not any DDs.

GM make the Detroit Diesel 6-71 2 stroke engines......the comparable Caterpillar 4 stroke engine would be a 3204, 3408, or a 379......




Cheers
Larry

[OpanaPointer]

I have babysat a few Cat 671s in my time. But I know there were warships with diesel engines, but not any DDs.

GM make the Detroit Diesel 6-71 2 stroke engines......the comparable Caterpillar 4 stroke engine would be a 3204, 3408, or a 379......




Cheers
Larry

I didn't say I was a good babysitter.

[phylo_roadking]

Marine Diesels typically have a fairly heavy duty fuel -water separator, much more than land diesels. I am guessing though in super heavy seas, the separator may not have time to work if pumping requirements are too high, as they work on gravity, water settles to the bottom, diesel has a fairly high water content to begin with. Still , algae will grow indiesel and in diesel tanks , putting seawater in them only exacerbates this problem when you put diesel back in them, so extra cleaning is required, otherwise algae will soon funk up the whole system.

Concur with this; I'm sitting here with a chandler's catalogue on my desk, and there are six pages of hand filters, powered filters, separators, settlers, scrubbers, dispersants, disinfectants, additives, and mixers for dealing with this issue in modern pleasure boats!