Technology and Operations
This forum is for discussing technological & operational matters pertaining to U-boats.
Re: Fuel Tank Construction
Posted by:
Scott
()
Date: September 26, 2002 06:22PM
Jerry,
First I would like to talk to Rainer. Yes I am quoting from the survey done at Portsmouth Naval Shipyard shortly after the war in 1946.
I came by this book from my commander when I was in submarines. I was always talking about U-boats and such. When I got ready to leave the submarines service for surface craft my commander gave this book to me as a going away present.
Now on to the discussion about the fuel tanks onboard the type IXC submarines.
A portable hose connection has been fitted on one of the outboard normal fuel tanks to provide a means for pumping out the contents of the tank; no fitting, however, has been provided to permit the use of air in this regard although it was originally contemplated.
Conversion of six of the eight fuel ballast tanks to main ballast tanks is accomplished from inboard. All valves on the outboard vent lines, compensating lines and fuel lines are operated from inboard. Blank flanges are not usedon the main vent lines.
The transfer of fuel oil is accomplished through a manifold arrangement. Individual manifolds servicing two tanks are located inboard of the fuel ballast and outboard normal fuel tanks. The inboard fuel tanks and the variable ballast tank fitted for carrying fuel, however, have individual cut-outs. (Back-up valves are installed on all piping leading inboard from the outboard fuel tanks.) Two main fuel oil manifolds are located in the engine room. One acts as a cnetral fuel tank maniflod and the other acts as a main distrubting manifold. The latter receives oil from the tank manifold ans discharges it either directly to the gravity feed tanks, via a fuel oil meter, or via the lub oil transfer pump. Wire mesh strainers are situsted on the suction side of the mater and in the transfer piping leading directly to the gravity feed tank. A four-way cock is used on the connection to the feed tanks which lines up one tank for filling and at the same time lines up the other with the fuel oil service piping. A special test connection and a sampling connection are on the line leading to the feed tanks. A portable pipe can be used to by-pass the feed tanks so that oil can be led diectly to the service piping from the storage tanks.
Emergency pumping of fuel oil with the use of the hand cooling water pump is provided. A selector valve is fitted on both the suction and discharge sides of this pump to permit it to be used directly with the transfer piping.
The capacity of the gravity feed tanks is appreciably less than the capacity of clean fuel oil tanks on U.S. submarines. The tanks have overflow pipes, drainage lines ans sampling lines with standpipes (to detect water in the oil); all of these lines have leads to a small feul oil pump tank. One tank is used to furnish oil to the main fuel pumps while the other act as a settling tank. This operation is switched when the "service" tank is emptied and is refilled.
The layout of fittings and pumps in the service piping is for the most part similar to U.S. pracitce. The main difference lies in the provision of a fuel oil meter ands in the installation of a sampling line with a sight glass on the fuel pumps suction. The fuel oil is led from the gravity feed tank through the meter (or its by-pass) to either or both attached feed pumps from where it is delivered through a knife-edge filter to the individual cylinder fuel pumps. The attached feed pumps can be by-pass; also ,a pressure relief and a safety valve are fitted on the pump's discharge piping. All leak-off oil from the diesel engine as well as from the sampling lines leads to the fuel sump tank.
The fuel oil meter used is of particular interest. Inas much as the same type of meter is used fro other services.
A separate system is set up to service the Junkers compressor. Oil is fed by gravity from the gravity feed tank to a small Junkers service tank. A fuel pump then takes its suction from this tank to feed the Junkers. A by-pass is installed around the tank so that the Junkers fuel pump can take a suction direct from the diesel engine service piping.
From an overall standpoint the fuel oil system and stowage arrangement on the type IX-C do not provide for the continued reliability and safety of operation as well as is provided on the U.S. submarines. Much additional reliance on observations by operating personnel is required to insure that the engines do not receive oil contaminated with water. The possibility of leaving oil slicks through the medium of the compensating water system, altough not readily possible, is more probable with the German arrangement. Emergency and standby arrangements, although provided, require much additional time and work to be placed in operation than is reqiured on U.S. submarines.
Several details of the sytem, however, are of particular note. The fuel oil meters are an improvement over U.S. designs. The simple tank capacity measuring device requires little piping and at the same time indicates actual contents whereas the one on U.S. vessels gives approximate contents while using much additional piping. The small fuel oil sump tank that is used as a collecting agent from all relief valves, sampling lines, ect. is of mert. The salvage tank on U.S. submarines performs this fuction to a lesser degree.
First I would like to talk to Rainer. Yes I am quoting from the survey done at Portsmouth Naval Shipyard shortly after the war in 1946.
I came by this book from my commander when I was in submarines. I was always talking about U-boats and such. When I got ready to leave the submarines service for surface craft my commander gave this book to me as a going away present.
Now on to the discussion about the fuel tanks onboard the type IXC submarines.
A portable hose connection has been fitted on one of the outboard normal fuel tanks to provide a means for pumping out the contents of the tank; no fitting, however, has been provided to permit the use of air in this regard although it was originally contemplated.
Conversion of six of the eight fuel ballast tanks to main ballast tanks is accomplished from inboard. All valves on the outboard vent lines, compensating lines and fuel lines are operated from inboard. Blank flanges are not usedon the main vent lines.
The transfer of fuel oil is accomplished through a manifold arrangement. Individual manifolds servicing two tanks are located inboard of the fuel ballast and outboard normal fuel tanks. The inboard fuel tanks and the variable ballast tank fitted for carrying fuel, however, have individual cut-outs. (Back-up valves are installed on all piping leading inboard from the outboard fuel tanks.) Two main fuel oil manifolds are located in the engine room. One acts as a cnetral fuel tank maniflod and the other acts as a main distrubting manifold. The latter receives oil from the tank manifold ans discharges it either directly to the gravity feed tanks, via a fuel oil meter, or via the lub oil transfer pump. Wire mesh strainers are situsted on the suction side of the mater and in the transfer piping leading directly to the gravity feed tank. A four-way cock is used on the connection to the feed tanks which lines up one tank for filling and at the same time lines up the other with the fuel oil service piping. A special test connection and a sampling connection are on the line leading to the feed tanks. A portable pipe can be used to by-pass the feed tanks so that oil can be led diectly to the service piping from the storage tanks.
Emergency pumping of fuel oil with the use of the hand cooling water pump is provided. A selector valve is fitted on both the suction and discharge sides of this pump to permit it to be used directly with the transfer piping.
The capacity of the gravity feed tanks is appreciably less than the capacity of clean fuel oil tanks on U.S. submarines. The tanks have overflow pipes, drainage lines ans sampling lines with standpipes (to detect water in the oil); all of these lines have leads to a small feul oil pump tank. One tank is used to furnish oil to the main fuel pumps while the other act as a settling tank. This operation is switched when the "service" tank is emptied and is refilled.
The layout of fittings and pumps in the service piping is for the most part similar to U.S. pracitce. The main difference lies in the provision of a fuel oil meter ands in the installation of a sampling line with a sight glass on the fuel pumps suction. The fuel oil is led from the gravity feed tank through the meter (or its by-pass) to either or both attached feed pumps from where it is delivered through a knife-edge filter to the individual cylinder fuel pumps. The attached feed pumps can be by-pass; also ,a pressure relief and a safety valve are fitted on the pump's discharge piping. All leak-off oil from the diesel engine as well as from the sampling lines leads to the fuel sump tank.
The fuel oil meter used is of particular interest. Inas much as the same type of meter is used fro other services.
A separate system is set up to service the Junkers compressor. Oil is fed by gravity from the gravity feed tank to a small Junkers service tank. A fuel pump then takes its suction from this tank to feed the Junkers. A by-pass is installed around the tank so that the Junkers fuel pump can take a suction direct from the diesel engine service piping.
From an overall standpoint the fuel oil system and stowage arrangement on the type IX-C do not provide for the continued reliability and safety of operation as well as is provided on the U.S. submarines. Much additional reliance on observations by operating personnel is required to insure that the engines do not receive oil contaminated with water. The possibility of leaving oil slicks through the medium of the compensating water system, altough not readily possible, is more probable with the German arrangement. Emergency and standby arrangements, although provided, require much additional time and work to be placed in operation than is reqiured on U.S. submarines.
Several details of the sytem, however, are of particular note. The fuel oil meters are an improvement over U.S. designs. The simple tank capacity measuring device requires little piping and at the same time indicates actual contents whereas the one on U.S. vessels gives approximate contents while using much additional piping. The small fuel oil sump tank that is used as a collecting agent from all relief valves, sampling lines, ect. is of mert. The salvage tank on U.S. submarines performs this fuction to a lesser degree.
