Technology and Operations
This forum is for discussing technological & operational matters pertaining to U-boats.
Re: Fuel Tank Construction
Posted by:
Scott
()
Date: September 25, 2002 05:37PM
Jerry,
Here some information about the fuel oil stowage and equipment, I hope this will help in answering your question.
The fuel oil systems on the type IX-C have been set up to service two, comparatively slow speed diesel engines; the tank capacities are such as to provide a maximum crusing range of approximately 13,500 miles. The piping and pumping arrangements with the service and transfer systems are for the most part kept simple. Some additional emergency service is provided through use of numerous portable hose and pipe connections to other piping systems.
The IX-C can carry but a small percentage of its total fuel capacity in the normal fuel tanks. Four of the normal fuel tanks are outside of the pressure hull and four, of less capacity, are inboard. The remaining capacity is carried in the eight fuel ballast tanks and in the two variable ballast tanks fitted to carry fuel oil. In each case port and starboard tanks are considered as individual tanks.
A compensating water system is used with all feul carrying tanks with the exception of the auxiliary tanks. Pressure on the compensating system is through the medium of a head box in the superstructure. The compensating lines to the individual fuel ballast tanks run directly to the bottom of the tank while the line for the outboard normal fuel tanks leads into the small salt water niche (1.5% of fuel tank's volume) in the bottom of the tank; a line then leads from the top of the niche to the bottom of the fuel tank. The main compensating line to the inboard tanks feeds a distributing manifold that has individual lines running to the bottom of the tanks. Safety valves with leak-off to the bilge are on both the branch line to the manifold and the manifold. All tanks have the necessary inboard vents, backed up by two valves. Test piping with an overboard discharge leads from the bottom of all normal fuel tanks, and from a point approximately 4 inches above the top of the flood opening on the fuel ballast tanks. These test lines are normally used as salt water discharge lines when fueling, not only to indicate when the tank is filled with oil, but mainly to prevent possible contamination of the compensating water lines with fuel oil. All piping runs external to the pressure hull.
A simple, yet accurate, type of measuring arrangement is installed on one of the outboard and on both starboard inboard normal fuel tanks. Cocks is set to equalize the oil level in both the measuring line and the tank. Then changing the cock to the position permits draining off of the oil in the standpipe into a measruing glass, which when properly calibrated gives a true measrement of the oil within the tank.
The fuel piping arrangement on the variable ballast tanks that carry fuel are designed so that while removing all of the fuel oil from the tanks it is only necessary to compensate for half of the tank's capacity. The port and starboard tanks are interconnected; the oil suction line on the starboard tank is at the tank;s bottom while the line on the port side is about 3 1/2 inches above half tank capcity. On emptying half of the tank, water is then led in to again fill the tank; then the remaining oil is led off through the port suction line. A by-pass relief is on this piping to prevent excessive pressure being put on the transfer line; in addition, a small inboard venting connection is fitted so that excessive pressure can not get on the transfer piping ( because of leaky valves) when the variable ballast tank is used fro compensating purposes.
If you are not already bored I will continue tomorrow, if that is O.K. with all? I also have the inboard and outboard fuel tanks measuring arrangement if you like.
Here some information about the fuel oil stowage and equipment, I hope this will help in answering your question.
The fuel oil systems on the type IX-C have been set up to service two, comparatively slow speed diesel engines; the tank capacities are such as to provide a maximum crusing range of approximately 13,500 miles. The piping and pumping arrangements with the service and transfer systems are for the most part kept simple. Some additional emergency service is provided through use of numerous portable hose and pipe connections to other piping systems.
The IX-C can carry but a small percentage of its total fuel capacity in the normal fuel tanks. Four of the normal fuel tanks are outside of the pressure hull and four, of less capacity, are inboard. The remaining capacity is carried in the eight fuel ballast tanks and in the two variable ballast tanks fitted to carry fuel oil. In each case port and starboard tanks are considered as individual tanks.
A compensating water system is used with all feul carrying tanks with the exception of the auxiliary tanks. Pressure on the compensating system is through the medium of a head box in the superstructure. The compensating lines to the individual fuel ballast tanks run directly to the bottom of the tank while the line for the outboard normal fuel tanks leads into the small salt water niche (1.5% of fuel tank's volume) in the bottom of the tank; a line then leads from the top of the niche to the bottom of the fuel tank. The main compensating line to the inboard tanks feeds a distributing manifold that has individual lines running to the bottom of the tanks. Safety valves with leak-off to the bilge are on both the branch line to the manifold and the manifold. All tanks have the necessary inboard vents, backed up by two valves. Test piping with an overboard discharge leads from the bottom of all normal fuel tanks, and from a point approximately 4 inches above the top of the flood opening on the fuel ballast tanks. These test lines are normally used as salt water discharge lines when fueling, not only to indicate when the tank is filled with oil, but mainly to prevent possible contamination of the compensating water lines with fuel oil. All piping runs external to the pressure hull.
A simple, yet accurate, type of measuring arrangement is installed on one of the outboard and on both starboard inboard normal fuel tanks. Cocks is set to equalize the oil level in both the measuring line and the tank. Then changing the cock to the position permits draining off of the oil in the standpipe into a measruing glass, which when properly calibrated gives a true measrement of the oil within the tank.
The fuel piping arrangement on the variable ballast tanks that carry fuel are designed so that while removing all of the fuel oil from the tanks it is only necessary to compensate for half of the tank's capacity. The port and starboard tanks are interconnected; the oil suction line on the starboard tank is at the tank;s bottom while the line on the port side is about 3 1/2 inches above half tank capcity. On emptying half of the tank, water is then led in to again fill the tank; then the remaining oil is led off through the port suction line. A by-pass relief is on this piping to prevent excessive pressure being put on the transfer line; in addition, a small inboard venting connection is fitted so that excessive pressure can not get on the transfer piping ( because of leaky valves) when the variable ballast tank is used fro compensating purposes.
If you are not already bored I will continue tomorrow, if that is O.K. with all? I also have the inboard and outboard fuel tanks measuring arrangement if you like.
