Hello Mr. Tore,
Reviewing Simon's piping drawing:
1. It looks like the 2 lube oil filters near the oil coolers are the strainer type filters which have always been in place.
2. The six (6) valves a, a1, and b on the valve chest look to be clustered in the center of the drawing.
3. What is the device at 8 o'clock (lower strainer) and 10 o'clock (upper strainer)?
4. The port and starboard water supply valves don't look to be air activated weed clearing?
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Regards,
Don_