One of the most important gauges on a boat is that which shows the fresh water capacity in the tanks, especially on a cruising boat at sea for long periods. The gauges on my schooner were very erratic and did not register accurately the amount of water in the twin hull-shaped tanks.
This article shows how new gauges were fitted that were custom-calibrated to the exact capacity in the tanks through the whole range.
2054 words 7 pictures. Price for this article $10
INSTALL AN ACCURATE FRESH WATER GAUGE