If all the world were only metric ...sigh. Since Renn's boat measurements use Imperial units not the metric system, I had a choice of either measuring the offsets in metric (a good idea) and later converting to the English system for cross-checking against his data ...OR... measuring everything in the English system directly, which is harder and still requires some conversion work but is much quicker and easier when taking and writing offsets directly from the boat.

When developing a table of offsets for a boat, there are a LOT of measurements coming off the boat. If a fellow were to write in standard fractional notation, e.g. 1/8" instead of 0-0-1, he'd use up a lot of extra room in his notes and more paper to boot. Rather than do that, a system that only uses a single digit of height for each row of numbers has been developed and is somewhat traditional in the boat design world. It's called the Feet-Inches-Eighths system.

In the Feet-Inches-Eighths system, every measurement is expressed as 3 numbers and a '+' sign if necessary. A trailing '+' implies "and a sixteenth". Some folks extend the system further in order to allow measurement to the 1/32nd inch level of accuracy. In that case, "+-" means "add a sixteenth minus a thirty second" ...in other words, just add 1/32". A "++" means "add a sixteenth and a thirty second", or just add 3/32". To illustrate, here are some examples:

• 1'3-1/2" becomes 1-3-4 to mean 1 foot plus 3 inches plus 4 eighths of an inch
• 3/16" becomes 0-0-1+ to mean 1 eighth plus 1 sixteenth of an inch
• 49-5/32" becomes 4-1-1+- to mean 4 feet plus 1 inch plus 1 eighth plus 1 thirty second of an inch
• 49-3/8" becomes 4-1-3 to mean ...well, you get the picture

Once you get used to the system, especially if using a standard English tape measure, it quickly becomes second nature and a very fast way to write down the offsets. Later on, when incorporating the data into a spreadsheet or into a CAD system, you will need to convert the numbers into something more easily understood by the computer ...I chose decimal inches. Example: That last measurement above, the 4-1-3 is 49.375". This is much easier to work with once the conversion is done, but time consuming and difficult to do when actually measuring the boat. Oh well ...