The only time anyone wants to know the exact length of a sailboat is if there’s a concern about it fitting in some space.
At all other times, your incentive is to make the biggest lie you can get away with.
If you carry a calculator in your pocket, but if you're just casually converting, 3 feet per meter is pretty good. 100 square meters is about 1000 square feet as well. Not legal for tax purposes, but good enough to understand how big a place is.
40 inches per meter is easy to remember and pretty accurate
how many inches per feet ?
12
12 inches per foot
3 feet per yard
1760 yards per mile
Or ten feet per three meters, since longer distances are rarely measured in inches anyhow.. The proverbial ten foot pole is 3048 mm long.