I bought some rope from wal-mart. and on the back of the package, it says that 3/8 inch dock line is good for up to a 28 ft boat. I have a 26 ft sailboat, and I will not use anything less than 1/2 inch 3 strand twist.
It seems like these guidelines are not right. maybe a 28 ft sailboat will tug more on the dock than a 28 ft powerboat.
I also use 1/2 inch anchor line.
What rule of thumb do you use for rope size?
I think 1/2 inch anchor line would hold up in a storm. 3/8 inch might break.