Through hull or skin fitting measurements
I have been taught to measure the size of a male filling across the threads and a female fitting by internal diameter.
In the chandlers I picked up a marked 11/4” Male fitting but when I measured it it was 1 5/8’ and this difference was apparent on other fittings.
What am I missing here? I want to measure the skin fittings on the yacht and then buy them on line but how do I get the right size?