thru hull measurements?

[B Dobz]

What is the proper way to measure a thru hull fitting?outside of the threads,inside of the pipe?

[Greg Manning]

Generally any (metal) pipe is ID and any other "tubing"is OD.

[tg]

You can measure it any way you want. It depends what diameter you want where. If you want a 1" inside dia thru hull, make sure that's what you buy. A good supplier website like Groco shows drawings that clearly indicate hose ID dimensions, thread dimensions, etc. Groco also makes "full flow" fittings. Make sure you also know if the fitting's threads are NPT or NPS.