Checking oil level confusion.

[Mi_fiveo]

If I check my oil level on the trailer with the boat pretty much level it shows between the marks on the dipstick. If I check it when the boat is on the water, I’m over the full line because my boat sits very bow high in the water. The pic shows how far off level it sits in the water. Which is the correct way to check the oil level as there is probably a quart difference depending if it’s in the water or on a trailer?

 

[cptbill]

The engine should be level for a correct reading