Where is boat depth measured?

I have noticed some slight inconsistencies regarding published boat depths and actual measurements. I’m curious if all manufacturers measure the depth of the boat in the same place, and if so, where? Not really a major issue, just curious.

I’ve always considered it to be…

The max distance between the hull and the deck, usually at the front edge of the cockpit.

it varies
Usually it is at the front of the cockpit.

However, whether it is the inside measure (internal clearance) or outside (overall height) varies.

I’ve noted that Sea Kayaker Magazine will measure the inside height, but most manufacturers use overall (outside). This can be a difference of 1-2 inches.

Ain’t It A Pain?
I think giving both fore and aft deck heights by the coaming would be the most useful. But what I usually see is the fore deck height by the coaming. If I see over 10", I think it’s likely a tub relative to my size.


Traditionally, the depth of a hull is measured from the bottom of the hull to the gunnel exactly at midships. Because it’s measured at midship, it’s usually the minimum, or “least” depth of a hull.