Building a Butterfly Skylight

The skylight whose construction I will describe here originates with Murray Peterson, who gave the essence of simplicity and practicality to every yacht he designed, from its overall shape to details such as those found in this skylight. He developed the original one for the 39' double-ended ketch LILLE DANSKER, which was launched at Hodgdon Brothers in East Boothbay, Maine, in 1947.

As with the booby hatch that I wrote about in 2014 (see WB No. 238), this construction respects Peterson’s original work but has been updated with a couple of tweaks by his son, Bill, a yacht designer in South Bristol, Maine. The principal difference is that Bill called for using rectangular instead of round deadlights. Other than that, this is his father’s design.

A key element is that this skylight’s perimeter is square, and its rabbeted inside lower edges fit over a teak grub, or sill, that is fitted and fastened to the deck. As a result, this skylight can be detached, lifted off, rotated 90 degrees, and reset to catch the breeze regardless of its direction.