I understand that the term Scuttlehole was used in pioneer times for the hole that was used to access the attic of the home. Perhaps you had to scuttle (scurry) to get up there. It was also used to refer to the a small hole with a movable lid on the deck or hull of a ship.
A scuttle could also be a metal pan for carrying coals, or a shallow open basket for carrying vegetables, flowers or grain.
The scuttleholes still to be found in our area, though, are none-of-the-above. They are geological formations on the Moira River.
Some details are available on a website I prepared for one of my listings -