Is anyone familiar with the type boat? The boat belongs to a friend of mine and it has a plug for the hull and another for the motor bracket extention.
Bracket is designed to be run with the nylon plug in the bottom installed. Not sure what running it with the plug out would do - if anything. Seems to me air would prevent the bracket from filling up with water, but not sure. I would call a tech at armstrong at the web link provided above and ask them your question.