[joub]

Soapy water, clorox (1 cup per Gallon), a fairly stiff brush and a lot of elbow grease will usually do the job.

To keep it from coming back, you need a dry bilge, no topside leaks into the cabin and a flow of air through the boat when closed up.

If you are at a dock with power, there are some 110 AC units called Golden Rods (West Marine) that are very effective in controlling mildew.

Welcome to the joys of boat ownership!

Jim