Let’s say you’ve got a fiberglass fishing boat a little over 50 feet. It’s 20 to 30 years old and well worn. Plus it’s got the beam that boats of that age were built with, about 15 feet — give or take.

A 53-foot seiner being sponsoned at Platypus Marine. The starboard sponson is in place and will be matched up with the port sponson. Platypus Marine photo.
To be competitive you need a bigger boat, certainly one with more hold capacity. But to build a new boat over 50 feet requires you to work with a classification society, which means the cost might be jacked up by $200,000, $250,000.

 On the other hand, you don’t really want a boat under 50 feet because you don’t think it will be as safe as a larger boat, but, again, you don’t know if you can handle the classification society cost for a boat over 50 feet.

 What to do?

 If it was a steel boat the answer is simple — sponson her. If you’re on the West Coast there are plenty of yards that do that. It’s the primary business at Fashion Blacksmith in Crescent City, Calif. It’s what that boatyard does day in and day out.

Sponsoning a fiberglass boat, however, is different. No one is doing it on a day-in and day-out basis. Basically you are building a one-off boat and the costs are extreme. Then again, the costs might be more affordable, at least if you can get the boat to Platypus Marine in Port Angeles, Wash.

Platypus Marine recently sponsoned a 53-foot seiner built at Delta Marine. This was not a one-off project. Platypus Marine built a permanent mold from which they can take port and starboard hulls and build a new wider hull around the existing boat.

Laminating new hull sections up in the molds and then matching them up with the existing hull can probably be done for about half the cost of a conventional fiberglass sponsoning job. And it also takes a lot less time.

 To see if the sponsoned hull sections at Platypus Marine can be matched up with your boat, give them a call — (360) 417-0709.