One of the more difficult design issues is positioning the stabilizer fins. The considerations are as follows:
- Bottom of fins are above the bottom of the canoe body or keel when the fins are centered
- As close to the point of maximum beam as possible to maximize leverage
- Near the center of buoyancy to minimize steering impact
- As close to parallel with the surface as possible for better force vectors
- Sufficiently below the waterline to minimize loss of end plate effect in rough sea states
- Good access for inspection and maintenance
- Structural integrity to minimize hull damage in the event of a grounding
If you work through this list it will quickly become apparent that there are a few conflicts.
In the case of the FPB 97, the fin is a touch further forward than is optimal. However, this gets us access in the landing area between the forward owner’s suite and the guest accommodations, a location where you can quickly inspect the actuator mechanisms. The tip of the fins is above the canoe body bottom, and they are positioned deep enough so that ventilation in big seas should rarely be an issue.
The stabilizer shaft comes through a transverse frame, and there is a longitudinal girder reinforcing the hull to help dissipate impact loads when the boat runs aground, although with sub-five foot/ 1.5m draft, running aground should be a rare occurrence.