It is not possible to laud highly enough the comfort and economy that active fin stabilizers provide to an ocean crossing vessel. The development of these for small vessels over the past 20 years has improved greatly and cost of production now appears to be falling.

In their ability to reduce roll there is no doubt, the manufacturer’s claims of up to 90% roll reduction have proven to be true when installation has been correctly undertaken. Not only does roll reduction improve comfort, it also improves vessel performance at sea, making for quick and economic passage times.

While we would always recommend their installation they are however still a major cost. An alternative are paravane stabilizers which are passive yet also very effective.

As we always have a mid ship arranged engine room this allows us to position the stabilizer actuators in the best possible position in the vessel for performance and have the required hydraulic circuit contained in one space.

Correct location in the hull is important for maximizing the efficiency of the stabilizers while underway; not just the fore and aft location but also the outboard location with the fin splayed at the optimum angle.  

Along with correct fin location is immersion; it is important that the fin is immersed at all times, not just for efficiency but also for presevation of the fin itself.

Wesmar stabilizer

Stabilizer manufacturers correctly consider and build the fin to be "sacrificial", it is designed to be easily torn off in the event striking an obstacle rather than cause damage to the hull structure. Natually good seamanship on the part of the crew will always prevent this eventuality.

When at sea it is important that the fin remains immersed while underway. If located in a vessel where it is allowed to break free of the water the fin will be subjected to sudden shocks on re-entry with massive pressure applied to the underside of the fin on impact. Over time the risk is that this will cause detachment of the fin from the stabilizer actuator shaft which relies to a certain extent on the "glued" grip of the foam in the inner core of the fin. This attachment has proven to be quite satisfactory in normal working conditions.

It is in shallow draft vessels where adequate immersion is difficult to achieve, the solution often being to have the fins in a less than ideal location tucked away under closer to the keel.

Wesmar stabilizer

The Watson range of vessels are designed to maximise the efficiency of the stabilizer fin by correct location in the vessel and angle of splay relative to the hull shape. Also the protection of the fin is considered by having the outside extremity well inside the belting and bottom edge well above the keel line 

Stabilizer actuater

The stabilizer foundations are welded into the hull structure and are of such strength, only achievable in steel construction, that they can withstand twice the force required to shear off the fin shafts without causing damage to the hull structure.

Last Updated (Sunday, 19 September 2010 04:55)