...into which you pour money." Well, that is one saying, but the hole I'm looking through is the opening in Kika's hull where stabilizers will be installed. The decision to add hydraulic roll stabilizers to our Selene was a big one for us. Cost was a consideration, but Gwen's view on this big expenditure is that stabilizers will increase our comfort and safety on the water, particularly as we get older....so better to spend the money now and get a better "return" on this upgrade instead of putting it off year after year.
Before getting started on this project, the yard had I choose to work with (http://www.latitudemarine.com) had to first remove the rolling chocks that had been added to the hull by the previous owner. The purpose the chokes or "bilge keels" as sometimes called, is to reduce roll in a beam sea by breaking the harmonic cycle of recurring waves; like when you move the flat of your palm through the water. Rolling chokes can help reduce roll but are no match for computer controlled active fin stabilizers.
Here, work has started on opening the hull for the stabilizer shafts to pass through from inside the engine room. A custom mold was made to create a solid 3-inch thick fiberglass "pad" unto which the Keypower stabilizer components will be fitted and bolted down. (http://www.kobelt.com/products/keypower). Additionally, these pads provide torsional reinforcement to the hull by reducing flex and absorbing new stresses on the hull being created by the large 7.5 square foot fins as they move in a seaway. Lou, the yard's fiberglass man will attach the pads to the interior hull by using new-age aircraft adhesive, then the mechanics will bolt together (like a sandwich) the stainless steel collars. The idea is for the Keypower dual-cylinder actuators to "float" on these collars while the fiberglass pads absorb the forces the forces produced by the fins.
Below are pictures of the main components of the Keypower-Kobelt stabilizer system; they include: hydraulic pump (here, mounted to our vessel's Twin Disk gear), control valves, hydraulic fluid reservoir tank, starboard and portside actuators, and the large heat exchanger that will cool the hydraulic fluid as it's pumped through the system. Two key components missing here is the digital control box (the stabilizer's brain) and a remote panel that will be mounted above the helm station in the pilothouse.
Pictured below, is one of the two large 7.5 sf. stabilizer fins that will rotate to commands processed in the digital controller. The controller anticipates how the boat will react to sea conditions and signals the actuators to rotate the fins in response to the ever changing sea state, creating positive and negative pressure around the fins that provide lift to counteract opposing forces while underway.
As if this project wasn't enough of a challenge, we decided to take advantage of the estimated 4-6-week haul-out to replace the original rudder with a specially fabricated articulating rudder. On our previous boat we had one of these amazing rudders, so it was an easy decision to have BEI build one for the Selene too. These rudders enable the skipper of a single engine trawler to perform close-quarters maneuvers that would be near impossible to make with a traditional rudder. By "thrusting" prop wash against the articulating flap on trailing edge of the rudder, it is possible to turn the boat in it's own length by pivoting the vessel off the stern without actually making way. Seeing is believing!
Soon after Kika was "splashed" we went for a short sea trial to make sure the new equipment was operating as expected. Thankfully, all the hydraulics associated with the Keypower roll stabilizer system did their job, and we had no leaking hoses! There wasn't much wind during our sea trail so hard to say how effective the stabilizers are, but we'll know soon enough. Unfortunately, the new rudder did have problems -- though maneuvering in our tight marina was greatly enhanced, the negative effect was a very "heavy" (hard to turn) wheel when turning hard to port or starboard at cruising speed. One solution is to add a power-assist pump to the hydraulic steering system, but that will require time and study to get right. The simple solution is to adjust the articulating wing on the rudder, reducing torque on the steering wheel by moving the pivot pin from position #2 to a less forceful, position #1. Oh! and our shipwright, Jake, made these nifty "line cutters" that he attached to the hull (picture bottom right). Their purpose is to protect the stabilizer fins and shafts from stray nets or rope that could catch on them.
We're Richard and Gwen (aka, Captain n' Cook), active boaters since moving to Seattle from Los Angeles in the early 90s. In that time we've owned several interesting vessels, but this blog will record our adventures on MV Kika, a Selene 47 Ocean Trawler.