Stabilizers on planing yachts?

You must forget about the Hatteras. My 33 foot motorsailer will take me around the world in even better comfort. You must compare same size and speed if you like to compare.

In the 70-85 foot range of planing motoryachts, I think the Guy Couach will give you a better ride than most of the others if this is your major concern.

Sorry if I may sound a little harsh, but I will go to bed now at 03.am...

dear jade,

yes this is my cruising ground. due to the catabalic meltemi agean could be one of most disturbing crusing grounds, because you will have gusts coming over the islands anf these will create steep short waves and make it very uncomfortable if you are crusing agaist the wind. so, you cannot go fast and obliged to drop from the plane. at this speed if the stability does not become a problem, it is at least quite uncomfortable.

as to my hearings, the gyro system in ferretti does not effect the stabilty over 10-12 knots, it is more for swells at anchor.

however, you can always watch the weather and run away to a secluded anchorage with a fast boat and wait until conditions get better. the better solution would be a semi displacement hull with stablizers, which will give you a comfortable ride say at 14-16 knots even in disturbed weather.

Actually, there are quite a few planing and semi-planing yachts with trim tab stabilizer systems and they are very effective stabiliation systems when properly executed. However, I too am perplexed why a lot of the faster hard-chine hull design have no stabilization at all (because traditional fin stabilizers cannot be fitted) when the trim tab, or even active interceptors) solution would be of significant benefit.

Some background. Effective active trim tab stabilization systems have been around for about 16 years now. They were developed for high-speed ferries and there are probably 150 such installations runing around out there in the world...some in the 100m LOA range with trim tabs in excess of 14 square meters (each!). The Westport 105 monohulls that plied the Catalina Island route for many years were trim tab stabilized....the Wavemaster (Australia) monohull ferries are all trim-tab stabilized. Many of the systems achieved roll reductions in resonant beam-sea roll conditions in excess of 80%, and pitch reductions of up to 40% (something conventional fin stabilization system cannot/ do not do).

Overall, though, the yacht builders have been slow to pick up the technology, This is not really that unusual..all stabilization technologies for higher-speed vessels historically appear first in the ferry and military sector.

Just off the top of my head, I could count mybe 20 yachts that have trim tab stabilization systems in place. The most recent example is a planing 57' pilot cruiser, Franzen designed, that was at the Miami show. The Ray Hunt/New England Boat Works 'Vako Mano' (74'?) high-speed 'pilot' yacht is trim tab stabilized - and a good 'reference' for that type of solution since it is so effective that the owner insists it be 100% operable at all times. Several of Frank Mulder's designs are tab stabilized..a San Lorenzo I know of..a Destiny (that last two the 'Italian' type you referred to).

One 'problem' with trim tab systems is the fact that the tab assemblies must be custom designed for each hull they will be used on..trim tab stabilizers do not look anything like Bennet tabs. There are a few exceptions, like Quantum Archers, IF they fit 'your' hull..it's not a one-size fits all' kind of situation.

There are many misconceptions about how tab stabilizers effect the running and handling of a high-speed vessel...some restated further on in this thread. That is understandable since there are so few vessels out there that are sporting effective tab stabilization systems and thus opinions are often offerd up based on 'gut' rather than the experience of operating a vessel with such a system that is well executed. Their performance can be very impressive.

BMcF, let me quote myself in this matter. We all know there are systems in place and as you pointed out, most are used by professionals.

What scares me is when we get a question like today where a member is asking if he could run his yacht at WOT for hours. This is usually close to the highest speed the boat is designed for. Many also run on autopilot at high speeds, which is not to recommend without a lot of experience. If you further add active trimtabs into the equation, it takes a pro to be on top of what can take place.

If somebody is buying a yacht with all of these gadgets, put his route into the plotter and think the yacht will arrive smooth and safe to it´s destination without taking weather conditions in consideration, I am pretty sure we will see not only a broken wine-glass, but broken windows, arms and legs...

So, I will remain reluctant with "selling" too many of these tools, unless I know they will be handled by somebody who could handle the boat as well without them.

I'm not sure I completely follow your logic..in the sense that the exact same is true when fin stabilizers and other solutions are in place. Any boat can be driven beyond it's safe envelope, and if you are relying entirely on active stabilizers to do it - and they fail for any reason - then you can really be in the soup. SWATH vessels and some hydrofoils are famous for 'over the edge syndrome', where the vessels are so incredibyl capable that they are dirven beyond the point where even survivability becomes aquestion when a failure of either the stabilizers or propulsion renders the stabilization useless.

But..the flip side of that coin is that ANY properly-designed stabilization system is still providing a large benefit at speeds well below top speed..I.e. whatever is a safe speed for the prevailing conditions.

Agreed, and my point is the same as when some people think they can handle a Ferrari Enzo in all conditions, just beacuse they can afford to buy it, they will soon be in trouble. As we unfortunately have seen.

A couple anecdotes from very recent examples that illustrate both sides of the 'relying on the gadgets', coin:

1. US Navy X-craft 50+ knot slender 74m catamaran. While transiting from San Diego toward Alaskan waters last year, the ship suffered major hull structural damage, including buckled transverse bridge-deck frames and bottom plating separation (holed). What happened? 'Green' crew operating in a sea state and at speeds that were well above the certified operating limit of the vessel, but manageable with the extensive stabilization system that is installed on the craft. The system failed when a wet deck slam knocked out the gyro and the rest, as they say, was history. She was out of commission for 8 months for hull repairs in dry dock.

2. Nicely built custom 57' Pilot Cruiser with trim tab stabilization was making it's way on the outside, from Key West to Miami for the boat show, with a deadline to meet to get in to reserved show slip. Three very experienced captains on board, but none that had ever run a tab-stabilized vessel. Conditions became sloppy along about Key Largo area, with large waves on the beam, due the prevalence of several intense and fast-moving storm cells. However, operating at minimum planing speed of 18 knots and with the tab stabilizers tuned 'hot', the trip was almost boring and the captains on board became 'true believers' (a couple of 'turn the stabilizers on and then off' cycles was all it took). Now in that case, it is also true that conditions were never so bad that the vessel would have been in any jeopardy due a stabilizer failure, just darned uncomfortable, and there were numerous places to run smartly in-shore for sheltered conditions if things got too bad on the outside.