| Nobiskrug | 142.1M | S/Y "A" | 2015/17 |

Why does she have retractable stabilizers? Some explorers have these (e.g., Ulysses), but seems unnecessary on a boat intended for Med and Caribbean.

Because they are huge and you don't want to crash them against the pier when you dock.
Eclipse, Octopus, Rising Sun, Solaris, Reverie, Azzam have retractable fins, it depends on the system you choose.

They can be much larger than those, that have to stay within the ships beam. And they are much more effective, because of their longer wingspan in relation to their cord lenght (aspect ratio). Because of their longer span, they do not have to deflect that much for the same stabilizing force, which in turn means, they do not produce as much induced drag and therefore cost less fuel. And if not needed due to calm sea or in harbour, they retract completely into their hull pockets, which means, no penalty and no danger of being damaged. They even come with trailing edge flaps and wing tip drag reducing hydronamical gymics.

I have the SKF (former B&V) retractable stabilizers on my present full displacement yacht. With the trailing edge flettner flaps and the pocket curtains, they are higly efficient, even at zero speed.

Makes perfect sense. Thanks, Maritina.

Thanks, HTMO9. Love the pic.

I was surprised very much, when I got the new SKF typ S stabilizer with the inflatable pocket curtains on my present boat, how effective and most of all how reliable they were. Even at 15 to 16 Kts, the flow noise, both when the Stabs are extended or retracted are down almost down to zero, as soon as the curtains are inflated. Plus growth in the pockets is minimized, because there is no light entering the pockets. An investment that pays of.

that's cool!!! the curtain is brilliant, it minimizes vortex and drag!

How reliable are those inflatable pockets? Prone to puncture?

My present inflatable curtains are now in their third season. No failures jet. They get normal service, when the boat is out of the water for the anual underwater cleaning. The bigger versions for cruise ships take much more stress, because these stabis are uge. My boat is much smaller, only 210 ft long. And I have only a pair of two stabilizers midships. The big boys use 4 of them. I will change them on condition.

Btw. they can easily changed by a diver within half an hour per side. For the big ones, one would need a crane and the ship to be in drydock. The inflatable curtains work fully automatic. If the extention of the stabis is selected, the curtains deflate, the stabilizers extend and the curtains inflate again, when the stabilizer is fully extended.

There is also a version from a different company with a solid pocket doors but this version needs much more maintenance and is causing more trouble. It is basically the same material, inflatable Zodiac MILPRO military commando boats are build from, just a little bit thicker.

But they definately will not survive an deliberate attack from a big swortfish or the mad Mr. P from R with his Bowie knife between his tees .

Now there is also a steel cover. It closes the fins up to 98%!

That is exactly the type of stabilizer, I was talking about. To complicated, to many moving metal parts, to many joints and bearings which need to be greased and serviced. Altogether much more sensitive to rust and growth. And the improvement in laminar flow along the pocket doors is negligible for a full displacement ship at hull speed.

I wonder why they have chosen two 'doors' instead of just one, you really don't need two. It's just...complicate things.
So...go back to the drawing board and do it right.

A new pic of SY A in Trieste

https://static.lsm.lv/media/2022/03/large/1/hhz2.jpg

Why are all these major yachts being reflagged all of a sudden? I thought they couldn't be reflagged while seized.

Done a few snaps of S/Y A about a week ago at Trieste anchorage.

Admin edit: Pics Attached

Nice shots Urbsey! Would you mind if we attach these pics to the thread so they are on YF's server? We don't like to use image hosting sites because the host can change the image, or leave an empty placeholder.