40-meter motoryacht with speed and stability?

You should read the interesting conversation going on right now about Westport under the thread "FLIBS yacht sales".
It is quite informative, and quite humorous as well at times

You'll probably find a lot of what you're looking for in a Westport 130'.
Several threads, including an expansive review on the boat will be found in the forums here. Along with a wealth of discussions, debates, and data.

A Westport 130 with 2 x 2735HP MTU's will cruise at 24 knots and has a top speed of 28 knots. It's a GRP semi-displacement.

Google Ermis2.

I would take a look at a Millenium, "The World is not Enough" does over 65 knots with the center turbine, and will do I believe around 45 knots tops on both engines. Needless to say it has the speed and then some, it is also very stable at slower speeds from what I've heard. It is new or fairly new and I believe for sale.....It is also a tri-deck motoryacht.......The Palmer Johnson around 150' tri-deck is very nice looking as well.

You can also look at Ermis 2 built in New Zealand. She's 124' with triple 16v4000's doing 55 knots

ermis2

Ermis 2 is a special yacht, but still as I’ve heard from somebody who was involved 1st hand with this boat that it is a big compromise. The boat is owned by a Greek and is used in the Aegean Sea. During the summer months there are catabolic winds which can build up sharp seas and the boat then cannot go fast and could be very uncomfortable.

I have a 25+ knots boat with a 2500+ miles range at 10 knots. I hardly travel at such high speeds, although my boat's hull is semi-displacement with a sharp entry and a round bilge keel, which makes her far superior to planning hulls in high seas. I’ve used several planning hulls prior to this and once the seas build up they are useless.

My humble opinion, if you want to travel long distance and the oceans you should not go for a planning hull if you are looking for a safe and comfortable boat.

I bet it would be uncomfortable, and smell bad too. Probably related to the Greek diet.

Catabolic: The metabolic breakdown of complex molecules into simpler ones, often resulting in a release of energy.

Marmot, be nice; there is nothing wrong with the Greek diet. In fact, I was on board Ermis in July for some work and they fed me very well.
I am sure while it may be thrilling to be on most vessels at wide open throttle, it doesn't do the boat good to stay at that speed for an extended period of time. However, your forward speed should increase as your fuel rapidly decreases. I'd like to hear from our experts on this.

Marmot thanks for correction, I've done a usual spell check prior posting my msg, which ended up with a wrong correction... It should be "katabatic" and not catabolic

It wasn't really a correction, I think we all knew what you meant. It was just too good a play on words to pass up.

Believe me when I tell you I will never make fun of someone's non-native use of the English language unless I can make the same joke in theirs and have it come out funny to them.

No worries, it made me smile as well..

Ermis2 is built to 2.2Gs vertical acceleration, which is twice the standard Germanischer Lloyd sets for commercial hulls, so I think it will be able to keep a sharp turn of speed in heavy weather. Of course everything is relative, and it will be up to the Captain as to what speeds it will run in big water, but this boat was built to go fast in rough water.

Jorge did you overhear any talk about speed in big water? How fast do you think it would run in 8-10s?

I had the good fortune to be briefly involved with new build project for a client a Canterie Arno Mangusta Leopard L46/05. First I got to attend sea trials of hull L46/01. Very impressive build quality and engineered Go Fast vessel. Performed superbly 3 x MTU 6000hp x 3 Kamewa achieving 36knots.

L47/05 currently on hold, 200ton with 3 x MTU 9000hp x 3 x Kamewa predicted 40knots plus but down side was had limited bunkering that reduced cruising range to 600nm.
During same period I also provided logistical support for '2008 Westport 40mt
(130') and worked to resolve several minor but critical issues. A quality and very strong yacht, good sea handling in heavy swells averaged 25knots @ 2100rpm.