[MaxResolution]

Don't laugh. Someday I'll probably have to appease her actual owner.

[CaptEvan]

For your further bow study pleasure, presenting the M/V Bourbon Orca (aka Whiskey Whale), Norway's 2006 Ship of the Year.

Graphic Image-
http://www.ulsteingroup.com/kunder/u...shipdesign.itm

At Sea Video Clip-
http://www.youtube.com/watch?v=Mqcpe5au_7M

[Innomare]

Contrary to most of the posters above, I believe the axe bow is a revolutionary concept. There's a lot more to it than the vertical stemline.

Let's not forget that this hull form is for fast (planing) vessels and that it is absolutely superior in the area for which it was designed: going fast in rough waters. (I have seen tanktesting footage which prove this)

Whether this is what the average yacht owner is after, is another question. Without a strict time schedule - why would you want to go blasting through rough seas?
And would you make such styling & interior space concessions for a rough-water capability that you would be using maybe 1 day in the year?

The story is different in the off-shore industry for example, but I can see applications in the yachting world too (support vessel for a fast sailing yacht, shadow boats, etc.).

Then again, the Maryslim (VSV), White Rabbit and others prove that also in the yachting world, people are increasingly looking for specific seakeeping characteristics. One could even consider an Axe-bow yacht as a fast version of the expedition yacht.

Bruno

[YachtNews]

I believe the axe bow concept is not an entirely new one. While it may be revolutionary for modern shipping and pleasure craft i am pretty sure that those iron clads and warships of by-gone centuries featured axeish bows or rambows?

[Innomare]

Yachtluver, as an example: show me a linesplan for a ship where the deepest point is located at frame 0 (at the bow).

Looking at how slowly things evolve in ship design (what did we get in the 1900's: the bulbous bow and the hard chine hull), I would call this kind of new, superior (in its field) hullform revolutionary.

Not because of the deepest point at the bow, but because of the concept in its entirety, which clearly allows to go faster in rougher waters. Slamming for example - one of the biggest concerns in heavy weather - has become almost a non-issue for this type of boat.

Bruno

PS I am not in any way connected to either the inventor or Damen shipyards.

[CaptEvan]

Bruno,

Why would this design be limited to planing hulls? The video clip of the Bourbon Orca shows her running at 13 kts compared to the other vessel's 8kts, certainly not on plane.

Seems trawlers and expeditions could greatly benefit from this design if they could sacrifice some area in the bow.

Evan

[KCook]

Err, how do they control bow steering in big swell with such a deep bow?

Kelly

[CaptEvan]

Fully read the original study of this post to answer that question.

[Innomare]

Originally Posted by CaptEvan

Bruno,

Why would this design be limited to planing hulls? The video clip of the Bourbon Orca shows her running at 13 kts compared to the other vessel's 8kts, certainly not on plane.

Seems trawlers and expeditions could greatly benefit from this design if they could sacrifice some area in the bow.

Evan

Hi Evan, the Bourbon Orca has nothing to do with the Axe-bow concept. It's a completely different animal.

That said, it's possible that the Axe-bow also has merit for slower vessels, but that remains to be investigated. If you do the same design exercise - minimizing the vertical accelerations - for displacement vessels, maybe you come up with something like the Bourbon Orca?

Kelly, as far as I know,
1. they have quite sizeable rudders
2. outboard of the rudders are fixed fins (similar to the rudders)
3. the rudder actuators work faster

I know they have been investigating (or still are) the possible use of a bow rudder, but that's certainly not fitted on the 4 vessels produced so far (probably because it's not necessary).

Cheers,

Bruno

[KCook]

Thanks guys.

[YachtForum]

Note: I posted this in another thread, but thought it was applicable to this discussion as well...

In year's past, private yachts were quite a bit smaller then the behemoths being launched today. Most of them were destined for native waters, with only a few big enough (and brave enough) to cross the pond. Enter: Dockwise, but that’s another story.

As yachts have increased in size, so have our expectations. We want to travel far, but getting there isn’t always a pleasant trip. Recently, a few designs have bucked the aesthetic trend in favor of function, in search of a way to work with waves as opposed to fighting them. A most recent example of this would be the Craig Loomes designed Earthrace vessel and I’ll expand a little on this…

A conventional (flared) bow design attempts to displace oncoming waves. As a flared bow submerges into an oncoming wave, water is displaced outwards. This results in deceleration and vertical forces that add resistance to the hull’s forward motion. This also creates lift, raising the bow out of the water. As the wave passes, a trough follows and the hull looses lift and falls in search of buoyancy. This is called pitching and in extreme conditions it can be violent. Stabilizers can help reduce pitching, but only to a certain degree.

In contrast, piercing bows (aka: fine bows) favor silhouetting a wave, or submersion. By going “thru” a wave, as opposed to over them, deceleration and vertical forces are reduced. The result is far less pitching and ultimately… a smoother ride with more consistent speed. But… it’s a much wetter ride!

On yachts the size of yester-year, the amount of freeboard was simply not sufficient to overcome the drenching a fine-bow would create. But with the size of today’s super yachts, coupled with the trend toward high freeboard, expedition-like bows in recent years, a piercing hull form can produce better performance without the need to run windshield wipers 24/7!

[YachtNews]

Talking about Project Sigma, here is a very small sneak peak at her in the shed. It is almost like the sneak peak we first had with the Sunflower/Al Said.

http://entertainment.webshots.com/ph...65464144AvLRJI

[YachtNews]

Here are some slightly more clearer pics of the Sigma Project still wrapped up like a present.

http://entertainment.webshots.com/ph...65464144UDMzMX

[jelletuininga]

Hi there everyone,

I used to work for damen and heard a lot of information about the axe bow concept. To get it straightened out, here some of the public information:
the axe bow concept is intended for high speed vessels operating in high seas. The vertical, narrow and downward extended axe shaped bow doesn't only cut waves, but also smoothens out any vertical movements. It does not stop these movements, but decreases the accelerations, which causes a smoother ride. To decrease the spray, the wheelhouse is placed a bit more to the rear, and also a number of spray rails are mounted.
Towards the rear the vertical frames go into a flat horizontal box shape frame shape for creating a planing hull shape. The outwards placed twin or more propellor arrangement makes up for any steering problem causes by the axe shaped bow. The high speed also makes this less of a problem. On lower speeds the bow thruster may have to work a bit harder for moving the bow sideways.
Also to make things easier: the bow desing from the norwegian Ulstein is called the X bow, opposed to the Dutch Damen Axe bow...

[Norseman]

This also creates lift, raising the bow out of the water. As the wave passes, a trough follows and the hull looses lift and falls in search of buoyancy. This is called pitching and in extreme conditions it can be violent. Stabilizers can help reduce pitching, but only to a certain degree.

The increased buoyancy as the bow is pitching down was also the idea behind the famous "Clipper Bows" on the Tea Clippers.
They still look good hundreds of years later, but perhaps the pitching motion was a bit excessive..?