Examples of wave piercing hulls, please?

Thanks for that link, quite interesting

 

That makes a big difference. The Spirit of Victoria was in Port Phillip Bay - in Victoria. not Sydney harbour in New South Wales.

It hit a big rogue wave on the run from Frankston to Melbourne, and there were three people injured and no deaths.

It wasnt a result of insufficient bouyancy, but of rapid deceleration from high speed.

The two designs were for totally different applications - one for the usually sheltered waters of Port Phillip Bay, the other for open water applications.

 

From Incat site:

Continual development over vessel generations has led Incat to design the centre bow to provide even more lift in the initial stages of wave encounter. The arch between the centre bow and the wavepiercer bows has been modified on later craft to obtain more freeboard and to have less flat surface.

 

I always recall the incident in Sydney harbour. But you may well be correct, as it was many years ago, and I no longer can find the news paper cutting.

The deceleration, you refer to is exactly this situation. There is no reserve buoyancy once the hulls become fully submerged at speed. The only limiting factor is the large buoyancy of the raft structure. That occurred much later and causes massive declaration.

 

You should put in the source, so the context can be investigated.

http://www.incat.com.au/domino/incat/incatweb.nsf/v-title/Centre Bow?OpenDocument

I'm not sure what point you are trying to make,

"Research projects conducted in conjunction with vessel owners enable constant product development from an informed and accurate standpoint. The R&D team aims to improve ship design and ‘buildability’ with the continual goal of weight reduction, plus research into ways to improve operational reliability, efficiency and economy.

Incat’s latest generation craft have a payload carrying capacity almost 100% of the ship’s own weight. The high payload to vessel ratio has not been achieved by any other builder in the global high-speed light craft industry. "

http://www.incat.com.au/domino/incat/incatweb.nsf/v-title/Design?OpenDocument

 

Of course. Rapid deceleration occurs on all types of vessels that encounter unexpected obstacles - waves in the case of hi-speed cats, hydrofoils and hovercraft, rocks and logs for jet boats, and containers for fast monohulls.

The only remedy is a good lookout, and quick reflexes by the pilot.

 

Call it Moses' hull.

 

How does the Classification Society treat the immersed hull portion as a measure? It is not LPP or LWL by definition of the rules.

 

DNV, oddly has it defined at the distance from the FP to the AP. And define the FP as:
FP=forward perpendicular is the perpendicular at the intersection of the fully loaded waterline (with the craft at rest) with the foreside of the stem
So one "could" elect to nominate an 'odd' location at the FP.

LR however, defines it as the distance from the stem (i.e. this is the most fwd part of the hull, underwater or otherwise, to the after side of stern or transom. Easy

 

Is it still thought to provide advantage though?

Seems a cheap means of increasing LWL in terms of mass..

Could someone provide a pro & cons list in a application such as a small passenger ferry or cruising power cat?

 

This is the idea I have of a "wave piercing". It is a central appendage, in a catamaran, breaking waves and distributes air sideways. It is neither a trimaran, nor a swath. Only applies to catamarans.
It tries to avoid not only the shock wave on the "wet deck" but the pressure of the compressed air on the hull.
The "wave piercing` "is not intended to increase the waterline length. It is not a reservation of buoyancy. It does not aim to advance the center of buoyancy. It does not create a wave train, as does the bulbous bow to reduce wave making resistance. It only breaks the wave and, perhaps, softens the pitch.
Note in the figure below the tunnels that cross both hulls to output backwash and air. This is an idea and registered trademark of the Spanish naval architect Enrique Lekuona

 

That's the one I have a vague recollection of, too.
We discussed this some time ago in:
http://www.boatdesign.net/forums/boat-design/wave-piercing-experience-31297.html

 

Hmmm..define ‘advantage’…that’s the hard part.
From a holistic point of viw yes, the marketing. Just read some of the comments on here and there is your evidence. The concept of “piercing a wave” has been embedded into people minds, it is neat simple, one can picture it (regardless whether it is correct or not). Thus the label has stuck. Ergo it is a successful bit of marketing. As for naval architecture, like everything else,…it depends!

If the boat is small, then it won’t make any real difference. It is more marketing than real science. If you start to go “larger”, you need to look at the SOR to decide is it worth it. The SOR shall dictate whether one wishes to pierce or not to pierce. However, any long slender high L/B ratio and L/D ratio hull form with the fore deck cut back is just the same, in terms of what benefits are perceived by others.

 

how about

"The Hales Trophy for the fastest transatlantic crossing by a passenger ship is not only a test of speed, but a test of endurance and reliability.

The past three Trophy winners, all built by Incat, each in turn earned the right to fly the prestigious Blue Riband. Since 1998, Cat-Link V (049) has held the Hales Trophy with a record of 41.284 knots."

http://www.incat.com.au/domino/incat/incatweb.nsf/v-title/Efficiency, Endurance & Speed?OpenDocument

 

Hard to argue with success I suppose- a bit harder to understand it though.