Best V hull

Hi, I think Sunseeker has pretty much the same deadrise as the other boats you mention. It differs from model to model and most modern boats are between 18 and 24 degrees aft. I can not understand why it should give less volume, but perhaps some deep V hulls are more narrow.

The idea of deep V has more to do with the weight of the boat and the speed you are cruising. A light and fast boat needs a deeper V for a softer ride.

As with many questions asked on here, there is not a singular correct answer. The term 'deep V' itself can be applied to a myriad of yacht types, from the archetypal fast powerboat right up through to very large yachts that blend a 'deep V' deadrise with a 'round bilge' form into a hybrid that displays some of the qualities of both hull forms.

Generally speaking, the faster and lighter the design, the narrower the chine beam as a ratio of its waterline length and the steeper the deadrise angle. There are many successful exceptions to this. Generally speaking again, most deep V hulls are designed so that the chine aft is immersed when the yacht is at rest. I'm not aware of many successful exceptions to this. From midships aft, there are varying designs that either carry the same deadrise angle all the way aft to the transom, or warp the deadrise angle to become far shallower at the transom. From midships forward, again designs vary from deadrises that steepen considerably as they move forward, to ones that carry on fairly flat toward the bow.

The issue as to which designs are better than others is mainly down to the specific application...the requirement for highest top planing speed, rather than maximum low speed endurance for example, or the ability to carry high load yet still plane at cruising speed etc etc. The overall design and layout may result in a LCG that is too far forward to make a constant deadrise design plane efficiently, without fuller deadrise sections at the fwd end...conversely, the maximum speed required may necessitate the LCB to be so far aft, that the fwd deadrise sections have to be steepened, not just for design efficiency, but to lose bouyancy to balance the design too.

As to interior space, assuming the lower accommodation flats are on or near the static waterline, then the space below this available for tanks / equipment etc is generally greater on a deeper V hull than a shallower V hull....other than that, the sole widths fwd on a deeper V hull are generally narrower than on a shallower V hull. Swings and roundabouts really, but the choices made in initial design have to cater for all the above and far more, depending on what the builder is taking to market.

I checked and the present Azimut 43´ has 14° aft and 21° amidships they say. Previous model had 19° aft, but as CODOG is saying, many boats today have a warped V-shape giving less deep V aft.

Our 40-footer has 22° aft and 45° at the bowthruster, our 32-footer has 25° aft and 60° at the bowthruster and our 25´is about 26° all the way...

The Camargue 44 is an example of a hull design with a cranked aft deadrise. The deadrise is steeper from the keel to the outboard edge of the outboard spray rail, than it is between outboard sprayrail and chine. For this particular hull, the designer decided it offers good load carrying characteristics at lower speeds combined with good tracking and sea keeping at higher speeds, more so than a constant and shallower aft deadrise for this particular application.
On other marques with similar overall dimensions, the designers may be using similar main design criteria, but be faced with different LCG, chine loadings, engine and transmission layout etc etc ad infinitum. Again, there is no single best hull form for any particular type or size of boat...the final hull design is optimised for the specific weight / power / speed etc. These variables increase yet further when its for a series production yacht, with many engine / layout / owners gear options available for one model.

(following is fictitious, NOT applicable to any marque or type )
Once upon a time, there was a hull design for a 50 foot boat.
It boasted a 22 degree deadrise, LCG 35% of static waterline, narrow beam, the sharpest of bows, and a power to weight ratio to die for.
It was begging for a gas turbine or two, driving surface drives. It promised almost raceboat performance, and it was signed off, eagerly awaiting its transformation from pure lines on a page, to a living reality.
But suddenly, something strange happened. The gas turbines were deleted, and two massive diesels were specced in their place. The surface drives were also crossed off, and substituted with submerged props in semi-tunnels. The fuel tanks were doubled in size, a crew cabin was added, and the fwd cabin was expanded far wider than the narrow hull could manage. A tender was thrown in, crates of additional equipment were thrown down the engine hatch. A ton of gyroscopic stabilisation was added as a nod to the customers who dont like boats doing what boats do. Marble, glass and solid walnut started to spread their mass throughout.
The poor design cried out for a few extra feet of length to counter its expanding beam, but was denied. Its svelte 22 degree deadrise expanded to 21, then 20, then, finally 19...its once arrow-like bow inflated to close on 45 degrees.
Finally, the design was complete and put into production. It bore only slight resemblance to its original concept, yet, by some strange quirk of market forces, the design lived to fulfil 80% of its potential owners, rather than the 20% it would have enjoyed had it stayed as it was in the beginning.

My web page is just that, one page and no more. But there is some more from me here at the Designers Forum; http://www.yachtforums.com/forums/yacht-renderings-plans-214/

The Gigayacht is just a 2D-rendering by the way, just like this one; http://img254.imageshack.us/img254/2161/bild83jb1.png