RADICAL New Hull Design...

A 70metre concept produced for an Aussie client. The design proposes a float-in-tender dock which can be used as a swimming pool, with bomb doors / a central atrium thru 4 decks / expansive use of glass / curvaceous styling which is integral to the structural elements as well as being aesthetic.

This design pushes the envelope in regard to concept and styling for new Superyacht proposals, and doesnt try to adhere to any rules so the creative objective could be realised.

SABDES - www.sabdes.com

SABDES 70

The hullform for the SABDES 70 is a planing monohull form, though along the way we did develop an original idea for a hull which morphs a monohull with cat-pods aft as seen in attache piccy; the purpose so the float-in-dock would be open all the time without need to flood. The wavepiercer hullform didnt suit the concept ideas correctly, though there is a trimaran hull seen on the NWBS yachts 61m E-motion was considered ok.

SABDES 70

... we had quite a bit of interest from UAE customers, but as yet the vessel hasnt been built. International Shipyards Ancona have also been interested.

... anything will plane if it goes fast enough... maybe, as the song goes... 'with a little bit of help from my gasturbines'.

Here are a few more renderings of that particular hull, and the original BIC pen concept development sketch. Should be somewhat self explanatory looking at the images; The design idea we termed the 'aqua hull' evolved for the need to have a 'float-in-dock' that allows guest tenders to enter, but without the need to keep flooding and draining the dry dock... also the trim and stability remains the same if it always is open to the water. The morph takes place at the chine underwater, so the hull looks completely like a nomal monohull except from aft. The keel of each pod is off centre (outboard) making the deepest part of the pod as far outboard as possible to also increase stability. Vee sections at the morph point, and a tapering flat run as it goes aft, allow the pods to still provide lift. A trim-tab could be configured to deflect spray away from the dock bay. Tenders could be stored port and starboard and lowered to the centreline of the vessel, this further reducing change of trim, as seen on most Superyachts today where the boats are sent outboard. Hope that explains it more clearly... we dont have all the answers yet, as it was just an idea and we reverted to a more conventional hull for the SABDES 70.. However, when I was a kid I saw a 15' plywood model (in 1982) of a wavepiercer cat in Hobart, with an extended shaft on its Johnson motor so it could reach the water... that was the start of Incat wavepiercers. SABDES

Thanks for the positive review... its great to hear your comments are reinforcing the whole ideas behind the hull shape which would also provide good at-anchor stability due the triangulated footprint, ie:main hull and 2 sponsons. The achievable speeds of the hull form would need full tank testing, which hasnt been done as yet, before deciding what its operational best would be. A semi-displacement speed range (18-25knots for 50m/165' hull) may be its best category, with improved fuel efficiency achievements; it would make a strong alternative to a traditional mono-hull, with some of the advantages (but none of the, debatable!, aesthetic issues) of using a tri of cat hull, for a Superyacht. To achieve high speed 30+knots, it may also work with a T-foil fwd, or hydro foil fwd, to provide some extra lift, and a flat plane between the sponsons aft... I agree the interaction of the sponsons would need looking at the results. As they are shown they are made wider than the monohull to increase stability, and could be made less. The approx ratio lengthwise of monohull is 75%, to the cat sponsons about 25%, thus keeping good inherent stability. The design lends itself well to waterjet propulsion. The 70metre SABDES design, we realistically proposed twin 6000hp diesel engines driving CPP to provide speeds in the range of 25+ knots... and a booster gas turbine for anything 35+ range for the non-wimps out there!
... shake rattle and roll... SABDES

shaken not stirred

On the question of propulsion for this type of hull, and since the concept behind the SABDES 70 (which we termed 'Sleek Princess'), is an attempt to create excitement for the guests 'yachting' experience, and also technical innovations like the hull design, then the propulsion might suit using a 360degree pod propulsion system like ABB have in their Compact Azipod product (see image). The hull form seems to lend itself to semi-displacement, as does the podded propulsion system. For higher speeds, 25+knots, the surface drive system would be a good option, noting your comments that waterjet propulsion would likely have intake aeration problems. The other advantage of using a podded electric propulsion system, is in allowing flexibilty for the location of the main generators, and increased manouverability, and having the props of the pods deep enough so as to avoid any aeration problems. To complement the innovations of the hull and propulsion system, why not also look at Fuel Cell System (like Ballard) to provide the energy. .. All possible and current technologies.. like James Bond! ... - SABDES

Thanks Donald for your review and sound advice. I agree with all your points, particularly that the main hull buttock shapes need refining.

In the interest of achieving a monohedron hull form, one proposal could be as per the new image I attach; At speeds <20kn the mainhull acts as a displacement hull, but as speeds increase >20kn + the addition of chine flats and running strakes aid lift. At the point where the main hull buttocks begin to curve upward, the chine flats and strakes stop and a step in the hull is added. The aft part of the main hull would lose resistance due to being recessed, and the hullform then becomes a 3 point planing surface, ie: main hull and aft sponsons. Weight distribution woud be critical for the correct trim angle, and the effects of the rooster tail would need careful consideration.

The SABDES 70 hullform in our later versions reverted back to a standard monohedron form, as can be seen in the attached early concept study image from 3/4 aft. Note the transom seen underwater.

Marketing wise, the idea for the hull form was not so much to reinvent the wheel while achieving high speeds, but an attempt to find a solution to create a hull form allowing the 'float-in-dock' without the need for constant flooding and draining. (as seen for eg on Princess Mariana, and some Naval Vessels). I came from a Naval design background, which was my inspiration in developing ideas for a 'float-in-dock' for tender deployment on Superyachts.

AMELS - The STASH concept

Amels have been producing a design where they split the Monohull aft into a Catamaran. They call it 'the STASH concept' (Single to Twin Aft Ship Hull).
Their basic idea is again to create an inside harbour for large tenders. Benefits are the tenders are located at the centreline, and the dock does not have the need to flood. The STASH was developed over a period of one year by the Amels Design Department with special contribution by Dirk Degroote, and was presented at 'Project 2004' Amsterdam Nov 2004.