YachtForums.Com - View Single Post

SAB · 03-25-2005, 07:47 AM

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.

03-25-2005, 07:47 AM	#18
SAB Registered User Join Date: Jul 2004 Location: Melbourne, Australia Posts: 22	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. Attached Images