Chesapeake Power Boat Symposium

This past weekend I was in Annapolis for the Chesapeake Power Boat Symposium. This was the 2nd of what looks like becoming a biennial event. With a good crowd in attendance and ample quality papers delivered, it looks like it has a great future as an occasion to educate oneself about developments in power boat design.

Held on the campus of St John's College in their lecture theatre, I had only one complaint about the proceedings. The number of papers on the schedule meant that each was squeezed into a 30 minute segment, including question time. Time pressure meant that most of the speakers had to rush their presentations somewhat to fit into the allotted time. It seemed to us in the audience that the 1 hour 45 minute lunch breaks could have been shortened considerably so that each speaker might have had another 5 minutes. That said, it is easy to question the decisions of an organising committee such as that needed for the symposium, without knowing the background to those decisions. On the whole they did an excellent job of putting a large number of technical papers in front of us.

The technical program kicked off with a tribute to Dr Daniel Savitsky, on whose research so much of current power boat performance prediction theory is based. It was an honour to see him there with his wife.

The papers covered a broad range of subjects. At one extreme were those that gave very technical results of research in various parts of the world, with complicated formulae that most will have trouble getting their heads around. At the other extreme were papers on more easily grasped subjects illustrated with video footage. These included radio controlled testing on the open sea of large scale models of military warships and the problems of tank-testing models of racing power boats that travel at speeds approaching 200mph.

An interesting paper was delivered by Paul Kamen on the dangers of current personal water craft (PWCs). This was with particular reference to the lack of brakes, in the form of a reversing bucket on the jet, and the fact that closing the throttle to kill thrust also kills steering. Trying to avoid a collision by closing the throttle and turning is generally totally ineffective and results in high-speed impact.

Another very interesting paper illustrated the wave patterns and associated drag of a monohull as it moves through water of various depths. What a surprise it was to hear and see that a hull has less drag in very shallow water than in slightly deeper water. In retrospect, it explained to me why I have noticed that my Paper Jet slips along effortlessly and with virtually no wake in calf-depth water.

Those of us in the audience who work with 3D surface design were delighted to see the presentation by Matt Sederberg on T-Splines. These are recently developed tools for NURBS surfaces that will make it much easier for us to define the often complicated surfaces of hulls and superstructures of boats. To cap it all, they also allow much smaller design files, for faster processing and smaller storage requirements.

All-in-all, the Chesapeake Power Boat Symposium was well worthwhile attending. I look forward the the 3rd one, in 2012.

Didi Mini Mk3

The new design is complete, aside from tying up a few loose ends. It is the Didi Mini Mk3, a very much updated version of the Didi Mini design that we have sold the past 10 years.

Introduced in the Didi Mini Mk3:-

~ Updated hull shape with broader stern and topside chine

~ Extended cabin roof, forming protected cuddy over front of cockpit
~ Easier access between cockpit and interior
~ More power from broader and flatter stern
~ Water ballast of fixed keel version further outboard
~ Bow and stern ballast tanks in canting keel version
~ Tacking daggerboard in canting keel version
~ Redesigned foam flotation, cleaner interior
~ Inboard chainplates for tighter genoa sheeting
~ Larger square-head mainsail

Overall, these changes produce a boat that will be more powerful, faster, more weatherly and more comfortable to sail.

The underbody of this hull was developed from that of the Didi Mini, with the same profile and bottom shape but blended into a topside chine that runs from forward of the mast through to the transom. Combined with a full-beam transom, it adds more power to allow more sail to be carried for greater speed. See more info and graphics on the Didi Mini Mk3 web page.

We will continue to sell the older Didi Mini design for as long as people want it and the kit suppliers will still be able to cut kits for it.

Work has also started on our next design, a cruising oriented Didi 28 design. It will be a bigger sister to the Didi 26, with many of the same features but with considerably more beam, headroom and space. Watch for that to emerge next month.

For our full design range, go to the Dudley Dix Yacht Design website.

Progress is being made

Earlier this month I hinted at the updated version of one of our popular designs that is soon to see the light of day. I said it would be a few weeks and that would make it about now, so I should update.

The work is progressing and most of the important stuff is done. The new hull shape is sorted out and most of the structural changes have been figured. Sail plan and accommodation changes also done. I decided to update a few other aspects of the boat at the same time, so those are on the go. I guess that about another two weeks will have it complete.

Winter weather has been good for doing design work outside of work hours, rather than freezing outside. The past few days have been warmer, relatively speaking. A SE gale blew for a couple of days and brought a 15ft swell up the coast. The storm was attached to a warm front, so today was around 60F (16C). I pulled out my boards and went surfing as soon as the wind went offshore to straighten out the swell. Nice surf of 7-8ft, maybe 10ft in the biggest sets. A SE swell along a North/South beach makes strong currents, so there was much paddling involved and much walking back along the beach occasionally to get back to the start point. With water temp below 40F (4C), even my full wetsuit with gloves, boots and hood did not prevent icecream headaches every time that I had to duck under a wave.

After a good afternoon of surf I am rejuvenated, feel alive and am back at the drawings. I must get this project done because the next one has already been lined up, a new radius chine plywood small cruiser/racer. Watch this space.

See our full range of designs at http://dixdesign.com/ .

Dudley