Perry Design Review: DynaFlyer 38

I took home the DynaFlyer video and watched it with my kids. What we seem to have here is a boat capable of raising all the standards for performance. The Melges 24 did a good job of kicking our expectations up a notch or two, and the success of this is measured in Melges wanna-bes. Now, before the Melges has even begun to cool off, we have the DynaFlyer with its three moving appendages.

Laying in bed one night, I was reduced to counting knots made good to weather to induce sleep. An old image came back to me: Bill Garden's Junebug design. It was a 19-foot sharpie cat ketch that could redefine slow. A long beat to weather in 20 knots would have been an honest challenge of both your patience and your seamanship. The port, inboard profile drawings showed a man snoozing on a berth with a bottle cradled in his folded arms. It makes me ponder the reasons we are drawn to sailing.

If the objective attracts you, your credo has to be based upon VMG (velocity made good). Add a factor for how much effort it took to get those knots. Then take the cost of the boat and divide it by the boat's cost for knots per buck. This is a very fast 38-footer.

The key to the speed of this boat is the canting or pendulum-style keel. The ballast bulb is attached to a long arm that uses a hydraulic ram and arm to cant it up to 60 degrees to weather to increase the stability of the boat. This is tantamount to putting twelve 200-pound men on the rail of the 38. The fin above the bulb just holds the bulb on. The bulb is a squashed ellipse in section, but it appears to be symmetrical around the longitudinal axis in profile.

Lift is provided by the extremely high aspect ratio of the forward and aft rudders. This technology goes back to Gary Mull's 12-meter work in 1986. (Gary worked with Dr. Alberto Calderon on a tandem rudder system for a 12-meter.) The rudders taper from an 18-percent foil at the root to a 12-percent foil at the tip. The stocks are stainless steel. Each rudder is 6 feet, 10 inches deep and less than 9 inches wide at max chord. Unique kelp cutters travel down the upper 24 inches of each rudder. Kelp caught below 24 inches will have to be removed with a stick. That's a lot of fun. Kelp on the ballast fin will also require a stick. We may be looking at the KelpCatcher 38.

The designers of record for this interesting boat are Bill Burns and Matt Brown. The hull is a modified Hobie 33, with 5 feet, 8 inches added to the stern. The D/L of this design is 63.59. Beam is a convenient 8 feet for trailering. The bulb and rudders stay in place for trailering.

The SA/D is 32.4 without roach area. If I add the roach area of the main, the SA/D increases to 37.53. In this case the roach accounts for 23 percent of the mainsail area. We need to take roach area into consideration as more mainsail shapes approach elliptical plan form.

Approaches to improving performance are making racing boats increasingly exotic and radical. Water ballast is almost passé and now used in small trailerable cruisers. Bowsprits and asymmetrical chutes aren't even new anymore. We all accept ultralight weight as the foundation for any boat speed quest. Now, with the DynaFlyer 38, we need to start getting used to three moving appendages.

Boat Specifications