5/13/10

The 31-Plus Diesel Duck

 

The original 34 DUCK seemed the smallest the idea could be and work at all as at a semi-functional cruising boat. Sure, we've all seen smaller, but it just doesn't "work." The galley isn't quite big enough, the engine area is cramped, there isn't much headroom over the bunk, and forget storage. There isn't any. I've written a fair amount about the 34 and will refer youto the 34 spiel rather than repeating it all here!
Anyway, I got studying her after the plans were done and realized we could give her the "stepped" tranny without loosing any interior to speak of. Of course now there's even less deck space, but that's the compromise when you have such a small boat.
The original 34 was a plywood design but I think she can be steel too, so steel plans are being worked up. Steel makes sense these days.

 

Power is a 40 to 50 HP Kubota diesel although an 80 Deere is drawn in this view..These are strong little engines and well proven. She has a full width engine room, 6' long. Access to the engine can be from a door in the bulkhead in the aft cabin, a large hatch in the pilothouse sole, and another door behind the companionway ladder in the fwd. cabin. I would use the big hatch in the sole, and the door behind the companionway ladder.
This is the "biggest" DUCK for the length and is sorta pushing the "troller" idea but she's still a DUCK and I think would be a lot of fun for recreational use and coastal cruising. Yes, she could make passages but I personally would want to go bigger if I planned much of that. Not for safety, but for "elbow room!"

Here's all her "specs." As I said above, her basic numbers are the same as the 34 "Traditional."

 HYDROSTATIC CALCULATIONS
DIMENSIONS

LOA 33.32 ft
LWL 32.32 ft
Bmax 11.31 ft
BWL 11.00 ft
Dmax 4.47 ft
Volume 499.01 ft3
Displ. 31936.73 lb.

COEFFICIENTS
Prismatic 0.682
Block 0.314
Midships 0.461
Waterplane 0.794

RATIOS
L/B Ratio 2.94
D/L ratio 422
Lbs./In. 1505

CENTROIDS
LCB 16.86 ft (51.3% aft)
LCF 17.55 ft (53.4% aft)
VCB -1.12 ft

And here's how the computer say's she'll perform in FLAT conditions. Let me repeat that; FLAT CALM conditions! I quote "The Computer" frequently and recently read in a boat forum the comments from some Canadian character that my numbers not realistic at all. The thing is they aren't "my" numbers. I get them from a computer program that evolved into Autoship, which is more or less the industry standard. Supposedly it's calculations are based on the system used in "Skene's Elements." I use the same program for figuring the hydrostatics and offset table. I don't know about today but it used to be practically everybody in this bidness used the same program in their design work.

 DUCK 34 Estimated Power/Speed stuff FLATCalm Conditions: 

Figure one gallon diesel gives you about 18 HP an hour to get an idea of fuel usage in CALM conditions. Benno & Marlene cruise with their sails up, running the engine at a fast idle. Or, no engine in 15 knots, where the boat goes 4 knots.

V/L ... Knots ....Projected HP Required
1 ...... 5.69 ............. 4.8 HP
1.1 .... 6.26 .............7.4
1.25 ...7.1 .............. 15.8
1.3 .....7.4 .............. 21.5
1.35 ...7.68 ............ 29.2 HP

Back to Stock Plans

Back to HOME