A (Not So) Radical Oar Cruiser

A duck hunting boat, based on a 150-year-old design, as an Oar Cruiser for protected waters.

Sam Devlin's Mallard

The Sam Devlin design is based on the Barnegat Bay (New Jersey) Sneak-box. The big difference between Mallard and the Sneak-box is that the Sneak-box has the deck and the 'round' bottom meet at the sheer line and is carvel planked.

Mallard, on the other hand, is built with plywood, is V-bottomed and has narrow topsides (4-panel). However, though constructed differently, the overall design concept is very similar. The adaptation by Sam Devlin enables Mallard to be easily converted into a small Oar Cruiser for protected waters.
The design is quite capable of extended oar cruising: In 1876, Nathaniel Bishop rowed a Sneak-box (Centennial Republic) 2600 miles (4184 km) down the Ohio and Mississippi Rivers, sleeping aboard (under a wooden hatch) many nights. Bishop's book, Four Months in a Sneak-Box is available, free. It's an interesting book that includes maps, illustrations and the full narration of Bishop's voyage through 'Middle America' in the late 19^th century.

Plan Overview of the Centennial Republic

Details of the Centennial Republic

Note that Sneakboxes (15'/4.6 m) and Duck Boats (12'/3.7 m) are two class sail boats still being raced in Barnegat Bay (New Jersey), looking almost like they did 150 years ago.

Overview of Mallard plans

Mallard Specifications:

• Length: 12' 11" (3.9 m)
• Beam: 4' 10" (1473 mm), 8' (2.4 m) oars would be about right for the 4' 4" (1320 mm) span
• Weight: 155 pounds (70 kg)
• Water Line Length: 11' 0" (3.4 m)
• Water Line Width: 58" (1473 mm)
• WLL/WLW Ratio: 2.3:1
• Hull Speed: 4.4 knots, 8.2 kph, 5.1 mph

Commentary from Sam Devlin:

“This is an old and venerable design by now with the first design and boat built more than 20 years ago as I write this. She is of the “SneakBox” type of boat with the transom accommodating up to a 15 hp outboard motor, but she also rows or poles very well. In fact, of all the “SneakBox” types of boats that we design and build, the little Mallard is the best at rowing. There is positive foam 3 point flotation that allows the boat to float level and upright even if the cockpit were full of water.” 

Conversion to an Oar Cruiser:

• To reduce weight, I'd build with ¼" (6 mm) plywood, since I would not use an outboard.
• Reduce the width of the cockpit to about 20"-24" (508-609 mm) and reduce the length of the cockpit from approximately 7' (2134 mm) to 5' (1524 mm) so that only my feet would be under the fore or aft deck when sleeping.
• Make the coamings 4" (102 mm) high and raise the oarlocks at least a corresponding amount.
• Add a V-shaped splash guard to the deck just forward of the cockpit opening.
• Make the floor boards cross-slatted to provide flat sleeping area and anchors for the rowing seat and foot braces. Do not attempt to row for more than a few minutes sitting on the floorboards as in the photo above.
• Add a temporary shelter

Summary-Pros:

• Plenty of storage room for water-proof bags to hold supplies.
• Stable enough to stand up and fly-fish.
• Easy to row at slow speeds.
• Full decks and high coaming ensure safety in any rough water encountered in protected waters.
• Very low windage/profile.
• Ideal size and configuration for (stealthy) exploration of wilderness 'back-waters'.

Summary-Cons:

• Short waterline length and low WLL/WLW ratio (2.3:1) will make her slower than most Oar Cruisers. 
• Too heavy to car-top, but could fit in the back of a pick-up truck.