Gavin Atkin's OarMouse as a Day Boat

 Gavin's OarMouse is a V-bottom 14 foot row boat made from two 4' by 8' sheets of plywood... one person, fast and easy to build.

Overview of OarMouse plans by Gavin Atkin

Plans are free and available at Duckworks.

Using the plans, I built a concept model (scale 12:1) of a day boat based on OarMouse. 

The view above shows the 6' 3" (1905 mm) cockpit, 10' (3 m) oars, reverse reading compass, slatted floor boards that enable the foot brace and rowing seat to be adjusted to fit the rower, and the outriggers which are also adjustable and which provide a span of 5' (1524 mm).

Profile View: Why Windage is Not an Issue

No technical reason why the reverse transom other than I like the way it looks. And "Roci..." is a "hero" of one of my favorite science fiction series: The Expanse (James S. A. Corey). 

The Bow Transom Sloped Forward 30 Degrees

Fitted Out with Sleeping Tent 

Specifications of the Day Boat:

• LOA: 15' 6" (4.7 m)
• Beam: 3' (914 mm)
• Cockpit opening length 6' 3" (1905 mm)
• Cockpit width 1' 9" (533)
• Cockpit length (for sleeping) 7' (2.1 m)
• Water Line Length: 15' (4.6 m)
• Water Line Width: 30" (762 mm)
• WLL/WLW Ratio: 6:1
• Hull Speed: 5.2 knots, 9.6 kph, 6.0 mph

 Conversion of OarMouse to a Day Boat:

• Lengthened the LOA from 14' to 15' 6" (4.7 m) by re-spacing the stations to achieve a 15.5' length. 
• Slanted the aft transom forward by 30 degrees.
• Slanted the bow transom forward by 30 degrees. Note that these 3 changes were the only changes to the hull shape/size in the original plans.
  
  
• Made the two frames into two waterproof bulkheads 7' (2.1 m) apart providing generous flotation in the two end compartments.
• Surrounded the cockpit opening by 3" (76 mm) high coaming.
• Added a 4" (102 mm) V-shaped splash guard to the forward deck.
• Added a fairlead to the bow. See this article (at the end of the post) for how to anchor from the cockpit without crawling out on the fore deck.
• Provided outriggers. See this post for a description of these outriggers.
• Provided demountable hoops for supporting a shelter.

Summary-Pros: 

• A straight forward build from the free plans.
• She will be one of the fastest boats of all those in this blog.
• The full-decking, coaming and splash guard will result in a more sea-worthy boat than an open version of the hull. However, she is only designed for protected waters.
• Very low profile means she will be little affected by cross-winds when rowing.
• Plenty of storage space in the cockpit for supplies in waterproof bags. 
• Two waterproof compartments provide flotation.
• Long boats such as this can be car-topped.  See the comment by John Welsford at the end of this post.

Summary-Cons:

• The narrow V-bottom hull makes this boat tippy (but fast). Keep weight low and centered. See John Welsford's technique for reboarding long narrow boats such as this.
• No built-in waterproof storage.

This boat would be ideal for day trips in protected waters. A boat that moves through the water this easily is a joy to row. 

Jim Michalak's Batto as an Oar Cruiser

 Batto was introduced in this post. Following is one possibility for converting her into an Oar Cruiser.

Batto the Oar Cruiser ("Camo") Camouflaged for Stealth Anchoring,

Camo's 'Shelter Hoops', Outriggers, Deck Hatches and Floor Boards

See this post for more information about the Outriggers. And this one  for shelters.

Bird's Eye View

 Reverse Sheer & 4" (102 mm) Coamings

Reason for the forward sloping transom (about 30 degrees from vertical) is purely a personal one... I like the way it looks. 

Bow-on, Showing Splash Guard and Dory-like Cross Section

Conversion to an Oar Cruiser:

• Reduced the height of the stem by 11" (279 mm) resulting in 10" (254 mm) freeboard at the bow.
• Made the width of the topsides at midships 18" (457 mm) resulting in 15" (381 mm) freeboard to the bottom of the cockpit coaming.
• Lowered top of the transom 5" (127 mm) resulting in 10" (254 mm) freeboard at the top of the transom.
• Drew a new sheer line (using a long batten) through these three points to produce the reverse sheer (lowering windage) on the topside panels.
• Both topside panels will fit within 48" (1219 mm) wide plywood but the bottom panel will have to come from one additional plywood sheet.
• Replaced the temporary frame at station #6 with a permanent bulkhead (crowned 2", 51 mm).
• Replace the temporary frame at station #12 with a permanent bulkhead at station #13 (crowned 2", 51 mm).
• Between these two bulkheads is the cockpit 7' (2134 mm) long.
• Added a foredeck 6' 3" (1905 mm) from stem to 14" (356 mm) aft of the bulkhead at station #6.
• Added an afterdeck 5' 11" (1803 mm) from top of the transom to 14" forward of station #13.
• Added side decks 9" (229 mm) wide at midships.
• Resulting cockpit opening is 4' 8" (1422 mm) by 2' 3" (686 mm).
• Cockpit opening is rimed by a 4" (102 mm) high coaming.
• Two hatches, 1' 10" by 1' 7" (559 mm by 483 mm) installed on the two decks to enable access to the fore and aft compartments.
• Added cross-slatted floorboards to provide adjustable attachment points for the rowing seat and foot braces.
• Added outriggers that provide a span of 48" (1219 mm), appropriate for 8' (2438 mm) oars.
• Add provision for a shelter (see shelters) for alternatives.
  
  

Specifications of "Camo":

• LOA: 17' 9" (5.4 m)
• Beam: 45" (1143 mm)
• Weight Est: 110 lbs (50 kg)
• WLL: 16' (4.9 m)
• WLW: 26" (660 mm)
• WLL/WLW Ratio: 7.4:1
• Hull Speed: 5.4 knots, 10 kph, 6.2 mph
  
  

Summary-Pros:

• High WLL:WLW ratio (7.4:1) make Batto one of the fastest Oar Cruisers. A builder's comments (Ray Schaefer): "Slick as snot. Fastest fixed seat I ever rowed. It's a pleasure to row into a good wind and make good progress."
• A cruising speed of 4.5 mph (7.2 kph) for ten 45" sessions per day results in 34 miles (54 km) a day cruising.
• Lowering the bow and stern, and increasing freeboard midships (a reverse sheer) reduces windage, adds freeboard in cockpit area and keeps the underwater lines as designed by Jim.
• Adding decks, coaming and splash guard to her dory-like cross section make her even more seaworthy.
• The two water-proof compartments provide storage as well as emergency flotation

Summary-Cons:

• The addition of decking and bulkheads adds approximately 20 pounds (9 kg) to her weight. Long narrow boats such as this can be car-topped by one person.
• Narrow hulls (at the bottom) like this are fast but the compromise is increased tenderness and limited room in cockpit.

 

A Casco Bay Overnighter:

She had launched near Falmouth (Massachusetts) and was heading for Popham Beach, about 23 miles (37 km) ENE. Wind was Force 1 out of the west. She went through the islands and was about 1/4 of the way to Popham when the wind backed around to the SE, and increased in strength. Within an hour, she was struggling to maintain an ENE course with Force 4-5 winds abeam. She had relaxed her strangle hold on the oars, which helped to relax her arms and back. She had changed 'gear' on the oars to give more power in her stroke. She timed the 'hard pulls' when she was in a trough. Progress was still slow. She tried changing course to east, but then her boat corkscrewed as each wave passed. She missed a couple of strokes, throwing her timing off.

She was tired. She decided to head NW, running before the wind, heading for the south end of Jewell Island where she could loop around behind the island and find a little cove to tuck into and anchor. The seas were building and she needed to be careful not to broach. She was able to control the forward way on her Oar Cruiser using just the oars by back stroking when the wave lifted the stern. She was aiming for the 800' (250 m) gap between Inner Green Island and Jewell.

As soon as she was through the gap, she headed NE and ducked in behind Jewell. On her chart, she saw the perfect spot a little less than a mile away. She rowed comfortably in the lee of Jewell, anchored in Cocktail Cove that gave her protection for a good night's sleep.

She thought, "I'll get an early start in the morning, before the wind picks up, and continue on to Popham Beach." And that's what she did.