Bolger's Cartopper

Using the plans published in Bolger's book, Boats with an Open Mind (page 25), I built a model to illustrate how Cartopper could be converted to an Oar Cruiser without changing the hull shape.

Specifications

• Length: 11' 6" (3.5 m)
• Beam: 4' (1219 mm)
• Weight: 90 pounds (40.1 kg)
• WLL: 8' 11" (2.7 m)
• WLW: 29" (732 mm)
• WLL/WLW Ratio: 3.7:1
• Hull Speed: 4.0 knots, 7.4 kph, 4.6 mph

Overview

Rudder Controls

Rudder

This photo shows the floorboards in two sections so they can be removed from the sleeping compartment/cockpit that is approximately 7' (2.1 m) long (between waterproof bulkheads located where frames 1 and 3 are in the plans), with the cockpit opening of 4' (1.2 m). 3" (76 mm) high coamings are added to the fore and aft decks. The king and queen planks are Western Red Cedar with the decks mitered into the edges. Inwales are added to the cockpit sides to strengthen the topsides because frame #2 has been eliminated.

Bolger's Cartopper

In this view, the foot of the mast under the foredeck, butted up against the forward bulkhead, is locked into the maststep at the forward edge of the floorboards.

The Mik Storer style holstered rudder is controlled by a shockcord (on the port side ending in a jam cleat) and on the starboard side by a control line running forward to the inwale.

At the bottom of the rudder holster there is a horizontal plate that is at waterline level. This plate matches in size the plate on the bottom of the rudder blade. These two plates increase the efficiency of the rudder, regardless of how deep the rudder blade is immersed.

Bottom of the Rudder 'Holster'

The plate on the bottom of the holster needs to be extended to the back of the rudder blade, but still open at the back so that the blade can pivot back if grounded.

Rudder Assembly

Sailing

Downwind sailing is powered by a 14 square foot (1.3 sq. m) sail hoisted on an 8' (2.4 m) mast that is built in two 4' sections held together with a 1 & 3/4" ID (45 mm) Carbon Fiber Oar Ferrule. The two 4' sections and the sail can be rolled up and stored in the cockpit.

Cartopper with Downwind Sail

The sail is controlled by two sheets. The sheets run from the sail back to a dead eye, forward to a bollard and then to a jam cleat. The bollard idea came from a Yrvind post.

Sail Controls

To help control downwind tracking, a 2 & 3/4" (70 mm) deep full length skeg is added. The idea for this came from Clint Chase's Drake (see construction photos).

Full Length Skeg

Shelter

The 'tent' shelter is supported by the mast. The foot of the mast has a small 'lip' on the forward edge which hooks under the king plank on the forward edge of the mast slot. Headroom under the tent at the after end of the cockpit is 42" (1.1 m).

Mast as Shelter Support

The forward coaming is slightly relieved by a 1/2" (13 mm) to keep the mast from sliding side to side. Just forward of the coaming are two dead eyes to provide anchors for a tie down that holds the mast on the coaming. Note that the mast slot is closed by a plug, held in place by shock cord, while rowing (not shown here).

Hold-down for the Mast Used as Tent Support

Tent Shelter in Place

This view, looking aft, shows the bottom of the large waterproof access hatch (held with 2 black turnbuckles) in the bulkhead which provides not only flotation, but many cubic feet of storage space while cruising.

Cockpit Looking Aft to the Bulkhead  

This oar cruiser really appeals to me: Compact, pretty, and ideal for weekend cruising in waters that most other cruisers can't reach.