A tender for a musical ark

by Laurie McGowan


The electric motorsailer EOS is meant to serve as the tender to a 22′ St. Ayles skiff—a 22′, four-oared rowboat—that has been adapted to make music in an attempt to communicate with whales.


Featured in Design Sketchbook from WoodenBoat Magazine: This is the 3-D concept drawing and design profile you can read in WB No. 271, November/December 2019.

SEPHIRA, the St. Ayles Skiff, nests between the mothership catamaran’s two hulls when not in use. EOS’s 16′ beam makes trailering a manageable proposition. Slender, easily driven hulls in a catamaran configuration offer both speed and stability. The “biplane” rig can be set wing-and-wing on a dead run.


  • LOA: 36′ (10.97m)
  • Maximum beam: 16′ (4.88m)
  • Beam of hulls: 4.28′ (1.07m)
    (10:1 LWL L/B ratio)
  • Draft: 2′ 10″ (0.88m)
  • Displacement: (1⁄2 load) 11,356 lbs
    (5.15 tons)
  • Sail area: 920 sq ft (85.47m2)
  • Power: Twin Thunderstruck 10kW @ 48V electric motors with 2:1 reduction
  • Batteries: 8 100 Ah LiFePO4 12V
  • Wind generator: 600W
  • Solar panels: 600W total
  • Fresh water: 60 gal. (114 liters)
  • Wastewater tanks: 60 gal. (114 liters)
  • Passenger capacity: 12 day passengers, 8 overnight

Short winged keels counter leeway and house the propeller shaft apertures. Wishbone booms minimize running rigging, and a headsail can be set between the masts.

EOS’s articulating aluminum ramp eases launching and retrieval operations. Basic accommodations include a galley, dinette, and head.

The boat, which displaces slightly more than 11,000 lbs, is driven by twin electric motors. At 12kW (about 16 hp) the boat makes 7.5 knots; 26.5kW (about 35 hp) yields 10 knots.

Laurie McGowan is a Nova Scotia–based boat designer with a diverse on- and below-water work history. He specializes in energy-efficient commercial and pleasure boats. More of his work may be found at mcgowanmarinedesign.com.

Do you have a boat concept you’d like to see Laurie McGowan develop on these pages? If so, send it to Sketchbook, WoodenBoat Publications, P.O. Box 78, Brooklin, ME 04616, or email it to sketchbook@woodenboat.com. Your letter should be no longer than 500 words.

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