Friday, February 5, 2021

Michalak's "Marksbark", a Day Cruiser

 Jim's long, narrow "Marksbark" is a fast day cruiser that can carry a passenger safely and yet provide an invigorating single handed row with a hull speed of 5.4 knots. 

Marksbark as a Day Cruiser


The Safety Features of this Day Cruiser

  1. Water proof compartments at each end of the hull, approximately 2' (210 mm) long.
  2. The hull is fully decked except for the cockpit opening.
  3. A 3" (76 mm) coaming surrounds the cockpit opening. 
  4. The deck extends beyond the hull width by 8" (200 mm) midships and then becoming narrow fore and aft. Fastened to the bottom outside edge of the extended deck is a 2" (51 mm) wide 'plank' that runs the length of the hull on each side. Filling the space between this plank and the hull is 2" thick foam. This provides approximately 33 pounds (15 kg) of additional flotation on each side of the hull. Thanks to John Welsford for the idea of extending the deck beyond the hull as he did in his "Kiwi PDR".


    Underside of Deck Extension to Hold Foam Board Flotation 

 

The cockpit opening is long enough (7', 2.1 m) to accommodate rower and a passenger. Two positions for the oar locks enable a single rower or a rower with passenger without affecting trim. The cross-slotted floorboards enable the rowing seat and foot rest to be shifted as necessary.

Set-up for Rower and No Passenger

Added Passenger Seat & Moved Footrest/Rower's Seat Forward

Two storage compartments (in addition to the water proof compartments at the ends of the hull) provide  dry storage with access through deck hatches. The aft compartment is 2' (610 mm) long and the forward compartment, pictured below, is 3.5' (1069 mm) long. Both hatches are 12" x 18" (305 x 457 mm). The after hatch supports the reverse reading compass


Bow Showing Forward Storage Compartment, Anchor Cleat & Anchoring Fairlead

Use of the 'anchoring fairlead' (see end of post) enables anchoring without going on the deck, which is dangerous in a hull this narrow.

Specifications:

  • Length: 18' (5.5 m)
  • Beam: hull: 3' (0.9 m), edge of deck: 4' (1.2 m)
  • Water Line Length: 16' (4.9 m)

  • Cockpit length: 7.5' (2.3 m)
  • Cockpit opening: 7' by 2.5' midships (2.1 m by 762 mm)
  • Span is 3' 10" suggesting 8' (2.4 m) oars.  

  • Freeboard bow: 12" (305 mm)
  • ... midships: 6" (152 mm)
  • ... stern: 9" (229 mm)

  • Water Line Width: 3' (0.9 m)
  • WLL/WLW Ratio: 5.3:1
  • Hull Speed: 5.4 Knots, 10 kph, 6.21 mph

Summary-Pros:
  • A straight forward build based on Jim's Toto design.
  • Hull is built as Jim designed. The changes noted in The Safety Features in this Day Cruiser are all additions to his design.
  • Fast: A cruising speed of 4 mph (6.4 kph, 3.5 knots) for ten 45" sessions per day results in 30 miles (48 km) a day cruising. Jim states in his write-up for the plans "...she'll hit 6 mph in good conditions and cruise forever at 4 mph."
  • Carries a passenger comfortably without affecting trim.
  • Could be cruised in, but may require shelter. See this post on "Shelters" for alternatives.
  • Abundant dry storage.
  • Seaworthy based on waterproof end-compartments, full decking, coaming and under-deck flotation.

Summary-Cons:
  • Narrow hull at the water line results in a 'tippy' hull which is offset (somewhat) by the under deck flotation.
  • Heavy to car-top, although boats this long are easier to car-top than shorter boats of the same weight. See these posts on car-topping and this one by John Welsford.

    If most of your  rowing is 'day-cruising' and relatively little of over-night cruising, this design, with its ability to carry a passenger and it's speed, is an excellent option.





    2 comments:

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    2. Hi DJ, Thank you for your kind words! Much appreciated.
      Tom

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