"Marksbark": An 18' Oar Cruiser

“Marksbark” is a Jim Michalak design for a row boat (can also be paddled) that is, in effect, a stretched out Toto (one of Jim’s most popular designs).

Plans for "Marksbark"

Specifications:

• Length: 18' 0" (5.4 m)
• Beam: 36" (914 mm)
• Weight: 90 pounds (40.1 kg) as designed
• Water Line Length: 16' 7" (5.1 m)
• Water Line Width: 29" (737 mm)
• WLL/WLW Ratio: 6.9:1
• Hull Speed: 5.5 knots, 10.2 kph, 6.3 mph

Conversion to an Oar Cruiser:

By adding full decking, a coaming, out riggers for the oar locks and semi-permanent bows (to support a removable tent), she could be converted into a very fast, sea-worthy oar cruiser.

Marksbark Converted to an Oar Cruiser

The bottom, chine and topside panels were cut as designed, which ensures the hull shape is exactly as Jim designed. Once the hull was constructed, the following additions/changes were made to create the oar cruiser:

• Two full bulkheads, with tops crowned 2" (51 mm), were installed 6’ (1.8 m) and 13’ (4 m) from the bow. 
• The frames outboard of these two full bulkheads were permanently installed with the tops crowned to the same radius as the new bulkheads.
• The two new bulkheads are just slightly less than 7’ (2.1 m) apart, allowing a 7’ long sleeping area once the temporary form (10’ [3 m] from the bow) was removed.
• The foredeck is 7’ (2.1 m) long from bow to forward edge of the cockpit.
• The afterdeck is 6’ (1.8 m) long from the after edge of the cockpit to the transom.
• Side decks were installed leaving a 2’ (0.6 m) wide cockpit, 4’ (1.2 m) long.  
• A 3” (76 mm) high coaming was installed on all four sides of the cockpit.
• A ¾” (19 mm) by ¾” strip was installed on the outer top edge of the coaming  to stiffen it. And another ¾” by ¾’ strip was installed on the inner top edge of approximately 2.5’ (0.8m) of the sides of the cockpit coaming. This combination of strips support the outriggers and enables them to be removed, rotated 180 degrees (to act as ‘tables’ while anchored) and adjustable to accommodate the rower.  
• The span of the oarlocks using the outriggers is 4’ (1.2 m) , accommodating 8’ to 8’6”  (2.4 to 2.6 m) oars.
• The forward hatch is 16” (406 mm) wide by 14” (356 mm) long, providing access to the forward compartment;
• And the after hatch is 14” by 14”.
• The support bows are bolted (using wingnuts so they are easily removed for car-topping) to the coaming. The bows provide 4’ (1.2 m) ‘headroom’ from the top of the floorboards, sufficient for sitting on a cushion.
• The floor boards are in two sections (spanning the space between the two new bulkheads (6’ [1.8 m] and 13’ [4 m]) and consist of cross pieces ½” (13 mm) apart. This enables the rowing seat and footrest to be ‘hooked’ into the floor boards to provide a solid and adjustable rowing station.

Interior of Marksbark Oar Cruiser Conversion

If I were to build it full size, I would consider using SOF for the decks in order to lighten the overall weight. Jim calculates the boat will weigh 90 (41 kg) pounds as he designed it, using ¼” plywood. Adding the plywood decks would add approximately 30 (13.1 kg) pounds. 

Marksbark (bottom) Compared to Larsboat Concept Model

Summary-Pros:

• High WLL:WLW ratio (6.9:1) make this Oar Cruiser fast. Jim states in his write-up for the plans "…she'll hit 6 mph (5.2 knots, 9.7 kph) in good conditions and cruise forever at 4 mph (3.5 knots, 6.4 kph)."
• A cruising speed of 4 mph (6.4 kph) for ten 45" sessions per day results in 30 miles (48 km) a day cruising.
• Lowering the stem/transom tops, and increasing freeboard midships, resulting in a reverse sheer, reduces windage, but keeps the underwater lines as designed.
• Adding decks, coaming, splash guard all add up to making her very seaworthy.
• The two water-proof compartments provide storage as well as emergency flotation.
• Jim feels Marksbark could be rowed at 6 mph (9.7 kph) in good conditions and "cruise forever" at 4 mph (6.4 kph).

Summary-Cons:

• The addition of decking and bulkheads adds approximately 40 pounds (18 kg) to her weight. Long narrow boats as heavy as this can be car-topped by one person.

Floorboard Alternatives

I like floorboards in a boat: they provide a flat place to stand or sit, or even sleep. They keep you out of the inevitable bilge water that collects and they can look really nice.

Following are some examples of floorboards that may give you ideas for floorboards in your oar cruiser.

Teak Grid Floorboards

This is from Cruising Concepts. Make your own grid floorboards with a table saw with dado blade… and a cutting gauge and careful measuring.

Sectional Floorboards

These a floorboards from Nexus Marine are in sections between each frame. One advantage for an oar cruiser with floorboards such as these, with athwartship planks, is that the slots between planks provide stops (anchor points) for an adjustable foot brace and rowing seat.

Floor Boards and Foot Brace by Ben Fuller

These floorboards were featured in the March 2016 issue of Small Boats Monthly. The foot brace is anchored by a pair of wing nuts and bolts, enabling adjustment for different rowers.

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Fore-and-Aft Plank Floor Boards in a Canoe

Another set of floorboards using fore-and-aft planks is from Grapevine Point Boat Works, seen in a beautiful wood lapstrake canoe (Iain Oughtred's 'Wee Rob' design).

Floorboards for a Michalak Tween

This is a floorboard I made for a custom Michalak Tween. The ‘slats’ are ¾” by ¾” (19mm by 19mm) ripped from flooring planks. Two strips of 6mm plywood, running from one side to the other under the center section, hold (in addition to Titebond III glue) all the slats together. Finish is multiple coats of ‘exterior’ Watco oil.

I hope these samples have provided ideas for floorboards in your oar cruiser or small boat.

Making Shelters for Small Boats

Last week we posted a set of photos and diagrams of shelters/tents that can be used in oar cruisers. 

Following is an addition that is a perfect follow-up to that post: Paul Butler’s very informative article on how to make and set up shelters for small boats.

Just One Example of the Illustrations in Paul's Excellent Article

If you are thinking of creating a shelter/tent for your open boat, read (study) this article!

Thanks to Justin Miller for the link.

Two More SOF Oar Cruiser Candidates

In the May 15, 2016 post in the Oar Cruising blog, we presented two Dave Gentry Skin On Frame designs that could be converted into ‘oar cruisers’. We present two more designs here…

Further correspondence with Dave Gentry of Gentry Custom Boats Gentry Custom Boats...

(Dave) “The Shenandoah Whitehall is actually my best all-around rowboat, by far. Good stability, good capacity, good freeboard and she's a lot better in waves than Ruth (one of them has actually been used to play in the surf along a beach)” 

Dave Gentry's Shenandoah Whitehall...

...and the framework for the Shenandoah Whitehall

(Tom) “I understand your concern about Ruth (too low for open waters). To convert it to a ‘row cruiser’, I would see doing what you’ve done with the Chuckanut 15… This would, I believe, make a very fast, yet safe boat for open waters, with much less windage. Given this change (adding deck as in Chuckanut), would you see any problem of Ruth being a row cruiser?” 

The Chuckanut 15

...and the framework for the Chuckanut 15

(Dave) “Ruth with fore and aft decks - I'd make them of fabric, as you say - would help. Side decks, like the C15, would add some safety and reserve buoyancy, at the expense of cockpit space. Might work fine, though I still think the sides are too low amidships." 

(Dave) "The C15 itself would make a nice rowboat.”

For flotation, I’d use a set of empty screw-top plastic bottles in a net bag at each end.

The advantages of these SOF oar cruisers are their:

• Light weight (easy to car-top)… 
• Less expensive to build than the same boat in, for example, Ocume… 
• Easy to change the length of the boat when building (but check with Dave first!)… 
• Beautiful lines.

More on Sanitation in Small Boats

On June 19, 2016, we posted "What's Done Daily But Seldom Discussed?, about sanitation on small boats. Helena Smalman-Smith, in her site, "Expedition Rowing" wrote "What people REALLY want to know about long-distance rowing (sadly)". In her delightful style, she describes how she and her husband handled the sanitation problems in their row across the Atlantic. Most of us will never row across the Atlantic, but she makes it sound like it could almost be fun.

Shelter (Tent) Options for Oar Cruisers

In the definition of an ‘oar cruiser’ (see definition under "About This blog"), the rower is going to sleep in the boat. How do we provide shelter from rain and bugs while sleeping, cooking, eating etc.?

Option 1: Hope it doesn’t rain and bring lots of insect repellant.



Option 2: Use a ‘bivy’ such as the Uber Bivy

The Uber Bivy with Rain Hood Folded Back

This provides rain and bug protection while sleeping and is easily and compactly stored. However, no protection while cooking, eating, etc.

Options 3 & 4: Tents

Following two alternatives are from PDRacer,com

The first is “The Bottomless Tent”

The "Bottomless Tent"

It is a 4’ x 6’ child’s tent with the bottom cut out.


The second is “The Puddle Duck Tube Tent”

The PDR "Tube Tent"

The ends are plywood with clear deck plates available from Duckworks.
I’d mount the deck plates on the inside of the ends and use small patches of window screening on the outside.
The aft end is fastened with shock cord to an available cleat and the forward end is tensioned with a line attached to a second cleat and running through a small hole in the panel to a jam cleat on the inner face.
If the plywood ends were foldable (hinged on vertical seam?), then the whole tent could be more easily stored.


An open-ended variation of the “Tube Tent” could be made from a rectangular section of, for example, Polytarp, with 3 or 4 sleeves that hold fiberglass tent poles.
Add 6 or 8 ‘sockets’ (see Duckworks for a wide variety of components that could be used to create this custom shelter) on the decks that would hold the ends of the tent poles. This would provide an open ended tent that would provide rain protection for sleeping, cooking and eating. However, being open ended, no protection from bugs, and if there was wind, not much protection from rain.


Option 5: Bimini Top

Rick Thompson's Custom Bimini Top

This is a Bimini top Rick Thompson made for his Walkabout.
A Bimini top could be designed to provide sun protection for the rower and, with multiple sets of deck fittings, could be lowered to cover a (small) cockpit to provide rain protection while sleeping, but no bug protection.


Option 6: Matt Layden’s Sand Flea demonstrates another alternative.

Matt Layden's Sand Flea

The sliding hatch covers the cockpit and provides sleeping protection from rain and bugs, but not while cooking/eating, etc.
In an oar cruiser, since the cockpit must be at least 4’ (1.2m) long, two hatches would probably be required, meeting in the middle with an overlap joint.
Ventilation is strongly recommended for any ‘shelter’ solution that is closed, such as this. My Boat Gear has a good description of various ventilation solutions, some of which are suitable (either purchased or made) for oar cruisers and other small boats.


Option 7: Rick Thompson designed and built a very elegant shelter solution for his Walkabout.

Rick Thompson's Custom Shelter for His Walkabout

The two end components fold down to the fore and aft decks. The middle section, used only when full protection is needed, attaches to the other two sections.

Option 8: Dedicated sleeping compartment.

For many, the best solution is a separate ‘sleeping’ compartment as in Colin Angus’s RowCruiser.

Colin Angus's RowCruiser with Sleeping Cabin

It is really nice to have a dedicated sleeping compartment such as this. However, there is no protection when cooking, eating, etc.

Option 9: Boom tent.

One of Malcolm Forbes many boats he has owned is a 16’ (4.9m) Crawford Swampscott Dory in which he currently cruises. These photos show how he has designed and built a shelter system that enables him to sleep comfortably and yet row with some protection.

Malcolm Forbes Swampscott with Shelter Fully Rigged

Here, the Shelter has been Rolled Back to Enable Rowing

The Four-piece Sleeping Platform

The shelter is held up by the 'sprit' which is supported by the halyard and a topping lift. The edges are attached to 'hammock hooks' screwed to the bottom of the rub-rail along the shear line.

Option 10: Hoops to support a 3-part tent.

Using Removable Hoops to Support 'Tent'

The 'tent' consists of three pieces: A top that snaps to the outside of the hoops and can be rolled up (as shown) when rowing. Two side curtains which snap to the inside of the hoops and are used only for rain protection at night.

Option 11: Two hatches that slide on rails.

See this post for more information.

Option 12: A custom tent.

This is the custom tent that is included in the plans for the Pacific Loon. 

Also see Paul  Butler's article for how to make a custom tent.