Skin-on-Frame Adventure Rowboat Project
Adventure Rowboat
By Steve Schmeck - 2019

For many years I have set myself the challenge of riding my age, in miles, on one of my recumbent bikes; last year 74 miles. It has been fun and getting myself into shape for the annual ride has been good for my health. Although I have been very fortunate and never had an accident or even a close call while riding I feel it is time to switch to an adventure with less traffic.

I have sold my main bike and plan to use part of the proceeds to build a rowing boat designed specifically for my new challenge: Row my age, in miles, in 48 hours.

The boat will be a lightweight Skin-on-Frame design with one rowing position, a sliding seat, a small cabin large enough to sleep in. Seems simple enough:

[√] Design the boat
[√] Purchase needed materials
[  ] Prepare the materials
[  ] Build the frame
[  ] Cover the boat
[  ] Apply waterproofing/finish
[  ] Install rowing systems
[  ] Install ancillary systems
[  ] Test the boat and all systems
[  ] August, 2019: Row 75 miles in 48 hours

I will update this page as I progress through the project. Your questions and comments are welcome.    Contact

Basic Design:
The trip will probably be along the northern coast of Lake Michigan beginning at a launch site less than 10 miles from home. For this kind of rowing adventure I want a relatively fast, easy rowing boat. A few other features I'd like to include, in order of importance; seaworthy, safe, stable, light weight, room to sleep on board, maybe room to haul a folding bike & trailer. Oh, and easy to build and not too expensive would be nice, too. It will be 18 feet long as that is the longest length that fits nicely in my boat shop.

After a lot of research I found a boat that I'm using for inspiration for this new boat; Colin Angus' Expedition Rowboat. I seriously considered ordering the plans for the boat from him but since I'm not going to build it out of plywood (I'll be using Skin-on-Frame technique like on our three other boats) and after discussing several major modifications with Colin, that didn't seem like the way to go. If I was going to use the stitch & glue plywood construction technique I'd definitely purchase his plans ($139 for PDF plans & manual) since they include full size printable patterns for the hull panels.

'Hulls Designer Software':
My main tool for creating scale drawings for our previous boats was Adobe Photoshop but for this project I switched to Carlson Design's "Hull Designer". This is an incredible, free program for Windows that seems to run best in Windows XP compatibility mode on my Windows 10 laptop.  The included manual is only 4 pages long and there is a bit of a learning curve, but after a some experimentation it did a great job. After several refinements I now have a good set of offsets for all seven frames. In the process it also helped me create a cutting layout and told me that with a displacement of 250 lbs. (boat + my stuff and me) it will draw 2.56" of water. Pretty cool.

    Frame Cutting Layout    Offsets Table    'Hulls' wireframe

The Hull Designer program also can create VRML files which, with a free plug-in can be loaded into a browser and spun around in 3d as a solid object. I found this option interesting but it didn't seem to show all of my chines so wasn't as useful as I'd hoped for double-checking hull fairness.

You can download the Hulls program, manual and a whole bunch of example files as a .zip file here: Caution: click that link and the download will begin immediately!

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Frames & Bulkheads:
I decided to space the frames and bulkheads 27" apart on the advise of Dave Gentry. As it turns out, if you divide 18' into eight equal parts it comes out to exactly 27" - very handy. I also lucked out in that frame #6, a solid  bulkhead, is in perfect spot for the aft end of the cockpit. I will mount the foot brace unit right to the bulkhead. Here is the frame layout drawing (Photoshop again):

Frame layout @ 27" spacing

Frame #4, in the middle of the boat is also a solid bulkhead. If the hatches are secured the only water that would enter the boat in a capsize would be in the cockpit. The rest of the hull volume is flotation. All other frames are open; here is the latest, though probably not the final, frame nesting drawing:

Nested Frames     <^ click to see enlarged images

Sliding Seat:
The sliding seat unit is made up of a suspended mesh seat; a smaller version of the one that served me well on my Lightning P-38 recumbent bike. The tracks are made from some on-hand 1-1/4” aluminum angle and the custom under-carriage was made from that aluminum angle plus some repurposed (Goodwill) roller blade bearings and a bunch of bolts & locking nuts. The undercarriage was based upon a similar, simpler design from a great article by Ben Fuller and Chris Cunningham in Small Boats Monthly on-line magazine. Thanks, Ben & Chris! The tracks are 22” long and the effective slide is 14-1/2”. This is quite a bit shorter than commercial sliding seats but feels right since I'll probably be using my 8'-4" oars rather than 9-1/2' sculls.

I ran an elevated aluminum bar down the middle that gives my little ‘keeper’ device something to follow and hold the seat on the tracks in the event of a capsize or other unplanned event. That 'keeper' also limits glide length when it hits the rubber stop pins at each end of the bar. The seat can easily be removed from the base by flipping a couple of HDPE latches (inset below, right). The whole sliding seat unit can be removed by rotating a couple of aluminum latches that will hold it to a solid rowing thwart. In other words, if there is some kind of problem with the sliding seat I can just remove it and keep on rowing sitting on the fixed thwart below it.

Sliding seat     Seat bearings & 'Keeper'

The tracks are lined with 1” x 1/8” high density polyethylene strips to keep the sliding action smooth and quiet. As you can see in the inset above left, the seat is also free to rotate. The rotation feature eliminated any tendency of the rolling carriage wheels to bind on the tracks when turning to see what's ahead and makes that movement comfortable. I have the whole setup mounted on a temporary sub-base and have 'rowed' many miles here in the house. So far it seems smooth, quiet, though not silent, the ‘keeper’ system works well and there doesn't seem to be any noticeable wear on the PE runners.

I have designed and built a hybrid foot-board/stretcher for this boat. Over the years I have become comfortable using clipless pedals on my bikes and it seems as though the things I like them best for on the bike would also carry over to this boat. The Shimano SPD pedals I'm using hold your feet securely but allow plenty of rotation laterally. They release instantly with a quick twist of your foot. The only drawbacks I can see are that you do need to wear shoes that can accept SPD cleats and those shoes might not be your first choice for boating footwear.
Clipless foot stetcher
I created my stretcher unit by modifying/butchering a couple of salvaged bike cranks (free from local bike shop) as shown in the photo. Those 7/8" square threaded blocks were epoxied into the ends of a 6-inch piece of 1" x 1/16" square aluminum tube. There is a wood filler block to keep the tube from crushing and to help position the threaded parts. I used what I consider to be the best epoxy for this type of assembly, West System G/flex 850. This is a toughened epoxy that is not brittle when cured and adheres well to just about any material.

In the construction photo you can see some old egg-beater style pedals I used for setup but I am using some well broken in Shimano PD-M535's:

SDP Stretcher< Click either photo for larger view >

This 'stretcher' is currently mounted low on a wall in the house and we have been using it regularly with the sliding seat unit.

Navigation Equipment:Navigation tools ...
I plan on using a couple of navigation tools on this boat; primarily a chart and compass and as backup and entertainment, two apps on an Android tablet. I'll probably get a Ritchie Reverse-card rowing compass for ease of use but to begin with I'll be using the one pictured.

My main electronic navigation device is an older Samsung Note 10.1 tablet. I have decided to use two apps; Marine Navigator, for route planning and navigation and LD-Log for course tracking. Both apps are fully integrated with the tablet's GPS capability. My thought is that during a full day or two of rowing I may welcome a bit of useful diversion.

Electrical System:
You wouldn't think that a rowboat would need an electrical system but since I expect that my August trip will include some after dark rowing I will be installing a 360 degree navigation light. And while I'm at it I'll make sure there is enough power to keep a tablet with navigation and tracking apps charged. Training rows will most likely take place on nearby Indian Lake which has OK cell coverage but the area of the north shore of Lake Michigan where I expect to do the August trip has very limited coverage but I'll want to keep a phone charged anyway.

The power source is a 40 volt, 4 Amp-Hour lithium Ion battery running through a DC to DC converter down to 12 volts for lights then reduced further to 5 volts for device charging.

Electrical Loads analysis:

Load Description Amps Volts Watts Amps @ 40V Hours of Use AmpHours Used
Navigation Light 0.11 12 1.3 0.03 12 0.36
Android Tablet 0.5 5 2.5 0.06 12 0.72
Cell Phone 0.25 5 1.25 0.03 12 0.36
          Total AHrs Used > 1.44
          Battery Reserve: 64%  


(Coming as soon as the shop temperatures warm up a bit. 12 below zero tonight,  Feb 25th.)

- Strong-back:

- Frames:

- Stringers/Gunwales:

- Skin:

- Waterproofing:

- Final Fit-out:


Steve Schmeck

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