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

Introduction:
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 and a small cabin large enough to sleep in. This page documents the design and build process which began mid-winter 2018-2019. The menu at left is also my 'To Do' list.

boatshop on April 8, 2019

This is obviously a work in progress; you can see the latest update here.

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: http://www.carlsondesign.com/hulls.zip 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.


Foot-brace:
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 650. 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 have purchased a Ritchie Reverse-card rowing compass and am looking forward to having a compass that reads the direction the boat is traveling even though you are facing the stern.

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 plan on doing the August trip has very limited coverage but I'll want to keep a phone charged anyway.

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%  

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. The versatile and powerful Greenworks batteries power our mower, trimmer and a electric chainsaw as well as our Bose PA system. I have installed the battery base, battery and a 15-Amp Drok DC to DC converter in a waterproof utility box and a couple of cables carry the power to a remote power panel that will be mounted in the cockpit. The box will be secured in the port cockpit flotation/storage compartment.
power unitpower panel

  • The Meter on the left indicates the battery voltage and % full; as you can see, the battery is currently full at 41.6 Volts.

  • Master Switch: Cuts power from the battery to the converter. No power flows out of the box except for the battery meter.

  • USB Charging Ports - 2 x 2.1 Amp 5-volt charging ports. 4.2 Amps total capacity. There is a waterproof cover on the port.

  • Panel Voltmeter: Indicates output from the DC/DC converter, available for charging and lights.

  • Light Switch: Turns on/off the wired but removable running/anchoring light.


Nav/Anchoring Light

Navigation/Anchoring Light:

I've put together a lightweight removable light for use when rowing after sundown and night anchoring. My Dad had a really nice Wonder-rod fly fishing rod that was crying out to be reused for something useful. I don't fish and had tried to sell the rod at a garage sale with no success. I used the lower, handle section and a few inches of the middle part as a strong, light shaft for the light.

The light is made up of six super-bright 5050 SMD 12-volt LED segments  arranged in a cylinder. Each LED has a 120 degree beam angle and with this layout you can always see two LEDs. I use a single one of these LEDs as a power-on indicator for our 'panel-cam' and it is easy to see it even in daylight 125 yards away.

The fishing rod is totally hollow so wiring it was easy. I installed a female RCA connector in the bottom end of the handle and it will mate to a wired male connector in a 5'8" ID aluminum mounting base. There will be two bases; one at the stern for use while anchored and another just forward of the cockpit for use while rowing. There is a black disk just below the LED level to minimize the amount of light that will shine down into the boat.



Construction:
It is nearly spring here in Michigan's Upper Peninsula with daytime temperatures near 40° F. That makes it possible to heat up the shop and finally get to work on building this boat. 4/2/2019

- Frames:68 Clamps ...
3/29/2019 - The frames are made from two layers of 1/4" Baltic birch plywood; the only good, flat, waterproof plywood available locally. It is heavier than real marine plywood but it has 5 plys and waterproof glue. There are zero voids and as a test I have boiled a scrap of this plywood for days with no delamination.

I transferred the frame layout to the plywood and cut around each piece with a saber-saw then cleaned up the outlines with a fine-tooth blade in my old 1930's 12" Craftsman band saw. Today I epoxied half of the pairs together - ran out of clamps (68), and will laminate the rest of them tomorrow. Doing the epoxy work in the (warmer) house shop.
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- Strongback:Strongback setup
4/2/2019 - Today I finished the last of the frame laminating so it was time to put together the strongback on which the boat will be built. I'm reusing the beam I've used for all three of our SOF boats but because this boat has practically no overhang at the bow and stern I needed to make the strongback much longer. I added four feet to each end of the original 10' beam. It is screwed to two sawhorses and two end supports which are in turn screwed to the floor. The top of the beam is flat and level and immovable. I'll measure and mark the frame locations next. I had a fire in the shop's woodstove and it got up to 55° in there today - very comfortable for the kind of work I was doing.

- Stringers/Gunwales:
Long parts sawn ...
4/3/2019 - For months it seems, I have been trying to decide how heavily to build this boat. One of the main considerations is what dimensions should the keel, stringers and gunwales be. Too large and the boat gets heavier than it needs to be; too small and the integrity and shape of the boat can suffer. Today I finalized the dimensions for those long pieces and ripped them from some 10' long, clear New Zealand pine using a thin-kerf blade in a circular saw with its fence.

The sizes:
Keel  1-1/8" x 3/4"
Lower stringers  3/4" x 3/4"
Upper stringers  7/8" x 3/4"
Gunwales  1-3/4" x 3/4"

When these are paired up and scarfed end to end they will be about 19'-6" long and quite unmanageable. A good job for tomorrow.



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- Setting up the frames:Gunwales temporarily on frames
4/9/2019 - It's starting to look a little like a boat. I have the frames clamped in position on the strongback and have temporarily clamped the gunwales in place. This helps with decisions about whether to refine the boat's shape at this point and I could see how much trimming I needed to do of the stringer locations to make sure the boat remains straight.

I like the overall shape and will check a few of the dimensions to be sure that for instance, I can fit in the cockpit comfortably. At that point the boat is about 36" wide but the cockpit is only 20" wide. In theory the smaller the cockpit area the safer the boat will be since in the event of a capsize the cockpit is the only area that would take on water (assuming that the hatches are closed securely).

With the rest of the boat acting as flotation any water that  gets into the cockpit would empty completely when the boat is righted - no bailing, just crawl back in over the side and get back to rowing.

 - More frame work:Frame bottom as seen from the bow
4/14/2019 - The gunwales and stringers are installed with screws (no glue) at this point so that I could remove the frame from the strongback and confirm that the hull has sufficient rocker. A little scary since I suppose it is possible that the whole thing could kind of slide out of shape but it all held together remarkably well and Sue and I could easily flip it over. There is about 1-1/2" of rocker at each end and that looks about right for this hull shape.

The flat bottom looks unusual but according to Colin Angus a long narrow hull, sharp angles at the chines, and moderate rocker will combine to eliminate the need for a drag-inducing outer keel or skeg. To ensure that I don't lose the rocker I'll remove each screw and glue the joints with the boat in this position, supported in the middle with the ends kind of hanging there. I have checked the hull for straightness since it is off the strongback and all is well.





4/27/2019 - Boat building is sharing time with spring homestead chores like brush cutting (before the birds build nests) and firewood cutting. Yesterday we were able to drive in to our house and shop for the first time since December which makes supply transport more convenient.
Aft deck stringers in place
The photo is of the stern of the boat, looking forward.

The frame is upright and I have installed the aft deck stringers and am in the process of designing an building the hatch opening in that deck. I have mounted one of the rigger base plates (where the oar lock extensions will mount) in the frame and will install the other today.

I have been in and out of the boat a few times adjusting the sliding seat position. It looks like I'll fit OK in the cockpit but it will be a different experience rowing in that narrow (20" wide) space. Kind of cozy feeling. The fore and aft location is established but I'll wait until I can fit the riggers and oar locks before deciding on seat height.



 

- 'On-the-fly' engineering - as usual:
5/9/2019 - I climbed into the 'cabin' the other day just to be sure it would be comfortable and it felt quite a bit too low. Plenty long enough and good elbow room but the original plan didn't allow enough height in the shoulder area to easily roll over. By laying a yardstick across the gunwales and a bit of fiddling around I determined that another 3" height would be nice. So, at the risk of increasing windage, the boat's susceptibility to cross-winds, I designed a solution that involved adding 8' long, skinny  triangular pieces to the tops of the gunwale in the cabin area.
Laminatin gunwale extensions
The additions are made up of two layers of 5/16" thick pine paneling boards laminated using some small frame extensions above the gunwales. Hard to explain but here is a photo of yet another clamping extravaganza. I ended up adding about 3-1/2" height at the center frame tapering down to nothing a foot or so from the bow.

On a related subject I'm working on a different hatch design for the cabin. The original plan had a fairly large lift-off hatch for loading stuff into the 'hold' but it was lacking in ease of getting from the cockpit into the cabin while afloat. More on that as the scheme develops...

- Skin:

- Waterproofing:

- Final Fit-out:


Notes:


Contact:
Steve Schmeck
steve@manytracks.com
www.ManyTracks.com

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