Sunday, April 24, 2016

Model Boat Building

There are so many boats I’d love to build… but no place to store them.

So I build models instead. I’ll sometimes modify a design (but NOT the basic hull) or design my own. And if the modifications don’t work, rip them out and try again, enabling me to experiment with different arrangements… at virtually no cost. It's an effective way to learn the problems and issues that will arise if I were to build the full-size version. I get a good sense of what the real boat will look like, much better than photos and plans. And lastly, it satisfies (to some extent) that deep urge to build boats.

What tools do I use?


Tools Used in Model Making

  1. Sharpening stone to keep #14, #15 and #16 sharp
  2. Set of jeweler’s files, handy for fine ‘carving’ (e.g. cleats)
  3. Bunch of disposable nail files, really handy, used frequently
  4. A steel nail file, used to clean glue ‘squish outs’ on joints
  5. Tweezers for picking up really small parts
  6. Drill bit holder and small twist drill
  7. Dividers for creating arcs (e.g. for deck beams) and for stepping off measurements (more on that below)
  8. Protractor for measuring angles
  9. Set of weights ranging from 4 pounds down to 4 ounces, use to hold #24 (steel ruler on edge) for drawing curves, holding components to be glued, etc.
  10. Fine tooth saw for doing ‘cut-offs’ using the ‘bench stop’ (#26)
  11. Sandpaper, mostly used flat on the table and move the object to be sanded
  12. Fine lead (approximately .7mm) mechanical pencil
  13. Wood carving flat blade chisel, used very frequently
  14. Xacto brand knife 
  15. Xacto brand knife (more on these two frequently used knives below)
  16. Small plane, very handy because it can do things that nothing else does as well, such as trimming wood to a line, or tapering rub rails, etc.
  17. Small 30-60 triangle, often paired with the larger triangle for 90 degree lines
  18. Large 30-60 triangle
  19. Tape dispenser. Tape is used to hold parts together while glue dries. (example below)
  20. Wooden spring clothes pins (“One can never have enough clamps”)
  21. Hair clips also used as clamps
  22. Rubber bands also used as clamps
  23. Architect’s scale. The blue tape tab enables me to pick the ruler up each time oriented to the correct scale (usually 1 inch to the foot)  
  24. A steel rule, marked both Imperial and Metric. It is flexible enough to be bent to beautiful curves (held by the weights, #9). It has a thin cork backing that keeps if from sliding… also used as straight edge for slicing wood with the Xacto knives.
  25. Glue… I now use only TiteBond III III.
  26. A 6” long ‘bench rest’ glued to the base
  27. Base is a piece of chip board that protects the underlying drafting table. Note, after this photo was taken, I purchased an "OLFA Cutting Mat", 12" x 18" to replace the chip board. I strongly recommend this.  See www.olfa.com (I have no affiliation with OLFA.)

Not shown:


  • Paints: Acrylic paints produce a 'flat' finish, but typically require 3 or 4 coats to fully cover.
  • Rustoleum sells half-pint samples of their enamels. They provide a beautiful one-coat finish if you can deal with the smell (my wife can't so I use the acrylics).
  • Brushes: A set of inexpensive artist brushes
  • Small pair of cutting pliers used to cut brass wire
  • Small pair of beading pliers used to bend the brass wire… the jaws are cylindrical and tapered rather than flat
  • Wax paper to prevent gluing components to the base
  • Paper towels to whip off excess glue from fingers, tools, etc.

Materials:


  • 1/32 thick 4” x 24” sheets of bass wood, used for hull components (www.midwestproducts.com)
  • 1/8 thick 4” x 24” bass wood, used for making bulkheads, etc.
  • Assorted strip wood, although I’ll frequently just cut strips from the sheet wood and laminate them to the required thickness.
  • Brass wire… about 1mm thick… used to make oar locks, pintles, gudgeons, etc.


Techniques:


These are a few techniques I’ve learned that make model-making more accurate.

Convert Metric to Imperial:

Divide millimeters by 25.4 resulting in inches and tenths of an inch.


Converted Metric to Imperial Measurements

Dividers


These can be used to create arcs, such as deck beams, but also to replicate measurements (verses using a ruler) such as section spacing as in the photo above in which I needed to transfer 300mm intervals (11.8 scale inches) to the sheet bass wood as in the photo below.

Using Dividers to Step Off Accurate Measurements

Cutting 1/32” sheet bass wood:


Use the short blade (#14) Xacto knife by pushing the knife along the line, with the tip of the blade slightly raised (see photo below). Do NOT try to cut through the wood in one pass. If you do, it will likely split. Cut in a direction such that if the wood splits, it will split away from the object you are creating. This means that you may need to cut some of the line (assuming it’s a curved line such as the sheer or chine) in one direction and the rest of the line in the opposite direction.

When cutting the 1/8” bass wood, use the short blade knife (#14) to make the first 3 or 4 passes, then switch to the long blade knife (#15), held vertically, to make the final cuts with just the tip of the blade. Note, it will take about 6 or 8 cuts to get through the 1/8” bass wood. Sharp knives are critical.

Cutting Sheet Bass Wood by Pushing the Knife

Holding components together waiting for glue to hold:


Tape, clothes pins, hair clips and rubber bands can all be used to temporarily hold components together for gluing. In the photo below, the deck was cut about 1/8” over-sized, then tape was added to the deck as shown. (Note: Recently rely on 3/4 inch blue masking tape rather than 'scotch' tape.) A bead of glue was put on top edge of the bulkhead and the topsides. The deck was taped down, and the excess glue was immediately removed with the steel nail file (#4). The result was a tight seal between the deck and the hull after trimming with the plane (#16).

Preparing a Deck to be Glued to the Hull

Building boat models helps me to 'cheaply' experiment with different designs, teaches me techniques that can be used in building real boats, enables me to build designs that really appeal to me, such as Bolger's Japanese Beach Cruiser, enables me to (partially) fulfill my boat building obsession regardless of the weather. And it's fun!



Sunday, April 17, 2016

An Easy-to-Build Oar Cruiser


An Oar Cruiser based on a simple to build canoe.

Quick Canoe (built and photo by Rick Landreville)

Overview of lines (Source)

Quick Canoe model as an Oar Cruiser showing flotation



Quick Canoe model as an Oar Cruiser


Specifications of Quick Canoe as Designed by Michael Storer:

  • Length: 15' 6" (4.7 m)
  • Beam: 33" (838 mm)
  • Weight: 45 pounds (23 kg)
  • Water Line Length: 15' 6" (4.7 m)
  • Water Line Width: 29" (737 mm)
  • WLL/WLW Ratio: 6.4:1
  • Hull Speed: 5.3 knots, 9.8 kph, 6.1 mph

Conversion to an Oar Cruiser:

  • Lengthened the hull by about 6.5% to make the overall hull 16' 8".
  • Note: The only design change from Storer's plans (below the water line) is the increased length. That change in water line length has very little impact on her Hull Speed (2% faster) and therefore, If I were to build the boat, I would NOT increase the length as I did in this model.
  • Reduced the length of the two stems from 18.7" (474 mm) to 7" (178 mm). Increased the width of the side panels at midships by 2" (51 mm). Drew a new sheer line through these 3 points resulting in a reverse sheer line.
  • Added bulkheads with large access hatches approximately 4.5' (1219 mm) inside the two stems. This created an internal cockpit approximately 7' (2134 mm) long.
  • Added full-length cross-slatted floor boards to provide a sleeping platform and anchors for movable foot braces and rowing seat.
  • Added full decking with a cockpit opening 5' (1524 mm) long by 24" (610) wide. The deck is 4' (1219 mm) wide midships (extending 7.5" [191mm] beyond the topsides), tapering at the bow and stern.
  • Added a coaming around the cockpit opening 5" (127 mm) high at the forward end sloping back to 3" (76 mm) high at the aft end.
  • Added oar lock pads to the extended deck to provide an 8' span.
  • Added a fairlead and 6" (152 mm) cleat to the deck for anchoring (See "Anchoring" in this blog).
  • Added reverse reading compass just aft of the coaming.
  • Added 7 pool noodles (12" by 3.5", 305 mm by 89 mm) to each side of the hull under the side decking. This provides 29 pounds (13.2 kg) of floatation on each side of the hull, making re-boarding after a capsize easier.

Specifications of Quick Canoe as an Oar Cruiser:

  • Length: 16' 8" (5.1 m) (See note above)
  • Beam at the midships deck extension: 47" (1194 mm)
  • Beam at top of hull: 33" (838 mm)
  • Estimated Weight: 75 pounds (34 kg) due to decking and bulkheads
  • Water Line Length: 16' 3" (5 m)
  • Water Line Width: 29" (737 mm)
  • WLL/WLW Ratio: 6.7:1
  • Hull Speed: 5.4 knots, 10.0 kph, 6.2 mph

Summary-Pros:

  • Easy to build.
  • She would be fast due to her high WLL/WLW Ratio of 6.7:1.
  • The full deck, high coaming and flotation on each side would all help to make her more capable in heavy weather.
  • The reverse sheer reduces windage (at the ends) and adds a little freeboard at the cockpit.
  • The two water-proof compartments provide room for dry storage of supplies and equipment as well as emergency flotation.

Summary-Cons:

  • The narrow hull makes her more tender.

Re-boarding an Oar Cruiser:

He wasn't stupid; he just didn't think. It was late fall. No other boats in sight. Rather than get his 'pee-bottle' out, he just stood up and relieved himself over the side; lost his balance and fell overboard. He was in his Quick Canoe Oar Cruiser. (The flotation under the side decks would not support all his weight, but they would help.)

First, he pulled the oarlock out of the socket (both oarlocks and oars were tied to the coaming with light line). Holding the gunnel at the back end of the cockpit, he lay in the water on his side, parallel to the gunnel with his feet toward the other end of the cockpit. He then hooked his top leg over the gunnel and quickly rolled into the cockpit, ending up on his back in the middle of the boat. During the roll-in, more water came over the gunnel. He took his bailing scoop and without sitting up, scooped out as much water as he could. He wanted to keep his weight as low as possible because most water-filled boats are very unstable. After he got most of the water out, he used his big sponge (also tied to the boat) to get the last of the water out and vowed, "Never again…"

(Thanks to John Welsford for this technique of re-boarding)






Sunday, April 10, 2016

Rowing Geometry

This post is about rowing geometry for fixed seat rowing.

Colin Angus has a very complete description, with detailed measurements, of rowing geometry for sliding seat rowing.

John Welsford, in an article for Duckworks Magazine titled "Some Thoughts on Rowing" includes the following information for rowing geometry for fixed seat rowing (as well as much more excellent advice):
  • Distance between oar locks: Minimum of 3’ 10” (117cm), and an average of 4’ (122cm) to 4’ 4” (132cm)
  • Oar lock to back edge of seat: Minimum of 13” (33cm)
  • Bottom of oar lock height above seat: 8” (20cm) to as high as 11” (28cm)
  • Seat height above ‘heel rest’ on foot brace: 6” to 8” (15cm to 20cm)

Paul Truszkowski’s rowing geometry for his Michalak Vireo is:
  • Distance between oar locks: 49.5:, 126cm
  • Oar lock to back edge of seat: 13”, 33cm
  • Bottom of oar lock height above seat: 12.5”, 32cm
  • Seat height above ‘heel rest’ on foot brace: 8”, 20cm
  • Bottom of oar lock to waterline: 13.5”, 34cm
  • Length of oars: 96”, 244cm
  • Overlap when oars are level: 4”, 10cm
  • Paul's height with shoes he normally wears when rowing. 6’ 1”, 185cm

Rowing Geometry for my own Ross Lillistone Flint is:
  • Distance between oar locks: 53”, 134cm
  • Oar lock to back edge of seat: 10”, 25cm. The oar locks are closer to the seat because I like to make a deeper recovery (forward angle of oars at the catch: 50 degrees) and shorten the end of the power stroke (35-40 degrees aft)
  • Bottom of oar lock height above seat: 10”, 25cm
  • Seat height above ‘heel rest’ on foot brace: 10”, 25cm
  • Bottom of oar lock to waterline: 14.5”, 37cm
  • Length of oars: 96”, 244cm
  • Overlap when oars are level: 3”, 76mm
  • My height with shoes I normally wear when rowing: 6’ 1”, 185cm

An effective ‘rule of thumb’ for adjusting the foot brace is to sit on the seat in your normal rowing position, extend your legs until your thighs are level, then position the foot brace against the bottom of your feet.


Pictured below is a Rowing Geometry Worksheet you can download from Dropbox and then ‘model’ your own rowing geometry based on you, the size of your boat and the length of the oars.

A Rowing Geometry Worksheet you can Download and Use

Sunday, April 3, 2016

Seven Ways to Make Foot Braces

"Foot braces", aka “Foot stretchers” or “Foot risers”, are used by both sliding seat and fixed seat rowers. They are the braces that keep you from sliding aft when you row. 

In terms of design, there are probably as many designs as there are rowers. Following are seven examples, in no particular order. 

 
Steve Chambers' SOF British Columbia Hubert Evans Handliner
 
Detail of the Foot Brace and Box Seat

1. Steve Chambers built a SOF British Columbia Hubert Evans 14’ 6” Handliner (4.4m), using a plywood floorboard with a center stiffener strip. Both the box seat and foot brace are grooved to sit over the stiffener strip. Steve says the rope loop (around the back of the box seat and threaded through the foot brace) works well as long as you put equal pressure on the two ends of the foot brace. Distance between the foot brace and the box seat is adjusted by the sliding knot (tautline hitch or rolling hitch?... latter is less likely to slip).

==========



Close up of the Foot Rest and Straps

Rick Thompson's Foot Braces

2. Rick Thomson made these foot braces for his Walkabout (Rick's Walkabout). As with all of Rick’s work, these are elegant and superbly made. Note that Rick uses these for both sliding seat (for racing) and fixed seat rowing. 

==========

3. John Welsford's design for the Walkabout specified a series of about 6 paired ribs (about 12mm square) attached to the side of the air boxes at the same location as Rick placed the notched supports for his foot braces. John’s ribs are angled back from the vertical about 30 degrees and are spaced about 12 to 14mm apart. The actual foot brace is a plank that slides into the slot between ribs. 


==========


Paul Truszkowski's Drop-in Rowing Unit, Integrating Seat, Foot Rest and Outriggers

The Rowing Unit in a Custom 15' 6" Kayak/Rowboat

4. Paul Truszkowski built a drop-in unit that combines foot brace, outriggers and a seat.   

========== 

Adjustable Foot Brace Attached to Seat in a Michalak Vireo

5. In Paul’s Vireo, the foot brace is attached to the seat by adjustable chains. I’ve used this and it works well. 

==========


6. In the model Vireo, another adjustable foot brace is shown. It is hooked into the slats of the floor boards, as is the box seat, to allow both to be adjusted for leg length and fore/aft weight distribution. 

==========


Adjustable Foot Brace for a Ross Lillistone Flint

Forward End of the Brace Held in Place by a Wedge

Underside of the Foot Brace

After End of the Brace Showing One of the Wing Nuts

7. For Ross Lillistone’s Flint, I made this adjustable foot brace. The forward end is held down by a wedge jammed under the block screwed to the bulkhead. Two wing nuts anchor the sliding foot brace on the slotted beam, providing a wide range of adjustment. (Note that the only fasteners used are the two wing nuts. All the other joints are held only by Titebond 3 which has held up for two seasons.)


What would I do differently in making this foot brace? 


a. Make the actual brace much taller. I find it more comfortable to have the ball of my foot supported by the brace in addition to the heel. In addition, I’d make the brace wider so that I could brace my feet better (wider) in rough conditions.  
b. Create a better way to secure the front end of the slotted beam. The wedge is just okay, but has a tendency to work loose. 
In the March 2016 issue of Small Boat Monthly, Ben Fuller wrote an article on foot braces, in which he shows 10 different designs of foot braces. With a total of 17 different designs, there should be a style that is suitable for your oar cruiser.