Arcebus 

    From 22 inch Model to 18 foot Boat -- Construction Log

Arcebus

Jewelbox

Balinese Fish Boat

Nutshell Pram

Arcebus Model

Construction

sails

mast and spars

lofting

flying boat shelter

building jig and frames

planking

spiling the planks

xynoling the bottom

timeout for a wedding

building cabin-end frames

power plant

ready for turning

turning it over

examination by long-suffering wife

grandkids ready to go sailing

current status

What is an Arcebus?  I came across the word in a novel about resistance to the Spanish conquest of Mexico.  It was the name of an early matchlock gun.  I picked the name because I liked the way it sounded and because when you look at this boat you see a little bit of an ark and a little bit of a bus. 

Whatever compelled me to do this?   Boat building/sailing has been my primary hobby for many years.  I have 4 homemade boats (not counting Arcebus).  So, why did I build another one?  I admit it -- I'm addicted.  I like the challenge and the satisfaction that comes from building and using your own boat.  For me, there is no other activity that is as rife with possibility.  For every moment you spend working on the boat, there are ten that you spend daydreaming about the ways you're going to use it, the methods you'll use building it, the places you're going to go with it, and the adventures that you will be able to share with others on it.  Aside from a couple of simple kayaks, it's been 13 years since my last boat-building project, 9 of which have been dominated with the intense financial pressure of putting my three kids through college.  For me, this was a self-indulgence that I've been dreaming about, but unable to do for many years. 

The boat is a hybrid of two designs that I admire.  The first is Jim Michalak's Jewelbox.  I borrowed his concepts of a 12 foot long, walk-through cabin, self-righting hull, transom bow from which you can step onto the shore, and a pivoting leeboard.   You can stay out of the sun and stay warm on cold or wet days.  For me, one of the biggest selling points is the containment it provides for children.  I have 2- and 4-year old grandchildren and I see this as a great boat for camp-cruising with them.   You can see these features in the picture and appreciate their practicality, but you can also see that the hull is far from a thing of beauty.  The flat bottom would also pound like crazy when motoring in a chop.

Michalak's Jewelbox  

I just couldn't see investing the amount of time it would take to build a boat that ended up looking like that, so I played around with several alternatives.  The first try was just a whimsical effort at disguise -- could I make it look a little bit like a Balinese fish boat (or at least a Minnesota musky)?  It would be fun to take the grandkids sailing in a big fish.  With the help of my sister and brother-in-law, who is an Indonesian artist, we came up with the following alternative.

  in disguise   real Bali boats

I finally decided the novelty might wear off and I'd still be stuck with a boat that pounded badly in the waves.

I kept thinking about ways to "improve" the hull form and finally focused on a hull that I was very familiar with and enjoyed looking at -- the Nutshell Pram.  The Nutshell Pram was designed by Joel White and has been heavily promoted by Wooden Boat Magazine as a yacht tender and small recreational sailor.  When I say small, I mean small -- it's only 7'7" long.  Still, it has very nice lines, is easy to build and, if stretched out, is not too dissimilar in shape to the Jewelbox.  Also, I was familiar with the design and the glued lapstrake construction technique, having built several scale models of the Nutshell Pram as childrens' rocking boats and as baskets and display models.  Why not put Michalak's cabin on Joel White's hull?  

   view from the front

I increased the Nutshell's dimensions pertaining to length by a factor of 2.4 and those pertaining to width by 1.8.  This gave me an 18' hull that was just under 8' at its widest point.  Next, I made a 1/8 scale model, from which I have taken all my dimensions for the real boat.  Here it is:

Arcebus: the model.  
It's kind of hard to see in this picture, but I'll have a landing craft-type fold-down ramp in the bow to help get in and out of the boat when beached.

Construction

Sails
I finished the model in January 2003 and started right away on the mainsail -- a good mid-winter project.  I used Michalak's sail plan, which calls for a balanced lug sail of about 160 square feet.  He provides all the guidelines needed for broadseaming and shaping the sail.  The biggest challenge was to lay it out and sew it within the confines of my smaller-than-sail-sized living room.  I had to keep rolling it up one way or the other as I worked on it.  I found it was a lot easier to get 22' of rolled-up sail material through the sewing maching by ramping it down the stairs, through the sewing machine, and onto the piano and a lineup of chairs.   This gave me enough floor-area to get the whole length through in one pass and also gave me a little bit of an assist from gravity.  My long-suffering wife, Pam, was very anxious for me to complete this stage of the project.

I'm hiding in the shadows of the stairway in this picture

As shown on the model, I'm planning to experiment with adding a mizzen sail in the back.  Ths will give me a little extra sail area for light breezes and should help provide better balance.  The center of lateral resistance (pivot point) is going to be further back than it is on Jewelbox because of the different hull shape.  The mizzen will also make it a lot easier to handle the large main because it will help me face upwind when raising or lowering sail.  I already have a 60 square foot sail and mast left over from an earlier boat building project (Phil Bolger's Gypsy) which should serve nicely as a mizzen.  I think I've worked out pretty well the location of the combined center of effort of the sails and the pivot point of the hull.  I may be in for some surprises, though, so I'm planning to leave a lot of room for adjustment in mast angle (rake) and leeboard location.  The biggest concern I have is whether the boat will be able to stand up to that much sail.  My attitude is I'd rather have too much than too little.  I can always reef down and even if the boat gets knocked completely down it will not fill with water.   (If all goes as hoped, it will also be self-righting.) 

I've decided, too, that I'm going to use two pivoting leeboards instead of a single one as Michalak uses.  Arcebus has a much narrower bottom than Michalak's flat-bottomed boats and is going to heel over more when it's sailing.  I'm worried that a single leeboard won't have enough submerged area when it's on the weather side and the boat is heeled.  This could really be a problem if I need to get away from a leeward shore.  Also, having 50-60 pounds of weighted leeboard always hanging out on the windward side is ideal ballast which should help it stand up to the wind and contribute to self-righting capability.

Mast and spars
Michalak's plans call for a solid mast built of laminated 2 X 4s.  I decided to do it the easy way and use a tree.  A few years ago, a stand of spruce at my mother's lake place fell victim to the spruce beetle.  I chopped down the nicest looking ones and put them under the cabin to dry.  I hauled one home this spring.   At 22' in length, it's straight and weighs 30 pounds.  It's just under 4 1/2" at it's widest point and tapers to 2 1/2" at the top.  I glassed the top 3 feet for added strength.  In a balanced lug rig, the peak of the sail is supported by a top yard and extends much higher than the top of the mast.  I made the 12' top yard from some Sitka spruce offcuts I still have from a catamaran mast I built 20 years ago.  My 14' boom is from an old Douglas fir stair rail that I've been saving.

Lofting    
Lofting is the process of drawing patterns for the molds around which the boat is built.   Having already built a model, I simply scaled everything I used for the model up by a factor of 8 and drew patterns on a sheet of plywood.  Thank God for the metric system -- will we ever get smart enought to make the conversion?
Of course the problem with scaling up is that a measurement error of 1 millimeter on the model translates into an error of 8 millimeters in the full-scale lofting.  I was prepared to have to do a lot of shimming and trimming when I set up my molds and fit my planks, but was pleasantly surprised to find that no adjustments were necessary.   

Flying Boat Shelter
Since I was building the boat in the back yard, I needed a shelter from the rain.   I came up with what is probably the simplest and cheapest possible  type of structure -- a tarp suspended between two trees.  It has kind of a "no visible means of support" look since the 1/8" cable that suspends it is hard to see.   The cable runs through a sandwich of two 20' 2 X 4s in the area of the tarp.   Unfortunately, during a spring snow storm with sustained 40+ mph winds, a turnbuckle hook straightened out and it all came crashing down.

        

I replaced the turnbuckle with a rope and pulley system at each end so that I can lower the shelter in high winds and subsequently weathered many storms and two Minnesota winters with no further problems.

Building Jig and Frames
I set up the molds and transoms on a strong-back made from two 20' 2 X 10s.   Except for the dimensions, the set-up is exactly the same as for the Nutshell Pram.   (Complete plans for the Nutshell Pram were published in Wooden Boat in 1984, volume 60.)  The bow and stern transoms were made from 2 X 6 cedar boards, which I edge-glued with splined joints.  The middle frame is a permanent one (made of 2 X 6 cedar with heavy 3/4" plywood gussets) but the other two are temporary.    Two permanent frames were added after the planking was glued on -- one to serve as the front cabin wall and the other to serve as the rear cabin wall. 

Planking
The planking is plywood -- 2 layers of 1/2" on the bottom, 1 layer of 1/2" for the garboards (the first planks up from the bottom), and 1/4" for the top two planks, the topmost of which also forms the cabin walls.  The extra strength and weight below will provide impact resistance and (I hope) self-righting ability.   I spent less than $400 for the plywood in this boat.  It took 8 sheets of 1/2" lauan plywood at $30 per sheet and 16 sheets of 5' X 4' X 1/4" "Baltic Birch" at $8.88 per sheet.  I bought all of it at Menards.   All pieces were 5-ply, void free, had excellent faces on both sides, and were glued with exterior glue.  The birch, which is sold as underlayment, will be beautiful in the inside of the boat.  Birch has little rot resistance, but every piece I use will be covered with glass and epoxy, and will be above the waterline.  It is tough stuff, with beautiful faces that need very little sanding and no patching. 

Those sheets of plywood had to become long planks.  I used Dynamite Payson's method of scarfing -- butt joints held together with fiberglass tape.  Lay out some wax paper, wet down a 2-3" wide strip of fiberglass on the wax paper with epoxy, lay down the plywood so it butts in the middle of the strip, apply epoxy and fiberglass to the top of the joint, cover with wax paper, and apply weight to spread the epoxy out and get the the edges of the planks are in the same plane.  Here is a picture of the first bottom layer of the boat after applying tape and epoxy.  I have placed just about every heavy object I can get my hands on over the joints.   Because of the number and length of the joints here, I only did one side at a time.

Carrying the finished panel

Spiling the Planks
Spiling is the process of creating planks that are the exact shape that are needed.  After attaching the full-sized bottom and laminating another 1/2-inch layer on top of that, the edges of the bottom were trimmed to size and beveled to provide a gluing surface for the next planks (the garboard planks).  Below to the left is a picture of my pattern for the garboard.  The pattern is easily made with two battens (long thin strips) and cross-hatched bracing.  After fabricating one set of planks, the pattern is dismantled and rebuilt to match the shape of the next plank.   In this type of construction, the edge of each plank is beveled to a knife edge and serves as a gluing surface for the next plank.  The picture on the right shows how the pattern was constructed for the top-most plank.  A small electric bad gun was very helpful for attaching the cross-bracing.  Wherever I lapped two 1/4-inch thick planks on this boat, I backed up the joint with a 3/4" X 1 1/2" battens, which were let into the molds and notched into the transoms.  This increases the rigidity in the long spans between frames and to provides added gluing surface for greater strength.  

I glued the garboards on immediately after fabricating them, but the top two planks were only temporarily fastened.  After building and fitting them, I removed them and glassed them on both sides before gluing them on permanently.  It is much easier and cleaner to sand and glass them when they are lying flat on saw horses than when they are hanging on the hull.

Xynoling the Bottom
Instead of using fiberglass on the bottom and the garboards, I used a fabric called Xynole (also known as Dynel).  Xynole is made of a polyester and is much more abrasion-resistant than fiberglass.  I used two layers on the bottom and one layer on the garboards.  The bad thing I discovered about Xynole is that it sucks up epoxy like a sponge.  I felt like my budget was going to go through the roof.  I'm going to end up using about 11 gallons of epoxy for the whole project at $65/gallon -- definitely the most expensive item in the boat.  I will have a strong bottom, though, with a full inch of plywood and about 3/16" of Xynole/epoxy.  Xynole sands poorly, but I discovered that you can easily shave off any overlaps or high areas with a sharp block plane and it doesn't dull the blade. 

Here I am pouring more liquid gold into the black hole

Timeout for a Wedding
Not much boatbuilding for awhile -- my beautiful daughter Krista is married in August.   It was a wonderful wedding!

        

Building the Permanent Frames at the Cabin Ends
Before I could attach the top plank (which includes the cabin sides), I had to build in the permanent frames which are located at each of the cabin ends.  Doing this in the upside-down boat was the most difficult and putsy part of the project. 

Power Plant
I have two back-up plans for when there is no wind.  The first is a long sculling oar called a yuloh.  The yuloh has been used for thousands of years in the far east.  The long blade stays parallel to the surface of the water, but because it is beveled on top, it supposedly develops lift like an airplane wing when sculled back and forth.  It may be simpler to say that the angle of the blade makes it want to dive down when pushed sideways through the water, but it is restrained by the rope that runs from the end of the oar to the boat hull.  The downward thrust is, thus, transferred into forward thrust which propels the boat.  The thrust is continual as the oar wiggles back and forth without the slowdown that you get between strokes in rowing.  Some yuloh references on the web suggest that you might get close to hull speed under good conditions. The picture below is a shot of yours truly navigating across the dining room table in the model Arcebus.   

My second back-up plan is an old 5.5 horse Evenrude that I'll keep in the stern storage compartment for emergencies.  That should be enough to maintain hull speed in just about any conditions.

(That was my original concept -- the picture below flash-forwards 2 years to show the curved yuloh that I actually installed which allows me to operate it within the cabin.   I found the little curved tree for the shaft while canoing in northern Minnesota.)

Ready for Turning
As of September 4, the bottom is painted and the boat is ready to leave the security of its building jig.   Here's what it looks like:

Turning it Over -- Saturday morning, September 5
My long-suffering wife, Pam, does the heavy work.  I do the precision work.   Actually, this was a pretty easy 1-man job with a couple of car jacks and a stout rope wrapped around a tree to control the landing.  Glad I had the foresight to attach 8' 2X4s to the legs of the jig when I built it.

Examination by my long-suffering wife, Pam
You said this had a cabin.  So where's the bathroom?  Where's the kitchen?  Where's the standing head room?

   

She brightens up after a few lies.   Yeah, and I'm almost done, too.
 

A figurehead might be a nice touch                        Bon Voyage!                                    

Annika and Camilla (grandkids) are ready to go sailing

By the end of September I'm realising that it's not going to make it into the water before next spring.  I thought for sure I'd be farther along, but what with the wedding and other responsibilities, weekends and the odd Friday just weren't enough to get it done in one summer.  It's getting too cold for gluing and the days are getting shorter.  If I'm lucky, I'll get the roof and the decks on before the snow flies.  If not, I'll just cover it well and finish it off in the spring.  Gee, that gives me the whole winter to plan some cruises. 

October 9 -- An unheard-of 3 consecutive October days of 80 degree weather inspired me to put down 3 coats of epoxy on the floor.  Now I don't have to worry if I get a little rain water or snow melt in the inside.  The dark mahogany color of the garboards make for quite a contrast with the birch planks above. I selected the lighter lauan below because of its interesting grain pattern. 

Time to hang it up until spring of 2004
As of November 11th and I closed the book on Arcebus for the year to tackle the long list of honey-dos that Pam has let me avoid for so long.  I've got the decks framed and have spiled and cut out the panels for the cabin roof.  The picture below shows how the fold-down ramp and step-up at the bow are going to look.

One more thing -- I found a trailer!  Took a drive in rainy mid-November to the the biggest new and used boat dealer around and found the perfect trailer for Arcebus for $300 (it pays to shop in November).  This is one solid trailer, with just enough width between the fenders.  Yippee!

That's all until springtime -- thanks for visiting.

Second Summer of Construction.  No, I didn't finish it then, either, but I came close.

E-Mail me, if you like.