Boat Construction - | Bill's Boat Works - Ferro Cement Construction | Ken Adkison

www.adkison.name

Wed, 11 Apr 2012 16:34:05 -0700

Photo Album

Tue, 20 Dec 2011 06:28:27 -0700

Structural -

Mon, 04 Jul 2011 12:50:30 -0700

Photos are chosen to illustrate construction methods but are of boats

Plastering Day -

Sun, 03 Jan 2010 18:41:33 -0700

Gimbal Hull

Mud (two sand, one cement plus a little acid to control ph and limit corrosion) is pushed through the wire until air is driven out.

Then after it starts to stiffen slightly, back plastered from outside. This sets the bulk of the material in the wire.

As work moves along we knock most of the mud back off just barely down to the wire with a trowel. This takes off weight and prepares the outside surface.

The inside also gets stripped of excess and we fill anything missed up to this point.

Back over the whole exterior with a skim coat to provide the final finish while controlling the final thickness. The skim coat has to set a while prior to finish work.

Timing is everything as the crew works around the boat areas become ready for the next operation at different times. A great plan and experience really help but in the end someone has to be the boss and direct the work. This is dad's boat, so as on the sea, the captain is the commander and has to push the crew hard to keep things moving fast enough to outrun the setup times. Things always go wrong; mud too thin, setting up too fast (or slow), flat exhaustion, wire problems, frustration and even worker revolts – rare.

Most of the crew is done for the day as soon as the tools are all washed down.

A quick pass with a wet float a needed to help smooth and establish shape.

Troweling and shaping continue until it is fully set and nothing else can be done; late into the night.

The last and very important step is to cover the hull with burlap bags and/or old blankets and set sprinkler hoses all around it. The idea is to keep the whole hull wet for a month. This will slow the final setup of the cement and make it much tougher.

Of course I am writing this from memory and will accept corrections and alternative methods. Not many folks have had a chance to do this kind of work so I thought it best to share, before I forget.

Variations -

Sun, 03 Jan 2010 18:11:57 -0700

Gimbal proved to be an excellent comrade in many an adventure

Optional reading - Variations in building techniques:

Inverted construction - Having seen this done, I don't favor it. This allows a platform providing stability, puts the difficult back plastering on the inside and allows drainage. Turning was a most daunting task that damaged the boat somewhat.

Wooden Rib Formers - Used to stabilize, generally inverted, hull until plastering is complete. While this sounds like a good idea, we have proven it unnecessary and a whole hell of a lot of work. After flipping the hull all the wood must be removed and the area in contact with the hull ground down and back plastered.

Up-right method - Dad came up up with the following scheme: Two very stout overhead beams are erected over the sides of the hull. All ribs are hung from this using steel rod drilled straight though as nearly all the hull's weight will be suspended from it wen done. This is critical because the keel mast be plastered from the bottom. Once done the sailboat moving company can push the trailer straight under it.

Plastering in sections - We plastered two hulls this way to split the very difficult plastering into multiple days. This works, but I am personally not convinced that is a good idea. Advantageous in time, number of skilled craftsmen needed and the ability to get plaster and people in and out of the hull right up to the final plastering day, straight through the unfinished hull! Disadvantage is the risk that the hull may not be as strong (unproven).

Ferro Basics -

Sun, 03 Jan 2010 08:23:11 -0700

Stages of hull construction (details follow)

Very few rules be set in concrete here - methods and opinions differ wildly

Pipe a or heavy rods are bent to that shape of each rib

All ribs are hung at their respective stations

Steel rods are strung and welded along the bottom and top of the ribs to lay the keel and establish the cap rail along the edge of the deck.

A number of 3/16" rods are stretched around the ribs as a temporary guide to judge the lines of the hull.

This is the last chance to make changes to the shape of the hull.

At this point the additional steel is added to keel for strength around the keel. The deck is outlined, ribbed and gusseted in steel. The fiddle head, engine mounts, transom, scuppers are added.

3/16" cold rolled steel is welded on every 2-3" horizontally from the cap rail to the keel.

Much thought and work goes into insuring all aspects of the final completed boat are accounted for by the armature built up to this point. All hard mounts, plumbing, rigging and anchor points should be accounted for.

Hardware cloth (steel mesh) is stretched over the exterior and interior tied on every three inches. This works like fiberglass to provide a strength bearing binder to the concrete (resin). Everything is steel up to this point, the shape can, and most, be worked until it is perfect. Prior to plastering the armature should be so tight that it will nearly ring like a bell when hit.

Plastering day - All work leads up to this 30 hour day. The wire skeleton must be right, the shop cleared of everything not related to plastering and enough tools assembled for a large crew. Scaffolding is made ready to reach every part of the boat. Everybody has to come on site fed and ready to start. Once the mixer is started only two breaks are available until the whole boat is floated and trawled to final finished. The number of workers drops off near the end but it is a big day.

Composite Hull -

Sun, 03 Jan 2010 08:03:39 -0700

A Comparison of boat hull construction materials

Wood is excellent historically proven and sturdy, but is expensive and time consuming to build and maintain.
Fiberglass is also excellent, sturdy and has reduced labor costs when built in quantity. The material is somewhat expensive. The downside is home builders will have to build the boat twice; first the mold then the boat.
Steel and aluminum is best used for larger boats and ships as is very hard to make compound curves at smaller scales.
Ferro-Cement materials are quite inexpensive though requires more labor for a good result. The big advantage is how easy it is to make any shape without a mold. Built correctly the resulting hull is very thin, strong and easy to maintain even in saltwater!

Dad completed three of these sailboats and all proved very seaworthy and quite tough. We would regularly tack along leading edge of storms, under full sail, dipping the deck in the water just for the fun of it, without problems. Our boats were never going to win races with the featherweight fiberglass racing hulls, but they sailed beautifully and we got positive comments everywhere we went. Dad stylized them as “character boats”, warm, comfortable and with room to sleep aboard.

Built with a full keel, we were able to withstand a few hits, rocks and had other misadventures that could have finished off lesser boats. We rarely suffered any damage.

Masts and Spars -

Sun, 03 Jan 2010 07:33:19 -0700

Masts and spars can be created at home using a 40' profile cutting horizontal milling machine with a cylindrical cutting attachment. Sound expensive? Figure on 400 bucks. These photos show what my dad (Bill Adkison) could with a little Yankee know how.

This requires a cutter to move radially around tree and down it's length while following a fixed taper schedule. A router will cut wood, a tree can be put on rotating centers like a corn cob and the two can be held in proper relation by holding the router on a base that can follow boards set at the right height and angled to the required taper. This is an example of working a problem from the end result backward from first principles to satisfy minimal requirements to the job. We end up with a well suited custom tool that after completing it's task, can be taken back apart and almost all the parts made available for other duties.

Building Tool

Seasoned and debarked tree gets pinched between to stable points so that it can be turned by hand.
Planks are supported alongside tree to form a table around 5” below the trees center. Multiple planks are cut for each section of taper (more later).
Router is laid sideways and a base made to hold it stiffly horizontal while sitting on a board. A piece of wood attached to the back edge of the board furthest from the bit to act as a guide. Now the router can be slid along the plank and shoved up to the guide block there by limiting the height of cut and the rough depth of cut while allowing the whole affair to slide along the length of the tree.
Boards with rollers can be rotated to act as guides and clamped or nailed into place to keep the mast or spar from bouncing.

Using Tool

Plan out taper profile and replicate it in planks. Mast diameters may start out 4” at the step (keel) and be 5” at the deck, then taper slowly until the last third then drop to 2-3/4 at the mast head (made up example). You'll need to cut and support the plank at each change in taper or just saw the edge to the profile intended.
During roughing, The planks are set so the router and plank combination can, at full extension, reach into the tree no closer then 1/2” from the final intended mast size taking into account the intended tapers.
The router is now started and slid into the tree until the guide hits then the tree is rotated by hand until a slice goes around it. Do this every three inches or so, then use a hatchet to knock out the uncut areas in between (as a rule work toward diminishing taper).
Reset the planks to take the first shaping pass. Run the router closer to the final diameter and turn the mast. Move it a bit and keep going until the entire mast is uniformly tapered and round. BTW - This may take many days and a number of passes.
Finish with a fine cut to just about the final diameter. Buy sandpaper in rolls. Wrap a 7’ piece of coarse sand paper around the mast once and holding one end in each hand start dragging it back and forth. Work from end to end rolling the mast as needed to finish it up. You’ll get tighter shirts this way.

Boat Construction - | Bill's Boat Works - Ferro Cement Construction | Ken Adkison

www.adkison.name

Photo Album

Bill Adkison

Gimbal 20'

Gimbal

Capella 27"

Hairy Tate's 32' 'Myterti'

Jesse and Mike Truax's Boat

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IMG_0164

IMG_0088

IMG_0043

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Structural -

Modeling concept

Laying Keel

Ribs

Hang Ribs

Armature

Plastering Day

Respected Friends

Bow

Curing

30-days wet

Done

Plastering Day -

Variations -

Ferro Basics -

Composite Hull -

Masts and Spars -