Casting the Ballast Keel

Please view the first entry in this blog if you are a potential buyer of our boat.  Photos and specifications, along with contact info is in the entry titled: Sale Sail Sale Sail Sale Sail.

Present circumstances:  1-15-15

Varnishing that mast.  Richard put the eleventh thin coat of varnish on the mast today.  He is very particular about his varnish, believing that it's the best protection for the wood.  Since varnish doesn't have reliable UV resistance, he will give the mast its final coat in paint.  But that's probably 10 sunny days away!  

Lower tang, port side (left); upper tang, port side, with staysail halyard attachment point (right).

Boatyard workers and resident cruisers stop by to check on Captain Baila's progress every day; and every day he has to recruit someone to reposition the blocks when he lifts and turns the mast. In another port, another marina, there might be a painting pro he could trust to do the job?  Not too likely.   
On rainy days he's inspecting the rigging, and has found so far one swage that will have to be redone where 2 of 19 strands of steel in one cable have failed.  

Who knows if Abrazo's new owner will appear this spring?  For this boat owner, diligent maintenance means the boat is always ready to go to sea.  

On with the origin story ...

A quick summary: 
In September of 1979, my brother Ronny came out from Pennsylvania to visit us.  We put him to work as we drove from one auto service station to another, collecting the last two thousand pounds of wheel weights we needed.  

Towards the end of October, 1979, we returned from a deer-hunting trip to find that the plans from Argentina had arrived in the mail, at last!  We butchered the deer, wrapped and froze the meat, and then Dick took the drawings to the loft floor and went to work.  By the end of November he'd built a wooden mold for the ballast keel, and we'd filled it with lead.  

For Christmas, that year, I wrote the blow-by-blow, highly dramatized version of the Lead Pour Story for the entertainment of my family back in Pennsylvania.  You'll get a more straightforward version here, in a minute.  The reason I mention the Christmas version:  it inspired my father to send us a book - The Autobiography of Benvenuto Cellini.  Dad had marked Part II, section LXXV, in which Cellini recounts his blow by blow, highly dramatized report of the casting in bronze of his magnificent Perseus.  Great fun to read.  Online version   Cellini pursued completion of his artistic creation with all the same intensity and vehemence as Dick Baila did.

October, 1979:  Lofting the boat

Lofting per Wikipedia is a drafting technique that generates curved lines for building aircraft and boats. In the case of a wooden boat, the lines are transferred to wood pieces for additional shaping. The boatbuilder bends a batten, a long strip of thin wood, so that it passes over three non-linear points, and then scribes the resultant curved line onto a pattern, or directly onto the plank or board he wants to shape.  Those three non-linear points come from the Table of Offsets provided in the boat's plan.  In 1979, you marked the measurements from that Table of Offsets onto your loft floor to create a full-sized drawing of the boat.  Nowadays, your computer-generated shaping programs deliver the patterns. 

Having worked nine months at Boeing, building pieces for the wings and interior spaces of the 737 aircraft, Baila had a variety of experience with patterns for curved shapes.  With a little help from his boat-building mentor, Bill Modrell, he lofted the new boat quickly, and moved on right away to building a mold for the ballast keel (Quilla de Lastre).  

From the plan above you can see that the keel is 4.65 meters in length, a little more than a half meter deep, and almost a third of a meter wide at the widest point.  Metric!  Baila claims it is so much easier to work in metric than in feet-inches-eighths. 

Campos estimated the weight of the keel at 3200 kilograms.  He would have cast the keel in iron (hierro), but we know, for one thing, that lead is better at resisting corrosion.  In the Puget Sound boat-building community back then, lead was the best choice because you could cast it yourself.  You didn't need to pay a foundry.  

What about the weight differences?  Iron weighs 475 lbs/cu ft, while lead weighs 710 lbs/cu ft.  Using lead, we need to change the volume of the designed keel.  How to do that?  Today you can go to The Wooden Boat Forum to read the blah-blah-blah of opinions on this question.  Center of buoyancy, center of gravity, righting moment, etc.  Wikipedia covers all the aspects of a pendulum's swing wiki/Pendulum, if you can imagine the boat as a pendulum with the ballast keel as the weight of the "massive bob" and the top of the mast and the "frictionless pivot."

Baila consulted with his mentor, Modrell; and recalculated the volume of lead with his engineer father.   He built the mold for the ballast keel to be a few inches less deep than designed, and planned to make up the difference in deadwood.  

November, 1979:  Casting the lead keel

He used 3/4" plywood to build the mold, and coated the interior surfaces of the wood with "waterglass" aka sodium silicate, a passive fire retardant.  Many thanks to the engineer at the local Georgia Pacific Pulp Mill who was willing to contribute a quart of waterglass, used as a peroxide stabilizer in the bleaching of pulp, for our project.  

Baila and our hired friend, Jay Taber, dug a pit in the gravelly clay soil of the yard, and positioned the keel mold below the drainpipes from the bathtubs in which the lead would melt.  (Same plan as Cellini used for his bronze statue.)  They mounted the bathtubs on stacks of cement blocks with space underneath for the propane torches.

Taber, at left, digs more scrap out of a drum.  Baila, center, and your reporter, right, skim slag.

On Thursday, November 29, 1979 we started with a single torch under each tub, and began adding in those clunky wheel weights and irradiated cylinders.  The day turned colder by the minute, wind blowing right into the yard.  Dick went out and rented three more torches and propane tanks.  I began to bank up a wall of mud, using the muck they'd dug to make the pit, to keep the heat underneath the tubs.  Wish I'd read Cellini before we started, because he knew this at the start!  It was those mud walls that turned our torches into a real furnace.

The melting point of lead is 620+ degrees.  Once the dark and dirty grey chunks began transforming into a silvery puddle in each of those tubs, the slag ... stuff that is not lead ...floated to the surface to be skimmed out with a wooden paddle. As the silver pool in each tub deepened, each newly-added pound of scrap melted more quickly; but on that November day it took almost six hours for those five torches to melt our four tons of scrap lead.  

Baila had rigged wooden troughs with wire handles to guide the trickles of molten metal from each tub into the mold.

Campos' plan called for 9 bolts (bulones) of 36 mm diameter to hold the ballast keel to the boat.  Bill Modrell advised Baila to use wooden dowels to reserve space for these bolts in his mold.  Further, Modrell suggested hexagonal pieces of Douglas fir to represent the nuts into which those bolts would fasten.  Even painted with waterglass these nuts and bolts would turn to charcoal during the lead pour; but it would be much easier to drill out the charcoal than to drill through lead.   
  
Baila built "strongbacks" - clamps bolted across the top and bottom of the keel mold - to hold the shape against the weight of all that lead.

Our friend, Walden Haines stopped by at 4:30 in the afternoon and snapped these photos.  Shortly after that, boatbuilder Dave X from Blaine dropped by, to pronounce a lot of negative words about failed castings.  Three minutes after he left, one end of the mold gave way!  We lost about a thousand pounds into the trench before Dick could drive enough wedges to stop the leak.  With nothing left to melt that night, we had to shut down the operation.

When Cellini saw that he was short of metal for his bronze casting, he ordered his crew to collect all the household pewter: plates, bowls and goblets, and throw these into the melt. Baila had to pay a premium for the scrap lead he bought from local dealers next morning, but it would take an expert metallurgist with x-ray eyes to find a seam where the Friday morning pour bonded to the main body of lead in the mold. 

It was a few days later - the lead not yet fully cold - that a man on a forklift, after delivering machinery to the business next door, agreed to lift the lead keel out of the ditch with a chain.  Dick and Jay threw blocks in the hole to hold the lead above ground till they could position rented railroad jacks and maneuver that lead in space.  Once the hole was back-filled, Dick placed heavy "sleepers" across the ground, stable enough and leveled to support the building of the new boat.  He knocked away the remains of the wooden mold before setting that lead keel down again. 

Thanks to artist, Peter Fromm, for capturing this day's images.

A few months later, Baila would use wedges and levers to tip the keel on its side so he could bolt the "backbone" assembly to it.  Levered upright again, with the new boat's backbone securely fastened, the keel would not move again until launch day.  

In my Christmas story about the pour, I quoted Henry Thoreau ... the one about putting foundations underneath your "castles in the sky."  I'm sure Dick Baila never had any doubts about achieving his dream, but for me, that ballast keel was a superb anchor to reality: evidence that we really would be able to build this boat.