Building the "PLUG" - THE CRUCIAL PART

BUILDING THE PLUG - THE CRUCIAL PART
      By Pat Brandlmayr

"The term "Plug" is a word that is not used much unless you are talking about boats from earlier days, or boats that are built with the same values and traditions as those earlier days.  In a discussion with our Patricia Brandlmayr, this topic came up.  She explained the procedure in an understated way, but you can imagine the meaning of the term "quality control" when you think about the procedure."
       
Here is Pat's explanation to this topic...

"Yes, it is difficult to use precise terminology in the development of a product from concept, to finished product - partly because there are different ways of approaching the project.  In the case of Spencer Boats the process was initially a 3-step process to reach the molded fiberglass hull. "

1. To build a wooden structure the exact shape of the finished product using wooden construction materials (which varied over the years) in an upside down position - as you would to build a one-off wooden boat. This object would be faired, and then coated with fiberglass/resins, which in turn were sanded, sanded, and sanded again, as the applications progressed to produce an object which would replicate the final product.
2. The mold would be produced by means of suitable overlays on the plug, reinforced by means of a structure to keep its shape and to stand the production methods for the fiberglass hulls.
3. The mold is then lifted from the plug, turned over or upright and the inside of it fine tuned for the production of the first fiberglass hull. The condition of the mold will, of course, reflect how good the final product or fiberglass hull is. The fiberglass hull for the first boat is then laid up for production. In the case of Spencer Boats, the bulkheads, tanks, longitudinals and the deck were all installed prior to lifting the hull from the mold. Although this tied up the mold in production longer than for most production boats, it also insured that the product would not warp and get out of alignment.
   

It was only the 1330 where the plug was constructed using "one-off fiberglass construction methods" to build the plug from which the mold was taken. The technologies had changed in the interim years and this was a logical way to go at the time. This "plug" was highly finished on the outside and it was completed as a boat for Harry Herlihy and became Hull #1 - Benora III. (Note: This boat is now named "Trinity" as of 2010 - SYOG)

In the case of the 42/44's the mold was built with the topside extended to the sheer height of the 44 in order to accommodate the requirements for the center cockpit configuration and layout. The mold, in other words, had the option of the 42 lower sheerline or the 44 higher freeboard and sheerline.

In all cases the deck molds were made starting with a separate wooden plug from which the mold was prepared for the molding of the decks. Prior to designing the 42 footer, John did a good deal of preparation. He studied the lines and performance of the Annapolis 44 which was a popular classic boat at the time. Prior to production of the boat, tank tests were performed at a testing tank in the States.  I don't know if this helps clarify terminology and production sequences that apply to the way things were done at the Spencer yard at the time.  Since all the boats at the time were laid up by hand, I am sure current technology and high production has changed many things.


Cheers!

- Pat Brandlmayr  via e-mail Nov 3, 2004