FPB 64 Construction Update November 18, 2011


Since we’ve been boring you with technical posts all week why change the rhythm? These photos are from Friday, and cover FPB 64s five through seven. We’ll start with seven, shown above,¬† the skeleton of which is just starting to be assembled.


These structural elements are cut on a computer driven device that adds alignment marks for assembly as well. There are welding jigs for each of the prefabricated items, like bulkheads and tank tops, which insure accuracy and speed production.


All of this starts as a 3D model of the complete boat, which is then dissected¬† into cut files. The furniture is designed to fit this same 3D model, which minimizes fitting time (and mistakes). It is this potential efficiency, harvested by Circa’s experience in production, that makes it possible to build to such a high standard yet keep costs moderate. Absent this approach, the price at this quality level and specification would easily double.


Moving on to FPB 64-6, the metal work is nearing completion. We are looking here at the two prop skegs, main on the right and get home, framed but not yet plated, on the left. Both share the same framing and plating scantlings.


Inside the engine room, the prop shaft tube (log) for the get home engine. Note the sump, which slopes down towards the bow, and drains to the main sump. This detail reduces constant wetness from pooling of drips under the “dripless” shaft seal.


The house structure is now welded in place.


Note the structural connection of the house roof assembly. The corner and side window mullions are captured at the top of the coaming, at the deck, and then down the topsides with a partial frame to the upper topside stringer.


Finally, a series on FPB 65-5, starting with this look up at the headliner panel grounds (attachment points).


Looking aft towards the entry way and galley. The large locker at the top of the stairs, formelry for jackets and foul weather gear, is now dedicated to the galley.


The oven will live at the bottom, and then the rest is available for general storage.



Note the angled pipe in the pantry locker which goes to the exterior for mast wiring. The angle downward is to assist any drips in returning to their native environment, rather than visiting the interior where such malevolent entities are most unwelcome.


Bulkheads, furniture grounds, and what will become covers for structural members and raised deck edges are completed in the aft guest cabin. Note the aluminum cable trays. These will shortly be well populated.


And last, the get home engine with its V drive (bottom of photo), thrust bearing, and engine,

Posted by Steve Dashew  (November 19, 2011)

7 Responses to “FPB 64 Construction Update November 18, 2011”

  1. Richard Says:

    Care to share the production cost comparison with a heavily built mold tooled production fiberglass vessel of the same design? Bearing in mind that there are certain aspects of the design you cannot achieve with fiberglass, just as there is a different list of things that are impossible or more expensive in metal, I’d guess that the pure cost crossover point would come at about hull # 4?

  2. Steve Dashew Says:

    Hello Richard:
    For the FPB Series we do not think fiberglass can compete with welded aluminum in terms of tankage. Since this is a prerequisite of the design, your question really cannot be answered. The other issue is structure. Unless built carefully with lots of carbon, you cannot match the aluminum structure in fiberglass. Leaving aside these two fundamental issues, a production line fiberglass yacht of similar spec and quality would be maybe 25% less. But, this is meaningless since the design simply cannot be successfully built in plastic.

  3. Norm Moore Says:

    Steve, What remote v-drive.unit are you using on the get home drive?

  4. Steve Dashew Says:

    Hi Norm:
    It is a ZF remote V.

  5. Mike Says:

    Steve are you considering a folding or feathering prop for the get home engine? The idea of dragging a fixed prop everywhere seems unlike you.

  6. Steve Dashew Says:

    Hi Mike:
    The standard spec is a three bladed Gori folding propeller.

  7. Richard Says:

    Hi Steve,

    You may remember chatting in Seattle many years ago when I was PM for the build of an aluminum 112′ S & S motorsailor called the Venturosa? I agree that at best case the comparison with fiberglass construction is like comparing oranges to grapefruits. Hard to imagine achieving the degree of grounding damage survival of an integral tank aluminum boat with any fiberglass construction, and I don’t think carbon or kevlar would contribute much more than a deeper hole in the pocketbook.

    The advantages of fiberglass production mold tooling are economic and cosmetic. Once you paint aluminum and attempt to maintain it in perfect show condition over a number of years the cost factors move even further apart. I recently supervised paint touch-up work on a 155′ motor yacht that leaves it’s boat house for one week a year, and it still requires yearly attention. So in my mind the French & Dashew choice of bare metal is the only one that makes sense.

    ps. the photos you posted of zincs with virtually no wastage are impressive. Certainly puts the maritime myth of aluminum self destruction to rest!

    I usually close my letters to fellow sailors with the comment, “Fair Winds”, but in this case I guess that isn’t necessary!