FPB 70 Bow – Taking Metal To New Levels Of Shaping Sophistication

FPB-70-Bow-shape-1-of-31_comprsd

The FPB 70 brings together the very best of everything we’ve learned in the last 40 years, not the least of which is a very sophisticated bow shape – perhaps the most difficult plating job ever.

FPB 70-1 is shown above between FPB 78-2 and 78-3 (assembly of 70-2 starts shortly, when 78-2 launches).

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The key to going comfortably upwind, at normal cruising speed, is a bow fine enough to pierce waves, while at the same time with sufficient buoyancy to begin lifting smoothly as larger seas are encountered. And it must be easily steered when surfing at high speed.

This is a shaping issue we have been resolving for the past 40 years.

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If you look closely, you will see the forward sections off the bow are hollow above the plating edge. What this does is allow the bow to penetrate more easily into small to medium size waves, like those associated with trade winds when your destination is directly upwind. The reserve buoyancy desirable in larger seas comes on further up the topsides. These hollow sections transition to a  positive shape at an appropriate distance aft of the bow providing additional buoyancy for larger waves..

Creating this shape with metal, smoothly, was heretofore considered impossible.

Of course all of this relates to the stern sections, but that is another story.


Posted by Steve Dashew  (January 24, 2017)




6 Responses to “FPB 70 Bow – Taking Metal To New Levels Of Shaping Sophistication”

  1. Henry Says:

    Steve,

    It’s a little difficult to tell exactly from the photos, but the forefoot looks fairly deep compared to earlier bows, particularly Windhorse’s.

    Is the forefoot brought right up to the bow or is it pulled back?

    How do expect broaching to be affected?

    Steve Dashew Reply:

    The forefoot depth and cross section are related and this plus the slenderness ratio just above the floating waterline is more knife-like than in the past. The closest FPB would be the FPB 78. Rudder size is slightly larger in scale as well. We think steering characteristics will be comparable to other FPBs.


  2. Andy Says:

    Fascinating metalwork, and efficient looking shape. Almost reminds me of airliner wing and wingbox, before they started making those out of plastic that is… Btw very interesting article on bowshapes: “Hiswasymposium 19: The Axe Bow: The Shape of Ships to Come by J.L. Gelling”.


  3. Peter Bateman Says:

    Those are some very fine craftsmen who can work that plate over that non compound curve. It is a bow shape that is so totally logical but extremely difficult to plate up. The hours that this will take will be appreciated on every large wave your bows progressively lift out of.


  4. PJ Says:

    FPB Ark.


  5. Shannon (Shaz) Says:

    When I was a kid in the 70’s, my grandmothers friend was a metal former in WWII. She continued it as a hobby & in the 70’s she made some of the coolest stuff out of aluminium. She made kids pedal car bodies & some art kinda things. It takes a real talent to roll out complex shapes. I know, I tried. I got the crashed aircraft shape down pretty well. lol
    No doubt, having to deal with large, heavy plate makes it much more difficult.