Bertram 31 Side Opening Air Boxes

02/07/05 - Design Updates
To gain more engine room space, the original style dorade box has been discontinued and a smaller, but equally efficient, dorade box has been designed.

Bertram 31 Side Opening Air Boxes on "Buddy Boy"

Please Read Carefully before ordering any parts.

These ready to install Dorade Air Boxes, for side induction air are specifically designed for the Bertram 31. Principal features include:
Optimum air volume
Up to 400 hp diesel. Diesel engines need far more air than do gas engines. The rule of thumb for diesel engines is 1/2 square inch of free air delivery per each rated horse power at full RPM.  (Boxes are also available in any length from 12" to 66".)
Noise reduction
Air delivered from hull sides, below the shear line.
Cleaner air
Even in a head sea with smoky diesel engines, the inducted air is always fresh. No ingestion of engine exhaust, as is possible with cockpit air supplies.
Visual appeal
Form follows function. The three hole configuration is both a "signature" design, and a complement to the lines of the Bertram 31.
Price per pair: $1,700.00 plus packing and shipping.  (USA east coast shipments have averaged $125.00 using UPS ground.)

Minimum deposit required: $825.00

Shipping time: 4 - 6 weeks.

Kit will contain the following:

  • Port and Starboard Air Box Assemblies
    Each box has 3 elements:
    Primary Baffle Assembly - Will be bonded to hull.
    Secondary Baffle Assembly - Will be bonded to underside of gunnel.
    Dorade Box - Extends from bulkhead to bulkhead.
  • Template to cut side holes
    Can be used to either simply trace the holes to be cut, or as a router guide, (suggested).

  • Installation Instructions and tips

  • Technical Support: Via phone, email, or General Discussion Board. (Registered Members Only) ( )

  • Construction of the Air Box is 100% polyester resin and fiberglass. Installation should be done using epoxy resin and Cab-O-Sil. Addition of fiberglass mat or cloth as tabbing is not necessary.

    The Air Box and hole template have been designed to give optimum free air delivery for any engine up to 300 hp. Acceptable air delivery for engines up to 400 hp. Air delivery is calculated for diesel application, so any size gas engine is more than covered.

    More detailed installation instructions can be downloaded here...

    Bertram 31 Air Boxes - Side Inducted Air

    Clicking the thumb nail images will open a new browser with a larger image...


    For additional information, please contact:
    Capt Patrick McCrary
    834 Scott Dr.

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