TWIN OUTBOARD MOTOR BRACKET
First and foremost the boat transom must be properly prepared prior to installing the outboard motor bracket. It is strongly recommended that a professional fiberglass boat repair facility be contacted to close the outdrive cutout and / or repair or replace any rotten wood found in the transom. Additionally, if the strength of the transom is in any way questionable, an additional three-quarter inch sheet of properly fiberglassed - in plywood should be installed across the inside of the transom. Other reinforcements may be required or recommended by your fiberglass boat repair facility, especially if twin V- 6 outboards are to be installed. The boat owner / operator is responsible for ensuring that the boat is properly repaired and prepared prior to installing the outboard motor bracket.
TWIN OUTBOARD INSTALLATION:
The Following Assumes 25" Shaft Motors Set at 28" centers!
For 20" shaft motors deduct 4" off 24" and 28½" all other measurements stand!
Measurements following the preceding illustration are performed at the location where the twin motors intersect the transom. Typically, the centers of twin V-6 motors are located 14" outboard from the centerline of the keel ( 28" center to center ). Measure from the boat bottom using a framing square and mark the transom at 24" at both locations (See figure 1&3). (Don't forget - you are measuring 14" outboard from the keel centerline left and right.) Install the top forward edge of the twin bracket at these marks, centered with the keel and level on the boat transom. The top of the motor mount should measure 28½" +/- ½" above the bottom of the boat where the motor intersect the transom. (Again, you are measuring 14" outboard from the keel centerline SEE FIGURE 2&3.) It is strongly recommended that you check this measurement before drilling bolt holes in transom because this is the MOST IMPORTANT bracket height. With engines installed, the outboard motors anti-ventilation plates should measure about 2½ inches above the bottom of the boat.
After water testing, the motors maybe raised, using the installation bolt holes on the motor mounting plates if a higher installation offers better handling or performance. The above motor height measurements are a recommended beginning point. Individual boat hulls have different performance characteristics and some may perform better with the motor raised an additional two or three inches. Achieving optimum performance is usually obtained by trial and adjustment.
MOUNTING THE BRACKET:
It is recommended that ½ inch stainless steel bolts be used when installing the bracket. Bolts should be installed every 10 to 12 inches depending on bracket size. The Rockwell Outboard Motor Bracket is not predrilled, the owner / installer must determine where to drill the bracket and boat transom. All holes drilled through the boat transom and the bracket to boat seam must be sealed using a below the water line marine sealant (i.e. 3M 5200). Additionally, it is recommended that aluminum plate or channel be used on the inside of the transom to ensure the strength of the installation. D&D offers an installation kit containing either 4" x 4" x ¼" aluminum plate or 4" channel (as specified) and necessary hardware.
!! Remember !!
If you have any question or doubt of what you should do, or how to go about installing this bracket. PLEASE CALL !!
We will help with any questions.
© 1996 D&D Marine Distributors