New Tilting A-Frame for Osprey Vipermax

[Richard Selman]

Just arrived from Mark at Marine Fabrications in Staffordshire.

Started this nearly 18 months ago. It needed to be able to tilt forward so that I could still get the RIB into the garage and also it needed to curve out over the transom to leave space for the aux. Since I would not be able to get the boat to the fab shop I knew I would have to get all the curves and angles right (hence the 18 months!).

I first got Mark to make me up the lower support arms so that I could fit them to the boat and then have four points on a plane to draw up the rest.

Had to remember how to do trigonometry calcs again.

Also made a prototype with waste pipe.........

[Richard Selman]

the finished article is somewhat nicer to look at.

Along the top I got mark to weld on two Shakespear type aerial mount ratchets, a threaded socket for a reflector, a flag pole holder and a threaded GPS mount. No clamps.

Also two cleats built in. There are two nice light holders for LED lights that came separately.

[Richard Selman]

Closer view of mounts.

Forgot to ask for mouse wires to be left in. Have some work to do to run the cables.

[Downhilldai]

Looks good. How much?

[Richard Selman]

Rear attachment arm.

There are two hidden M12 bolts into the tube as well as the M12 U bolts

[Richard Selman]

try again

[Richard Selman]

Front attachment arm. No hidden bolts this time as I needed to flex a little to reduce the load on the transom boxes. Osprey provides a nice chunk of ply in the front of the boxes to mount onto.

The radius had exactly the VMs tube diameter to look right. Mark did not have the exact formers to do this so it was finished in the rolling machine. This indented the tube exactly where the flanges on the transom boxes were and made it a uniform clearance around the rube and makes it look spot on.

[Richard Selman]

A frame in place....

[Richard Selman]

A frame tilted forward

The frame height was set to just clear the seat backs. The aerial attachment points are set so that they clear the backs as well so the aerials can point forwards between the seats and tubes.

[Richard Selman]

moment of truth........