Page 20 - Masthead18

This is a SEO version of Masthead18. Click here to view full version

« Previous Page Table of Contents Next Page »

After watching the Wednesday night sailboat races with my family a few weeks ago, a sturdy-looking motorsailer steamed past us. It was dusk, and the disbanding racers and boaters were us-ing their navigation lights. As the mo-torsailer turned into the wind to wait for the drawbridge to rise, my dad men-tioned the boat’s stern light was out. The boat continued to rotate and we saw a flash of the stern light when his davit-mounted dinghy swung just enough to reveal the small-but vital- signaling device.

Certainly if the owner added the davits, the owner is responsible for recognizing the navigation light is now obstructed and he needs to relocate the lamp. Fol-lowing the requirements in the 72 COL-REGS and ABYC’s A-16, with few exceptions, navigation lights shall not

be obstructed throughout their arcs of visibility. What’s the big deal with blocking a little light? After all it’s con-sidered acceptable in North America to mount a bicycle rack on the trunk of a car and obscure the tail lamps and license plate. Why not on a boat? Should something go wrong, like a speeding powerboat running over a slower boat whose stern light is not visible, the slower boat could be at fault.

What does this mean for boat designers and builders? No you are not expected to predict all future owners’ modifi-cations to your design and construction. The aftermarket radar, spotlight, bimini, swim platform, dinghy, solar pan-els, flags, horns, and anchors are inevitable. Recognizing trends during the design and procurement phase can re-duce the need for additional rework when owners person-alize their boats.

Similar to the automotive industry prior to World War II, sourcing navigation lights involves opening a catalogue and buying off the shelf. Knowing this, boat designers and

builders should provide a location to mount the navigat lights. A flat pad parallel to the static waterline, the lon axis of the boat, or both will cover side and masthead lights. A vertical pad athwartships should be included o the stern or pushpit for stern lights. Masthead and allro lights on arches or hardtops should give extra height to clear future additions and avoid fold-down designs that commonly left at a raked angle. While this minutia may seem unnecessary, consider the distances involved. Na gation lights for pleasure craft can exceed a visibility of three nautical miles. If a sharpshooter’s rifle was off by seven degrees, would he hit his target? Making matters worse, boats are dynamic in nature and when underway even the best intensions for mounting can be compro-mised. The standards account for this provided the lam mounted correctly. Furthermore, due to the heeling of s boats, they have unique requirements for vertical sector intensity as in A-16, Figure 7.

Email: dcasali@abycinc.org 

Nav Lights: Small But Significant 

By Dante Casali 

Port sidelight obstructed dead-ahead by horns and antennae

Page 20 - Masthead18

This is a SEO version of Masthead18. Click here to view full version

« Previous Page Table of Contents Next Page »