Collisions between non-powered recreational watercraft (kayaks, canoes, paddleboards, etc.) and faster, wind or motor powered vessels can be catastrophic for passengers in the slower vessel.
Any boater experienced with congested waterways is likely aware of the threat of a collision, but prior to 2012 almost no scientific research on the topic had been published.
Recreational boaters and professional mariners alike often share anecdotal advice on boating safety, but that guidance can be of mixed value, and lacks scientific merit.
In 2012, Robson Forensic published research that quantified factors in small boat collisions such as visibility thresholds and boater actions that influence visibility.
This article provides an overview of that study, discussing the relationship between speed and visibility in small craft collisions, known danger zones, and provides tips for all vessel operators to reduce the likelihood and severity of marine mishaps. The complete study can be accessed here.
Large Vessels Need Time & Space to Change Course
Seconds can make the difference. Visibility weighs heavily.
Operator inattention and improper lookout are leading factors in marine accidents. These factors can be exacerbated by a vessel operator’s inability to see and identify a small craft in the water in time to make evasive maneuvers.
For the operator of a powered watercraft to take evasive action to avoid a collision, they must first detect and then identify the presence of the non-powered watercraft. Visual detection and identification must take place at a sufficient distance to allow the operator of the powered watercraft to alter their course, or take other appropriate emergency action to avoid the collision.
Recreational boaters should be aware of the conditions that may diminish their visibility, traffic patterns that put them at risk, and what they can do to make themselves and their vessels as conspicuous as possible.
Mishaps most frequently occur when non-powered craft encounter faster moving vessels, such as speed boats and personal watercraft. With speeds often between 20 and 60 knots, it is practically impossible for the non-powered craft to maneuver its way out of a collision.
Identification Distances & Enhancements
This study revealed typical identification distances of a very small non-powered watercraft in the range of about ¼ nautical miles (506 yards).
- View Against Background: The study revealed that a very small craft viewed against a shore background affords the operator of the powered vessel an additional 15% (greater than 100 yards) identification distance when compared to an open water background.
- Fluorescent Attire: A conspicuity enhancing fluorescent shirt affords the powered vessel operator an additional 7% (approximately 50 yards) identification distance.
- Paddle Flash: Generally, study participants first saw “paddle flash” – reflection of the wetted white surfaces of the paddle between strokes.
- Audible Signals: Audible signaling devices such as marine whistles and air horns can have effective ranges of up to one NM, but the occupant of the non-powered craft typically does not and cannot know if they are seen by the approaching vessel.
At a closing speed of 30 knots, it may be impossible for the non-powered craft to take adequate avoidance measures. Any measures that can enhance your visibility to the approaching vessel can make the difference between a collision and a harrowing near miss.
Zones of Vulnerability
With typical identification distances in the range of ¼ NM, there are many circumstances in which a non-powered craft can be suddenly revealed to powered watercraft, similar to a pedestrian “darting out” between parked cars and into oncoming vehicle traffic. Such circumstances occur when the small craft is obscured by: peninsulas, islands, larger craft, blind bends, piers, or docks.
Prudent course planning by the non-powered watercraft can avert certain vulnerabilities. Based on the results of this study, while a small craft is better detected against a land background, there is a point where traversing too close to shore can place the non-powered craft into a Zone of Vulnerability.
There are also conditions where a non-powered vessel would take so long to cross a channel that it could unexpectedly find itself in the path of a faster vessel.
In short, any existing conditions that mask key identification features of the non-powered watercraft will negatively affect identification distances. Most participants identified paddle flash as the first visual cue. However, wave conditions, white caps, and frequent wave reflections can mask paddle flash. This can be overcome by raising a paddle and intentionally flashing by simultaneously waving and rotating the paddle. The use of dark colored paddle blades is not suggested as it results in less reflection from the sun, thereby reducing the beneficial effects of paddle flash on detection and identification distance. The ability to identify a small craft over open water is made even more difficult when the small craft is between the approaching vessel and the sun.
Recommended Actions for Non-Powered Watercraft
The following recommendations provide small craft operators with a greater likelihood of avoiding a collision. These are suggested for inclusion in boater safety and education.
- Carry required safety equipment including audible signaling devices;
- Wear fluorescent attire;
- Hug the shoreline except where you can be quickly unmasked;
- Preserve maximum sight lines;
- Understand implications of your speed, the speed of other vessels, time and distance to shorten your exposure and minimize collision risk;
- Maintain a visible presence through paddle flash;
- Use paddles with white or light colored blades (e.g., yellow);
- Cross perpendicular to traffic when crossing a channel;
- Be cognizant of prevailing traffic; put yourself where powerboats are less likely to be;
- Be mindful of and do not place yourself in Zones of Vulnerability; and
- Do not hesitate in using simultaneous audible and visual signaling to make your presence known to approaching powerboats.
Recommended Actions for Powered Watercraft
Powered watercraft operators should be educated about the following safety factors for avoiding a collision with a non-powered watercraft:
- At 30 knots, a power boat has 30 seconds to react to the presence of a non-powered watercraft at the average identification range;
- The powered watercraft operator must keep an alert and proper lookout. This includes listening for audible signaling devices;
- Powered watercraft operators need to be aware of the Zones of Vulnerability;
- Increasing speed decreases reaction time;
- Be aware of the value of sunglasses and binoculars;
- Environmental conditions may require extra vigilance; sun glare can hide small craft or mask the paddle flash;
- Expect the unexpected;
- Do not let activities such as stowing gear, hauling in fenders, tending lines to be a distraction; and
- The use of alcohol slows reaction time and hinders detection and identification distance.
Click here to access the full study.
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Bart is President/CEO of Robson Forensic, Inc. and also heads its Marine-Industrial-Specialty Practice Group. A testifying expert himself in matters of marine and mechanical engineering, he held advanced Merchant Marine licenses and is a licensed Professional Engineer over 20 states.
Having enjoyed a 30+ year career specializing in the unusual, Bart regularly analyzes catastrophic marine and industrial incidents, particularly involving machinery, systems, rigging and marine towing. As an International Association of Marine Investigators certified marine investigator, and having completed a 40-hour course in Marine Accident Investigation by the World Maritime University, he applies principles of marine and mechanical engineering to reconstruct marine casualties.