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A Plane Affair
Posted: Friday, November 20, 2015 2:45 PM
Joined: 19/08/2014
Posts: 67

A new season, a new tender. The boss was in pursuit of the perfect ride ashore from 60-meter M/Y Slide. The last four tenders had fallen short of the mark, each being disregarded for a different reason; one was too small, another not feisty enough and the last one had lacked the required elegance. This one was black, beasty and guaranteed to make heads turn.  

Mate Dominic revved up the nine-meter, 300-hp beast and headed ashore to pick up the boss for the first trip of the season. He was relieved to hear her first words. “I like this one — sleek, powerful, elegant, like a panther waiting to attack. Show me what she can do!” Dominic attached the kill cord and pulled away from the dock, clearing the harbor before opening her up to three-quarter throttle, easily putting the tender on the plane. The boss was sitting in the aft seat, her hair streaming in the wind, contented as a panther after the kill. “Dominic, throw her around a bit. I want to see how she handles,” she directed. Dominic nodded and headed for a patch of clear water in sight of M/Y Slide

The water was like glass and there wasn’t a breath of wind, so Dominic thought he could take advantage of the conditions to impress the boss with some tidy maneuvers. He throttled back and played with the helm, throwing the tender to port and starboard as if on a slalom course and with each turn, the tender heeled pleasingly. Feeling confident, Dominic increased the revs and threw the helm hard over to starboard to make a tight turn. The boss let out an excited shriek, but Dominic sensed they were heeling too far over, the balance now on the inflatable fender. The hull lost grip and the stern slid abruptly to port, skidding across the water and dislodging the boss from her seat. The tender then violently righted itself and bucked the other way, port tube down. The boss was flung over the port side and into the water; the tender sliding over her. Dominic threw the helm to port as fast as he could to slew the propeller away from her, then killed the engines. Looking back, his heart was pounding, and he was shaking so much he couldn’t make sense of what just happened; it had only been four seconds since he put the helm over to make the turn. 

Making a tight turn at high speeds can cause a RIB to “hook” when the speed reaches its particular threshold coupled with the turning radius limit. If a turn is executed above the RIB’s thresholds, then the stern can lose grip in the water and slide, thus initiating a partial spin or hook (because the bow did not slide by the same amount) until the boat’s keel grips again and the sideways motion is suddenly stopped, causing the craft to roll violently upright from its heeled position. 

Dominic collapsed into his seat in shock as he saw another tender speeding over to help. The boss was floating face down, blood pooling around her body. As she was pulled from the water, unconscious, a large gash across her thigh was exposed, right down to the bone. The tender driver managed to resuscitate the victim and use his shirt to wrap the wound before meeting first responders on the dock. 

Most yachts require crew to have an RYA Powerboat Level 2 certificate to drive the tender, but is this sufficient training? “The Level Two course is a great introduction to powerboat driving and has been the benchmark for a long time,” says Dave Hartwell, principal at the Watersports Academy in Poole, UK. “However, RIBs are getting bigger and more powerful, and I think the advanced course should now be the requirement for driving more powerful tenders commercially. At the Academy, we teach mostly with a 225-hp engine, which does give a true likeness to the more powerful engines. …An engine of this size or similar should be used to do the training.” 

In addition to the driver being sufficiently trained, driving safely at speed relies on a RIB being well designed and tested. All recreational craft put into service in the European Economic Area must be built to the specification of the Recreational Craft Directive (RCD) and for some RIBs, this means conducting a maneuvering test. “Whether a maneuvering test is required by the RCD is a function of the length, breadth and weight of the RIB,” says David Greening, naval architect and RCD consultant. “If required, the maneuvering test must determine the maximal maneuvering speed for the RIB. One such maneuvering test is the ‘quick turn test,’ effectively completing ninety-degree turns to port and to starboard at high speed without the driver’s loss of confidence in maintaining control of the boat.” 

The RCD states, “If the maximal maneuvering speed is determined to be less than the top speed of the boat, a warning label containing the determined maximal maneuvering speed and the related information shall be posted on the boat.” 

“The weakness of the testing regime is that the test driver is allowed to practice in order to work up to higher speeds,” explains Greening. “Tests are generally carried out by very experienced RIB drivers who are familiar with demonstrating the product of their company and not by a novice driver, which may happen in the real world.” 

Dominic took a few months off work to recover from the trauma of the event; even so, he regularly experienced frightening flashbacks. Knowing the maximum maneuvering speed and handling characteristics for this specific RIB may have prevented this unfortunate incident. 

Posted: Friday, November 20, 2015 11:56 PM
Joined: 13/02/2012
Posts: 2

Sounds more like a design flaw to me. No vessel should respond to turns with such dramatic idiosyncracies!
Gabriel Poirier
Posted: Tuesday, November 24, 2015 5:37 PM
Joined: 21/05/2008
Posts: 31

In fact, “If the maximal maneuvering speed is determined to be less than the top speed of the boat, a warning label containing the determined maximal maneuvering speed and the related information shall be posted on the boat.” 

This is true. sadly, more and more tender have to powerful power plan combine with crew without the proper training and experience. I did work for an owner who put on an engine a way to powerful for the tender. The builder remove the brand name of the tender. This was a very dangerous situation. 

More training is needed for the crew. The RYA Powerboat Level 2 certificate is not enough for more and more tender. Also, with a serious lack of experience from the crew, this kind of situation is, I believe, happening more often.

I spend 11 months out of the year in different marinas and on a regular basis, I see "crew" without the proper experience to steer this kind of tender. A lot of them cannot dock in and out without hitting the dock or the yacht. They are going to fast inside the marina and obviously in the open sea. 

I think that some of them try to impress. Now ask to the crews who died last spring in the B.V.I. how they fell about it.

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