Review common questions about shallow water boat handling, end swapping events, testing standards, and related safety concerns.
What is an end swapping event?
An end swapping event occurs when a boat enters into a turn and loses its ability to maintain steerage contact with the water and in some cases violently spins out.
What types of boats are prone to an end swapping event?
First and foremost are boats specifically designed for shallow water fishing. The majority of these boats are mostly flat-deck with little or no gunnels or railings and in general seating for two at the operating station.
Does the hull design make a difference?
The hull can be modified “V” or flat; all generally will have a tunnel in the aft 1/3 of the hull. Their chines can range from hard to curved. Most are equipped with jack plates to assist in running in shallow water.
What are some common names used for the style of shallow water boats prone to an end swapping event?
Texas Flats Boats, Texas Flats skiffs, sled boats, and Tunnel Vee Boats.
What loading conditions make an end swapping event more likely to occur?
The potential for non-oscillatory dynamic instability, such as “swapping ends,” increases when the longitudinal center of gravity is forward, which can occur when one or two passengers or other weight are situated forward of the console.
Does the depth of the water in which the boat is turning have an effect on the possible end swapping event?
Yes. It is well known that a boat’s performance changes as you go into shallow water. Generally it runs at a lower trim angle. At the present time we don’t have any test data or any design methods to actually account for this.
Is there a specific speed that makes an end swapping event more likely to occur?
Our testing has shown that an end swapping event is possible at speeds as slow as 25 miles per hour.
What standard was used to test boats for an end swapping event?
After looking at several potential protocols it was determined that the Quick Turn Test out of the ABYC’s H-26 Powering of Boats standard was most appropriate.
Were any of the end swapping tests conducted during rough water conditions which may cause a flats boat to flip over and capsize?
No. All tests were conducted on calm water with the wind speed below 10 mph, or 9 knots.
Are these evaluatory efforts being directed entirely at outboard powered boats or are inboard powered boats also being evaluated?
We only evaluated outboard powered shallow water boats.
What is a boat’s maneuvering speed?
A boat’s Maneuvering Speed is the maximum speed at which the boat is capable of completing the maneuvers required by the ABYC H-26 Powering of Boats standard.
Does the quick turn test address the safe powering capacity that was previously calculated by weight?
The quick turn test as outlined in ABYC standard H-26 is a maneuverability test. One of the issues is that some of the flats boats manufacturers have requested exemptions from the maximum horsepower requirements in the regulations and we’re using the quick turn test as an alternate method to make sure that the boat can handle the horsepower they install. H-26 requires that boats that go over 30 miles per hour perform the quick turn test to determine the boat’s maneuvering speed. It’s a method of making sure those boats can be handled appropriately with the recommended maximum horsepower.
Has there been any recommendation to establish a maximum engine horsepower on shallow water boats including Texas flats boats?
Not all shallow water boats are constructed the same so it is not possible to pick a specific speed and say it is hazardous. As our testing has shown, a swap end event is possible at speeds as slow as 25 miles per hour. In light of this information the Coast Guard recommends that manufacturers and importers of flats boats determine Maneuvering Speed of all boats and advise their customers accordingly.
Do traditional Personal Water Craft have a problem with end swapping?
Earlier models of PWCs tended to have a problem with end swapping because they had a rounded hull, but the later design of hulls with more of a V-shape resolved this problem. They can still end swap but normally you would have to intentionally make the PWC do that.
Will the Coast Guard pursue further federal requirements or leave it as a recommendation?
The Coast Guard does not have authority to regulate boat designs but does have the authority to identify substantial risk defects. The Coast Guard is working with as many vested equities as possible to try to increase awareness to the boating public, boating organizations, and boating manufacturers.
Will the Coast Guard grant an exemption for powering to allow larger horsepower engines if the manufacturer proves that the model boat will pass the ABYC turn test?
Yes, if the manufacturer is able to show that the boat can pass the H-26 quick turn test and be operated safely at maximum speed with the size of the horsepower engine onboard.
What is the process of having your boat certified via the standard?
Manufacturers may self-certify to the ABYC H-26 standard just as they do to the Federal regulations in 33 CFR 183.
If a manufacturer is ready to have their boat tested for an exemption on safe horsepower capacity, who would be the point of contact?
Every manufacturer has a factory inspector that works for us in your region. The easiest thing to do is to contact the Recreational Boating Safety Product Assurance Branch. Depending on where your manufacturing facility is located the responsible factory inspector will give you a call or may come out and discuss.
What sized skegs were used during testing?
We actually installed two different sets of skegs and they varied. There was one set that was approximately 72 inches long and 4 1/2 inches deep. The other set was much smaller at 18 inches long and 4 inches deep. We were looking at two different approaches. We wanted to make sure that the really long skegs would definitely work and whether smaller ones would also work. The intent is not for us to tell the manufacturer how to build their boat. It is to give them some tools and ideas. Whatever the manufacturer chooses to do, the quick turn test would provide the manufacturer a mechanism to evaluate their boat.
Are any manufacturers acknowledging this safety issue and installing skegs to vessels already on the market?
Unfortunately we cannot speak to this. Outreach activities to the manufacturers have included providing boating safety circulars directly to the manufacturers, conducting webinars, posting information on the website, and working with other boating safety partners to get the message out through their networks.
Do you know of any manufacturers who intend on selling these skegs as after market?
The Coast Guard is not currently aware of any such activity by any manufacturers.
If there are boats with unpredictable end swapping, why are they not being recalled?
The Coast Guard has regulatory authority to test manufacturers’ boats with respect to buoyancy, fuel system, electrical, power, ventilation, and lighting. The Coast Guard does not have regulatory authority for hull design regulation. When a substantial risk defect is identified under authorities the Coast Guard has, the Coast Guard may ask or, if necessary, direct manufacturers to recall unsafe products.
Have shallow water boats including Texas Style Flats boats been determined to be manifestly unsafe?
These boats are not manifestly unsafe for the purpose of what they are designed for. They are fishing platforms designed for shallow water fishing. If they are operated in a manner that does not lend itself to the end swapping event occurring, the platform is an acceptable platform. When variables come together, including operator input, forward velocity, and water sea state, they can lend themselves to a swap end or hull skipping incident.
Is there a warning label to let me know that my boat’s maneuvering speed is less than the max speed?
If your boat is capable of a top speed of 30 or more miles per hour, or 26 knots, using the manufacturer’s rated power and is certified using ABYC standards, then there will be a warning label when the maneuvering speed is less than the max speed.
If a mechanism was designed to reduce throttle when steering input exceeded a certain degree, would that qualify for the quick turn test?
From a standards perspective, the test is performance based. How the manufacturer completes that is up to the manufacturer to determine. The question is whether the wheel can be turned 180 degrees and held for a 90 degree turn and have the boat successfully complete that turn.
Has there been any research into bow structure and design in relation to end swapping?
The bows are not standard in the industry. Some flats boats have very deep V bows and others have very shallow V bows. Research suggests that a deep V bow makes more side force at the bow than a shallow V. That means a hull with a very deep bow is more likely to be directionally unstable than a hull with a shallower bow.
Are there existing ABYC standards regarding railings, side seat restraints, and similar features?
ABYC has two standards. One addresses railings and it is H-41. The other standard addresses seat structures and is H-31. Most of these types of boats are considered open boats, so they are not necessarily required to have a railing structure around them, but they are required to have a handhold for each designated occupant.
Would it be feasible to install restraint systems like a seat belt for passengers in these types of boats?
Currently there is not an ABYC standard for restraint systems. Although a harness system was installed on the operator to mitigate hazards during testing, a safety boat was nearby in case of capsizing or other unforeseen event. The most desired situation would be that the boats would not have this tendency to end swap. ABYC standards require a designated occupant position with a handhold for each occupant in the boat.
Could a video be produced that a customer would be required to view and sign in acknowledgement?
This is a great recommendation. The Coast Guard has no authority to mandate either manufacturers or retailers to comply with this recommendation. Manufacturers and retailers have a vested interest in their customers going out, having fun, being safe, enjoying the water, and returning safely. Manufacturers and retailers should seriously consider it as part of their marketing and product differentiation efforts.
Are there efforts to expand Coast Guard regulatory authority over hull design?
The Coast Guard does not have a legislative change proposal submitted at this time seeking to expand its regulatory authority to address hull design. The statutes that authorize the Coast Guard specifically empower the Coast Guard to provide only minimal safety standards.
Can the states regulate hull design?
The states generally do not have authorities that the Coast Guard has preemptive authority over. The Coast Guard does not have statutory authority to regulate hull design.
How does the Coast Guard keep track of boat manufacturers?
Boat manufacturers and importers are required to obtain a Manufacturer Identification Code, or MIC, from the Coast Guard. The Coast Guard tracks boat manufacturers by their Manufacturer Identification Code.
How does the Coast Guard inform the boating public about news and information of interest to the boating community?
The Coast Guard periodically publishes Boating Safety Circulars. Boating Safety Circulars are available on the boating safety website.
What specifically is the Coast Guard doing to ensure that manufacturers and importers receive Boating Safety Circulars?
The Coast Guard pushes the Boating Safety Circulars out to all registered manufacturers. Boating Safety Circulars are also available on the boating safety website.
Where can we send the public to buy and install skegs if they want to minimize this type of hazard?
The Coast Guard recommends that you contact the manufacturer or local dealer of the boat or seek the advice of a marine surveyor prior to making any modifications to your boat. The manufacturer is best able to provide guidance on if and how modifications to your hull should be completed.
Has the issue of end swapping already been the subject of a Boating Safety Circular article?
There have been two articles on this issue. One appeared in the October 2014 Boating Safety Circular, issue number 88. Another appeared in Boating Safety Circular issue number 89.
How many deaths can be attributed to an end swapping event?
There have been three fatalities over the five year period from 2010 through 2014 that can be attributed to an end swapping event. There were 3,800 fatalities in total over the same time period.
Should I include a photo with my float plan?
Yes, it is recommended that you include a photo of your vessel. Just like with luggage, many boats look alike, so a photo will help responders identify your boat.