I. Swim Categories
A. Marathon swim
A swim that follows the traditional rules of marathon swimming, which have remained in large part unchanged since 1875, when Capt. Matthew Webb first swam across the English Channel. Swimmers are permitted to wear a standard textile swimsuit, one standard cap, goggles, ear plugs, a nose clip, and grease. Artificial aids – which are considered to be anything that improves speed, buoyancy, or heat retention – are prohibited.
B. Assisted swim
Any swim in which the swimmer wears or uses artificial aids of any kind, including non-standard swim caps (e.g., bubble caps or neoprene caps) and standard non textile swimsuit (e.g., wetsuit or stinger suits). Assisted swims are not eligible for course records or “firsts.”
II. Swim Rules
These rules will be read aloud by the observer before every swim attempt.
A. General Rules
- The boat captain has the ultimate authority on the boat. (S)he may call off a swim at any time because (s)he perceives that anyone’s safety may be in jeopardy.
- The observer is in sole charge of interpreting the rules during a swim. (S)he may call off a swim at any time because of failure to comply with the rules or danger to the swimmer. Failure to follow the observer’s instructions by the swimmer or any support person will result in disqualification.
- If the swim is called off by the captain or observer, the swimmer must immediately exit the water.
- The swimmer is permitted to wear one standard swimsuit, one standard cap, goggles, ear plugs, a nose clip, and may grease their body.
- The swimmer may not use or be assisted by artificial aids of any kind. This includes, but is not limited to, swim fins, webbed gloves, body tape, a watch that receives and displays GPS data, a metronome or pace keeping device, audio players, or streamers (lane lines).
- During the swim, the swimmer may not make supporting contact with any person or object.
- Paddlers are allowed. Support swimmers are allowed as long as they are not in the water for the entire duration of the swim.
- The swimmer may not intentionally draft off either the escort boat, paddler, or the support swimmer.
- The swimmer must start from one natural connecting shore, standing above the water line, and finish on the opposite natural connecting shore, above the water line.
- The timing of the swim starts when the swimmer enters the water and ends when the swimmer clears the water. The observer is the single official timer of the swim and will record the official time in the observer notes.
- No alcoholic beverages may be consumed by anybody associated with the swim or the escort vessel, from dock to dock.
- A swimmer must not take any drugs that are on the U.S. Olympic Committee's list of prohibited medications.
- The swimmer or crew may not intentionally pollute the ocean with trash or debris (including but not limited to feed cups and gel packs) at any point before, during, or after the swim, from dock to dock.
- The swimmer or crew may not intentionally harm any wildlife at any point before, during, or after the swim, from dock to dock.
B. Double/Multiple Crossings (click to expand)
- Each single crossing (called a “leg”) must conform to each of the General Rules above.
- After completing one leg of a multiple-crossing by clearing the water, the swimmer must re-enter the water to begin the subsequent leg (if applicable) no more than ten minutes later.
- During this time between legs (the “interlude”), the swimmer may be handed food, medicines, swimming apparel, and grease, but (s)he cannot be touched by anyone.
- The elapsed time of the swim continues running during the interlude.
C. Relays (click to expand)
- A relay team may be comprised of two or more swimmers.
- The relay must designate a crew leader. The crew leader is not allowed to swim.
- Each relay member shall swim for a set time period – called a “leg” – each time he or she enters the water. The team shall choose its own leg duration, but it must be the same for each swimmer, and must remain constant throughout the duration of the relay.
- The order of rotation must remain the same throughout the duration of the relay.
- Swimmer exchange: The new swimmer must approach the preceding swimmer from behind, pass him or her, and touch hands above the water. The exchange must not exceed five minutes.
- A relay team may substitute an “alternate” in place of a core team member, provided: (a) the alternate was listed in the original application, and (b) the core member has not yet entered the water to begin a leg. No more than two alternate substitutions are allowed. (This circumstance may arise if, for example, a team member fails to show up at the dock, or a team member becomes sick or otherwise disabled on the ride to the starting point.)
- Any relay member who has swum any part of any leg is not eligible to be replaced with an alternate.
- If any swimmer exits the water before his or her leg is completed, or does not enter the water when his or her leg is scheduled to begin, the relay is disqualified.
- If a relay is disqualified, the swim is over. Swimmers must exit the water immediately, and the escort boat must return to the harbor.
D. Assisted swims (click to expand)
- Assisted Swims must conform to all of the above-listed rules, with the exception that the swimmer is permitted to wear a swimsuit and cap of any material, thickness, and coverage.
III. Clarification of Allowed Swimwear and Devices
This section applies only to Category A (marathon) swims.
- Swimwear / costume
- For men: One porous swimsuit made from textile materials, which does not extend below the knees or above the navel. Jammer-style suits are permissible.
- For women: One porous swimsuit in one or two pieces, made from textile materials, which does not cover the neck, extend past the shoulder, nor extend below the knees.
- In general, these guidelines are equivalent to those for FINA pool competition.
- Swim cap: standard-style, constructed from latex or silicone. Not allowed: neoprene caps, multiple caps, caps with chin straps.
- Any device or apparel that improves speed, buoyancy, or heat retention other than the standard items listed in Section II, Rule 4 is considered to be an artificial aid and is prohibited.
- The swimmer may not use or be assisted by artificial aids of any kind. This includes, but is not limited to, swim fins, webbed gloves, body tape, a watch that receives and displays GPS data, a metronome or pace keeping device, audio players, and streamers (lane lines).
- If the swimmer is uncertain whether a device or apparel item is allowed under these rules, he or she should seek clarification from the MBSA well in advance of the swim attempt.
IV. Mandatory Pre-Swim Requirements
If any of the following pre-swim requirements are not met, the MBSA reserves the right to cancel the swim attempt (with refund of fees according to the schedule published in the Swim Application).
- A complete application package, along with requisite fees, must be received by the MBSA at least 60 days before the swim attempt. (
- Solo swimmers must demonstrate sufficient open water marathon swimming experience to justify their planned attempt. This information is provided in the “Swim History” section of the Solo Application.
- It is solely the swimmer’s responsibility to arrange the dates, meeting times and departure times with the escort boat and to communicate this information to the observer and support crew.
- Observer assignments. The MBSA will assign an observer to the swim attempt. Swimmers are not permitted to assign observers. A swimmer may request an observer, or request a change in observers, and the MBSA may accommodate these requests at its discretion.
- Communication with observer. Within three weeks after a Swim Application is accepted by the MBSA, the swimmer (or relay) will receive an email identifying the assigned observer for the swim. The swimmer and observer(s) are expected to be in communication with each other at least 30 days before the swim attempt (contact information will be provided in the email).
- Escort boat and pilot:
- Capacity. The escort boat must be large enough to accommodate the swimmer, observer(s) and support crew. It is the swimmer’s responsibility to determine the boat has sufficient capacity before booking. Keep in mind, the swimmer counts toward this capacity even if he or she is in the water.
- License. The escort boat must be licensed with the U.S. Coast Guard, and a copy of this license must be on file with the MBSA.
- 12-Hour Rule. According to the USCG “12 Hour Rule,” a commercial boat captain may not work for more than 12 of any 24 hours at sea, except in an emergency when life or property is endangered. If the escort pilot is a commercial captain, and the swim attempt may last more than 12 hours (dock to dock), it is the swimmer’s responsibility to ensure there is a second licensed captain aboard the vessel. Note: If the escort pilot is not a commercial boat captain, this rule does not apply.
- Familiarity with rules. The boat pilot must be familiar with MBSA rules. If a pilot has not escorted a MBSA swim before, (s)he must confirm in writing that (s)he has read and understands the rules.
- Support crew. It is the swimmer’s responsibility to recruit a support crew capable of handling feedings, paddling, and other needs of the swimmer. The observer’s job is to observe only, not to act in a support capacity. If the support crew is more than two people, it is recommended to designate a crew chief.
V. After the Swim
- Finishers certificates and awards will be handed out at the end of the season awards ceremony(most likely sometime in late October or early November.) If you cannot attend, your certificates and awards will be mailed to you.
- Swim ratification: Within 2 weeks following a successful swim observed by MBSA, the observer logs and report will be available and the swim is ratified. For any swims that may have been completed prior to forming the MBSA, you may submit copies of your observer logs, a detailed report of the swim, and written confirmation of the swim by your pilot and crew (witnesses). Additional evidence may be requested by the MBSA at its discretion. Once recognized, the swim is added (in chronological order) to the ongoing list of swim successes in the appropriate category.
- Assisted swims will be recognized in the appropriate category, but will not be eligible for Records or “Firsts.”