Diving from a charter boat can be a lot of fun and it’s a great way to reach sites that aren’t accessible from shore. Planning a trip aboard a dive charter is easy. Simply make a reservation, arrive at the dock on time, and you’re all set. The captain and crew are there to welcome you aboard. They take care of the boat handling, navigation, and dive planning, all while seeing to it that you and the other passengers are enjoying a safe, fun adventure.
Taking the helm of your own boat is also a lot of fun, but the “responsibility meter” rachets up by several notches, especially when you add a few sets of dive gear and some friends to the plan.
This article offers a very basic overview of what you’ll need to consider before planning a dive trip from a private vessel.
First, and foremost, diving from a private boat means you’re pretty much on your own. You’re the captain, divemaster, deckhand, navigator, entertainment director, you name it. Safe boat handling, even without diving, shouldn’t be taken lightly. While a piloting license isn’t currently necessary in California (see below), you need to know the basics of knot tying and line handling, boat operating, anchoring and docking. Like driving an auto, practice and knowing at least some of the “rules of the road” are also required. Make sure you are comfortable with your boat handling skills before you begin planning dive trips.
As a boat owner/operator it’s your responsibility (and legal duty) to ensure the safety of your passengers. They need to be given a pre-trip briefing that includes an explanation of boating safety, where the life preservers are, where the first aid kit and fire extinguisher are stowed, and more. When adding all the extras involved with scuba diving that list grows considerably. Things like where and how to store gear, entry and exit procedures, anchoring and/or live boating (drift diving from an unanchored boat) procedures should be discussed before embarking.
Most fellow boat owners I know have made at least some modifications in their vessels to make them dive-friendly. The biggest changes are usually made to facilitate entering and exiting the water. Very few boats are designed with scuba diving in mind, and as such, may be quite easy to get off but quite a different beast getting back on, especially if one is cold or weather has kicked up. Not all boats are alike; for example, I have a 24-ft. Rigid Hull Inflatable (RIB) that’s super for diving from but can be a challenge to get back into. To outfit my boat for diving, I learned that a custom-built ladder was a necessity. 
Besides the normal boat safety gear I strongly recommend carrying supplemental oxygen. Divers Alert Network (DAN) is a good source for both equipment and training. While all boats need a good first aid kit the diving boat should have a few extras in it as well. Sooner or later someone is going to get stuck with a sea urchin spine. Once spines have been removed very hot water is the preferred treatment – if it’s available. Unfortunately, on many small boats, it isn’t so make sure to add vinegar to the kit. Even rubbing lime juice on the punctures will help with alleviating pain and dissolve spine fragments. It works on sea jellies, too. Other specific safety gear should include a buoyant current line and float, as well as a diver down flag and a means to prominently display it.
Arguably, effective navigation is the single most important skill needed as a boat skipper. Granted, global positioning systems (GPS) have made the job almost too easy; electronics do fail and having a rough idea where you’re located at any given time is a good backup. Paying attention to compass headings, time of departure, running time, and speed is important. This is all part of piloting. Using landmarks, aids to navigation, and water depths all help determine where you are. It’s a good idea to study a coastal chart(s) of the areas you plan to do the most diving. Passing on at least some of this info, like which way is home, to a passenger can make for a better day too.
Rules of the road aren’t something to take lightly. Several thousand boat-to-boat collisions occur in U.S. waters annually. The biggest cause is “improper lookout” or “other vessel/operator at fault.” The U.S. Inland Navigational Rules  and California Boating Law and the Harbors and Navigation Code concern us the most. Both local Harbor Patrols and the Coast Guard can enforce these requirements both in fresh and salt water. There are far too many to go into detail here but most come down to common sense; keep a lookout, maintain a proper speed for conditions, and realize that even if you have the legal right-of-way when meeting a 20,000-ton freighter, claiming that right may not be in your best interest. Before you set out on your own, make sure you spend time with a knowledgeable boat operator who can act as a mentor. And even after you’ve gained some experience serving as a deckhand for someone else, consider enrolling in a boating skills course.
Besides carrying marine insurance on your boat, some kind of emergency care plan is good to have, too. It’s similar to a roadside assistance policy for your automobile; in the event that your boat’s engine fails and you need to be towed back to port, an annual policy will save you a fortune in towing fees–and it buys valuable peace of mind knowing who to contact if you run into trouble. Companies including BoatUS 360 Boating and Sea Tow offer 24/7 assistance.
There are plenty of “don’ts” — things to avoid doing — when it comes to safe boating. For starters, as the person responsible for the boat and its passengers, don’t even think about consuming alcohol while on the water.
And don’t gamble with dicey weather conditions. Be informed on weather and diving conditions before making a go/no go decision. The National Oceanic & Atmospheric Administration (NOAA) and National Weather Service (NWS) have a number of websites and other free useful information. Ask the locals at your dive center and marina or boat launch about the weather and conditions, too.
Santa Ana or Santana easterly blowing winds are one of the near shore potential problems. These winds can be extremely dangerous 30-50 miles out. In fact, in 1939, forty-five boaters drowned, mostly coming back from Catalina, by an especially severe blow. Fortunately, these winds are fairly easy to predict, but it’s important to pay attention to the weather several days in advance.
Another big force to reckon with is the large numbers of cargo ships that ply the nearshore waters. They usually use the Northbound and Southbound Coastwise Traffic Lanes; essentially yet another freeway of the southland. The roughly four-mile wide passage is located between the California mainland and offshore islands. Northbound vessels cruise closest to the mainland with about a two-mile separation zone between them and the southbound lane. Maximum speed is 10 knots. These large vessels create a very large, steep wake, so stay alert. Both the travel lanes and the maximum speed limits are recommendations only, so expect the unexpected and you won’t be surprised. Long Beach and Los Angeles Harbors (by numbers of containers) is the busiest port complex in the U.S. On a typical 25-minute crossing to Anacapa Island, I’ve seen as many as six ships within several miles of us.
While anchoring in the thick of a kelp bed can be done, it’s a good way start the dive off on the wrong fin. Having heavy strands around the boat almost guarantees diver entanglement, both on entering and getting back on. Also, trying to retrieve the anchor can quickly turn into a massive tug-of-war and the kelp usually wins. It isn’t very environmentally friendly, either. Instead, always try to drop the anchor in a sandy area near the kelp bed, not in it. Not only does the Danforth (a type of fluked anchor) dig in quite well, it also can be recovered with a minimum of effort or seabed disturbances.
Diving from your own boat is a lot of work, but it can be very rewarding, too. Your own time schedule, dive sites, extended marine mammal interactions, and picnics in a kelp bed, are just a few of the perks you’ll get in return for the extra preparations. 
Currently there is no mandatory requirement to possess a boating operator’s license in California, unless you’ve been convicted of a moving violation on the water. However, taking the on-line test for the Boater Education Certificate is a good idea and may well lower your insurance premiums.
California “Official” Boating and Safety Course (fee required but ID card given)
California “Official” Free Boating and 
Safety Course (free but no ID card)  
California Division of Boating and Waterways (main source of CA rules/regs) 
U.S. Coast Guard online Rules of the Road
Coastal Data Information Program 
(swell model chart)
National Data Buoy Center (NWS forecast)
Chapman Piloting Seamanship & Small Boat Handling 
(book recommended by the  Coast Guard Auxiliary) 
The Diver Down Flag
California boating laws are still vague about minimum distances other boats should maintain from a diver down flag. Currently, the closest language specifying distance says, “An operator is guilty of a misdemeanor if [traveling] at a speed in excess of 5 mph in any portion of the following areas: Within 100 feet of any person who is engaged in the act of bathing….” Local municipalities may also have their own take on dive flags and other rules. In other words, do not assume that other boat operators know what a diver down flag means or what to do when they see one.