The number of lifeboats required on a ship depends on what kind of ship it is, but the underlying rule is the same across the board: survival craft must accommodate 100 percent of the people on board. For passenger ships, lifeboats on each side must cover at least 37.5 percent of everyone aboard, with liferafts making up the rest. For cargo ships, lifeboats on each side must each hold everyone on board, so the vessel effectively carries 200 percent lifeboat capacity. These requirements come from the International Convention for the Safety of Life at Sea (SOLAS) and, in the United States, are enforced through Title 46 of the Code of Federal Regulations.
Passenger Ships
Passenger vessels carry the most people, so their rules are the most demanding. Each passenger ship must carry a combination of lifeboats and liferafts with enough total capacity for every person aboard. Lifeboats on each side must have aggregate capacity for at least 37.5 percent of the total number of persons; liferafts served by launching appliances or marine evacuation systems, equally distributed on each side, cover the remainder.1eCFR. 46 CFR Part 199 Subpart C – Additional Requirements for Passenger Vessels
The reason for splitting capacity across both sides is practical. A ship listing heavily to one side may not be able to launch the lifeboats on the high side at all, so each side has to be capable of evacuating everyone on its own.
Passenger vessels on short international voyages that meet certain subdivision standards can reduce the lifeboat minimum to 30 percent per side, with liferafts covering the rest.1eCFR. 46 CFR Part 199 Subpart C – Additional Requirements for Passenger Vessels
Passenger ships of 500 gross tonnage and above must also carry at least one rescue boat on each side. Smaller passenger vessels need at least one rescue boat total. A rescue boat is a distinct piece of equipment: it is designed to recover people from the water and marshal liferafts, not to serve as a floating shelter.
Cargo Ships
Cargo ships carry far fewer people than cruise liners, but the lifeboat math per person is more aggressive. Each cargo vessel must carry lifeboats on each side with enough capacity to accommodate every person on board. That means the ship carries lifeboats for 200 percent of its complement in total. On top of that, the ship needs liferafts with additional capacity for everyone aboard, either stowed for easy side-to-side transfer or distributed on each side.2eCFR. 46 CFR 199.261 – Survival Craft
An alternative arrangement is common on modern tankers and bulk carriers: a single free-fall lifeboat launched over the stern, with aggregate capacity for everyone on board, plus liferafts on each side also sufficient for everyone.2eCFR. 46 CFR 199.261 – Survival Craft Free-fall lifeboats drop from a stern ramp and hit the water at speed, which makes launching possible even when the vessel is listing badly or the seas are rough.
Smaller cargo vessels under 85 meters (about 278 feet), excluding tankers, get a concession. They can substitute liferafts for lifeboats entirely, provided the liferafts on each side accommodate everyone aboard, or the total liferaft capacity reaches 150 percent with the rescue boat counting toward the total. Even under this reduced standard, the ship must still be able to accommodate everyone on either side alone if the largest craft on one side is lost.2eCFR. 46 CFR 199.261 – Survival Craft
Fishing Vessels and Small Commercial Boats
SOLAS generally does not apply to fishing vessels, so they fall under a separate U.S. regime. Commercial fishing boats must carry survival craft with enough aggregate capacity for everyone aboard, and the type of craft required depends on the boat’s size and how far offshore it operates.3eCFR. 46 CFR 28.120 – Survival Craft
Smaller boats get meaningful exemptions. Fishing vessels under 36 feet with three or fewer people on board, operating within 12 miles of the coastline, are exempt from survival craft requirements entirely. Vessels 36 feet or longer with three or fewer crew inside that same 12-mile zone can carry a buoyant apparatus instead of a full liferaft.3eCFR. 46 CFR 28.120 – Survival Craft Boats venturing further offshore or carrying larger crews face progressively stricter rules. An auxiliary craft already carried for normal fishing operations can count toward the requirement, but it cannot substitute for an inflatable liferaft.
How Each Lifeboat’s Capacity Is Set
Counting the lifeboats on a ship is not the same as knowing whether it’s compliant. Every lifeboat has a rated capacity, and no single lifeboat can be approved for more than 150 persons. The rated number equals the lesser of two figures: the number of people averaging 75 kilograms each, all wearing life jackets, who can sit in a normal position without interfering with propulsion or equipment, or the number of seating spaces meeting the dimensional standards in the regulations.4IMO Rules. General Requirements for Lifeboats – Carrying Capacity The lower figure controls, which is why a lifeboat that could physically squeeze in more people may still carry a lower certified capacity.
Compliance is measured against the number stamped on each lifeboat, summed across both sides, and compared to the required percentage for the ship’s category.
Where the Rules Come From
The Safety of Life at Sea Convention is the treaty that sets the baseline. The current version dates to 1974, with ongoing amendments.5International Maritime Organization. International Convention for the Safety of Life at Sea (SOLAS), 1974 Chapter III covers life-saving appliances and arrangements, organized by ship type.6International Maritime Organization. Summary of SOLAS Chapter III
The International Life-Saving Appliance Code, known as the LSA Code, supplies the technical detail: how survival craft must be built, tested, and equipped. Compliance with the LSA Code is mandatory under SOLAS Regulation 34.7International Maritime Organization. Life-Saving Appliances In the United States, the Coast Guard implements these standards through Title 46 of the Code of Federal Regulations, which is where the specific percentages and vessel-size thresholds cited above appear.
What Happens When a Ship Is Short
Enforcement runs mainly through port state control. When a ship enters a foreign port, inspectors from that country’s maritime authority can board and examine its safety equipment. Life-saving systems consistently rank among the leading deficiency categories producing detentions.8United States Coast Guard. Port State Control Annual Report – Deficiency Statistics Common detainable problems involve lifeboats, rescue boats, liferaft stowage, and the operational readiness of the launching appliances.
Detention means the ship cannot leave port until the deficiency is corrected. For a cargo vessel, each day in port burns money on crew wages, port fees, and missed schedules. Inspectors can also call for a drill on the spot; if the crew cannot demonstrate competent launching and recovery, that alone can justify holding the ship. Vessels that accumulate deficiencies, and ships flying flags with poor safety records, get targeted for inspection more often, so a single bad record tends to follow both the ship and its operator from port to port.