The short version
- Two rules require a hospital space: 46 CFR 92.20-35 for cargo and miscellaneous vessels and 46 CFR 108.209 for MODUs.
- Both trigger at twelve or more on a voyage of more than three days. The cargo rule counts crew, the MODU rule counts persons.
- One berth per twelve persons or portion thereof, excluding anyone berthed in a single occupancy room, capped at six.
- 46 CFR 108.210 and 92.20-35(e) remove the requirement where a designated treatment or isolation room is available for immediate medical use.
- Small passenger, towing and fishing vessels have no hospital space rule at all. They have kit rules instead.
The governing rule ranks ninth, behind a Geneva Convention
A live capture of the first page for this question in August 2026 is worth describing in full, because it is the clearest example yet of a page Google cannot fill properly.
Position one was an EU medical chest supplier. Then an Indian maritime site, a crewing company, the Wikipedia article on hospital ships, a document sharing site, the US Navy shipboard medical manual, a forum thread, and the International Committee of the Red Cross treaty database entry for the Geneva Convention on Wounded and Sick members of armed forces at sea. The actual United States regulation appeared last, in ninth place.
Two of the nine results are about entirely different subjects: naval hospital ships and the law of armed conflict. That is a page being padded because nothing operator facing exists to fill it. The generated summary did name the right section, which is more than it managed for several other queries, but it stopped at the headline trigger and omitted both the berth formula and the exception that removes the requirement altogether.
One threshold, two subchapters
Two United States rules require a hospital space, and they share a trigger word for word: twelve or more persons, on a voyage of more than three days.
| Rule | Applies to | Trigger |
|---|---|---|
| 46 CFR 92.20-35 Subchapter I |
Cargo and miscellaneous vessels[1] | Voyages exceeding three days between ports, with crews of twelve or more[1] |
| 46 CFR 108.209 Subchapter I-A |
Mobile offshore drilling units[2] | Carrying twelve or more persons on a voyage of more than three days[2] |
Note the difference in wording that matters. The cargo rule counts crew. The MODU rule counts persons, which on a drilling unit sweeps in the entire industrial complement rather than the marine crew alone. On a unit with fifteen marine crew and eighty drilling personnel, that distinction is the whole question.
Note also which classes are absent. Small passenger vessels, towing vessels and commercial fishing vessels have no hospital space rule at all. They have kit rules instead[5][6][7], compared in the vessel class comparison, so a vessel can owe a compartment and no specified contents, or contents and no compartment, purely by subchapter.
What the rule actually specifies
The MODU version is the more detailed of the two and runs to ten lettered paragraphs. It is worth reading closely because almost none of it is guessable.
| Requirement | 46 CFR 108.209 | Why it is missed |
|---|---|---|
| Separation and use | Suitably separated from other spaces, and no hospital space may be used for any other purpose when used for care of the sick[2] | The qualifier “when used for care of the sick” is narrower than a blanket prohibition, and operators read it both ways |
| Access | An entrance wide enough and arranged to readily admit a person on a stretcher[2] | A door that meets the accommodation standard can still fail this. It is a geometry question, not a width question |
| Berths | Made of metal. Upper berths hinged so they can be secured clear of the lower. At least one berth accessible from both sides[2] | Three separate structural requirements in three consecutive paragraphs, none of them obvious |
| Number of berths | One for every twelve persons or portion thereof who are not berthed in single occupancy rooms, capped at six[2] | The single occupancy exclusion cuts the number sharply on modern units, and it is routinely applied to the wrong headcount |
| Sanitary and fittings | Toilet, washbasin, and bathtub or shower accessible from the space. Clothes lockers, a table and seats[2] | “Accessible from the hospital space” is stricter than “nearby” |
The cargo vessel version at 92.20-35 covers the same ground more briefly: situated with due regard to the comfort of the sick so they receive proper attention in all weathers, suitably separated, used for the care of the sick and no other purpose, the same one in twelve berth ratio capped at six, and a toilet, washbasin and bathtub or shower conveniently situated with other suitable equipment such as a clothes locker, a table and a seat[1].
The exception that removes the requirement
Both rules contain a way out, and it is the single most valuable paragraph on this subject because it converts a construction problem into a designation problem.
46 CFR 108.210, Hospital space not required
The hospital space is not required if one single or double occupancy sleeping space, designated and equipped as a treatment or isolation room or both, is available for immediate medical use, and has an entrance wide enough and arranged to readily admit a person on a stretcher, a single berth or examination table accessible from both sides, and a washbasin in or immediately adjacent to it[3].
46 CFR 92.20-35(e) does the equivalent for cargo vessels whose crew are berthed in single occupancy rooms, requiring one room designated and fitted as a treatment or isolation room, available for immediate medical use, with a washbasin with hot and cold running water in or immediately adjacent and other required sanitary facilities conveniently located[1].
Three words carry the weight. Designated means somebody has written down which room it is. Equipped means it is fitted for the purpose rather than merely empty. Available for immediate medical use means it cannot be somebody’s occupied cabin at the moment it is needed. An operator relying on this exception without a designation on paper is relying on nothing.
What the hospital rule does not do
Three assumptions follow the words “hospital space” onto a vessel and none of them survives the text.
- It does not require a doctor, a nurse or any medical care provider. Neither section names a role. It is a compartment standard, and who provides clinical judgement is a separate decision, framed in the evacuation article.
- It does not specify medical contents. Toilet, washbasin, bath or shower, lockers, table, seats. Nothing clinical. The contents question is answered by your class kit rule and by the chest logic in how to stock a chest and requirements by flag state.
- It does not change your reporting duties. Casualty notice under 46 CFR part 4[10] and logbook entries under 46 USC 11301[9] apply whether or not a hospital space exists. The threshold that triggers them is in the beyond first aid article, the records position in crew medical records, and the worst case sequence in the death on board procedure.
What to write down
- Do the headcount the way the section does it. Persons on a MODU, crew on a cargo vessel, and exclude single occupancy berthing from the berth formula rather than from the trigger.
- Decide which route you are on and record it. A built hospital space, or the designated treatment room exception. Most modern units qualify for the exception and have never claimed it in writing.
- Check the three geometry items physically. Stretcher entrance, a berth accessible from both sides, washbasin in or immediately adjacent. These are the ones that fail on a real vessel.
- Write what the space is stocked with, since the rule does not. That list is where your class kit rule and your chest reasoning meet, covered across the towing rules, the Subchapter T article and the Subchapter L article.
- Keep the designation current. A treatment room that has quietly become permanent accommodation fails the immediate use test the day it matters, and the audit view of that is a compliance audit.
If you want the compartment assessed against the section and the exception claimed properly in writing, that is maritime medical consulting, with the contents side in chest management. The library index is the guidance library and the reviewing physician is on the about page.
Common questions
When does a US vessel need a hospital space?
When it carries twelve or more persons on a voyage of more than three days. That is the trigger in 46 CFR 92.20-35 for cargo and miscellaneous vessels and in 46 CFR 108.209 for mobile offshore drilling units. Below that threshold neither section applies, and no kit rule fills the gap. The kit rules by class are compared in the vessel class comparison.
How many berths does the hospital need?
One berth for every twelve persons or portion thereof who are not berthed in single occupancy rooms, and the number need not exceed six. Both sections use the same formula. Note the exclusion: people in single occupancy rooms do not count toward the berth calculation, which is why modern accommodation often reduces the requirement sharply.
Can we avoid building a hospital space?
Often, yes, and this is the provision most operators have never read. 46 CFR 108.210 removes the requirement on a MODU if one single or double occupancy sleeping space is designated and equipped as a treatment or isolation room, available for immediate medical use, with a stretcher width entrance, a berth or examination table accessible from both sides, and a washbasin in or immediately adjacent. 46 CFR 92.20-35(e) does the same for cargo vessels with single occupancy berthing.
Does the rule say what equipment goes in the hospital?
Almost nothing clinical. It specifies a toilet, washbasin and bathtub or shower, clothes lockers, a table and seats. It says nothing about medicines, instruments or monitoring. The medical contents question is answered by the kit rule for your class, and by the chest regimes described in requirements by flag state and how to stock a chest.
Do the berths really have to be metal?
On a MODU, yes. 108.209(e) requires each berth in a hospital space to be made of metal, (f) requires each upper berth to be hinged so it can be secured clear of the lower berth, and (g) requires at least one berth accessible from both sides. These are structural details an operator will not guess and a surveyor will check.
Does having a hospital space mean we need a doctor?
No. Neither section requires a physician, a nurse or any designated medical care provider. It is a compartment standard, not a staffing standard. Who provides clinical judgement is a decision the operator makes separately, and the framework for it is in the evacuation article and the six decisions.
What about small passenger, towing and fishing vessels?
None of them has a hospital space rule. They have kit rules instead, at 184.710, 140.435 and 28.210 respectively, and those are compared in the vessel class comparison. A vessel can therefore be required to carry a first aid kit and not a hospital, or a hospital and no specified kit, depending entirely on which subchapter it sits under.
