A battery can deliver thousands of amps into a short. The cable from the battery to the first fuse is the only part of the circuit with nothing to stop that, which is why ABYC E-11 keeps it short. An unfused house bank cable chafing on an engine bearer is how boat fires start.
What the standard asks
ABYC E-11 asks for overcurrent protection on every ungrounded conductor within 7 inches of the point where it connects to the power source, measured along the wire. In our words, the exceptions: up to 72 inches when the conductor connects directly to the battery and runs in a sheath or enclosure such as conduit for its whole length, and up to 40 inches in some other cases with the same sheathing. Engine cranking circuits have an exception. MarineHowTo's author, who sits on the E-11 sub-committee, advises fusing them anyway. ISO standards used under the RCD set a similar distance of 200 mm.
How a surveyor checks it
Follow each positive cable from the battery post to its first fuse or breaker and measure. Then look at the fuse. It has to be sized for the cable, and able to interrupt the current the bank can deliver. MarineHowTo gives ABYC's planning figures as about 3,000 A of short-circuit current per 100 Ah for flooded batteries and 5,000 A per 100 Ah for AGM and lithium, and lists interrupting ratings of about 6,000 A for an ANL fuse, 10,000 A for an MRBF and 20,000 A for a Class T. A big lithium bank behind an ANL fuse can outrun it.
Check the cable too. Chafe, heat, loose lugs and cables resting on the engine turn a missing fuse into an A.