The most common and most likely answer to this crossword clue is the 9 letter word TARPAULIN
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More clues leading to the result TARPAULIN
- Man one observed entering small lake in waterproof
- Apostle boarding moving train has protective covering
- Sailor finds girl endlessly old hat
- Jack, boy in weatherproof material
- Sailor, with ache around middle of hull, gets shipboard cover
- Cover fool returned, saying it’s completely knackered
- Missionary pursues sailor wearing his hat
- Sailor detailed woman to find cover
- Jack and I wearing heavy-duty cloth
- Thanks to brief adjudication, father enters canvas
Buddy explains!

The straight part
We know that "shipboard cover" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case shipboard cover = tarpaulin.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does TARPAULIN mean?
TARPAULIN noun- A tarp, a heavy, waterproof sheet of material, often cloth, used as a cover or blanket.
- A sailor (often abbreviated to tar)
- Any heavy, waterproof material used as a cover.
- Canvas waterproofed with tar, used as a cover.
- A hat made of, or covered with, painted or tarred cloth, worn by sailors and others.