Usually these days the propeller(s) of almost every seagoing ship is particularly designed for the very ship (i.e. hull shape) and engine combination,
for the most common or typical loading situation encountered by this vessel.
This means that props are highly sophisticated and and pretty unique parts that are difficult to obtain as spare parts in any odd port en route
where a dry-dock may be available for the change of props.
I think this is even more true for those highly loaded ducted propellers of AHTS and the like.
Of course, if there isn't a 100% matching prop for the ship some nearly fitting stock propeller
(i.e. with similar particulars such as diameter, (mean) pitch to diameter ratio P/D, ratio of expanded area to disk area Ae/Ao, blade number etc.; see
ITTC Wiki for definitions),
will do as well, but this isn't quite optimal.
For that reason it is safer to carry ones own spare props if one can afford.
If the props are controlable pitch propellers (CPP) then it usually suffices to carry some spare prop blades.
On the other hand, with fixed pitch propellers (FPP), such as in AZIZ's case, one has to carry the whole spare screw.
For mounting the spare prop of course docking will be required.
Marine propellers might fail more often than their rigid appearance may suggest at first sight.
For once, because of the higher density of the medium they operate in, they are more heavily loaded than for instance air screws of aeroplanes.
Then the detrimental effect of cavitation, which often in some load cases cannot be avoided, can severely erode propeller blades up to total loss of blades.
Another peril are vibrations due to a bad (or rather incorrectly predicted) wake field in the propeller plane.
For vessels that are operating in icy waters, like icebreakers, of course particles of cut or crushed ice may damage the propellers.
Or any other parts or debris that happen to hit the props.
In that respect I'm not sure whether the standard procedure of anchor towing from the sea bed,
especially when hoisting vertically, doesn't bear the risk of the tow line or even anchor to accidentally hit the props.