Suppose appropriate to first list what equipment, machinery etc. is specific to this
What comes to mind immediately :- is what engine ? the Volvo or the Yanmar?
Is the engine's service manual available ? Does the manual list any specialized tools that would be necessary to work on the engine?
What spares will be mandatory for the engine -- eg impellors, water pump etc..
Are all nuts and bolts - std Metric ? If yes, then Wrenches (Spanners) GEAR RING-OPEN END WRENCH SET -- from 6mm to 26mm ALSO a tool kit containing a full SOCKET range - something like this Tool_kit.jpg
A set of "Vice Grips" Long Nose 6LN and 9LN
Something else that comes to mind is the furling gear - guess Profurl - they may need special tools and parts and anti-seize goop.
Windlass may require very large wrench to work on.
Power tools - 12v to 18v re-chargable battery operated 1/2" Drill, Angle grinder with cutting and grinding discs.
BUY QUALITY TOOLS - even so, after use - spray with something like WD40 - keep them dry.