steering hydraulic, where to top up

[About Time]

The black reservoir behind the electronic box is for sure for the power steering.
I do not see in your engine bay the reservoir for the trim. Here is a link that shows how the trim reservoir looks:
https://www.marinepartseurope.com/da/volvo-penta-spraengskitse-7744470-44-7623.aspx
Part # 3861570.

 

[simonfraser]

Perfect, found it too.
Reservoir hiding behind the battery, that will need removal for topping up with standard hydraulic fluid ?
Easily touch the top of the fluid with my finger, no dip stick.
Interesting it does not look low on fluid as there is a minor weep on one of the trim rams.

 

[About Time]

Yes standard ATF fluid. Usually it does not require top up. Maybe a change every 10 year.