I replaced the Bow Thruster On/Off switch and thought others might want to know what part will work.
The old one was marked "APEM1, M4, 6-631H". I could not find a direct replacement from APEM.
The replacement I used is from Blue Seas "Weather Deck Panel Switch #4150, Off-On, SPST" with a Blue Seas #4138 Waterproof Boot. By the way, the waterproof boot will fit the old switches if you need replacements.
The old one was intermittently not making contact, I suspected corrosion. This would be a good inexpensive spare to have on hand, and I believe Amel used it for other devices onboard as well, for example, the Bow Thruster cut-out switch.