I assume you are looking at image intesification (II) binoculars or similar, rather than the $10,000 infra red (FLIR) systems which are in another league entirely. I used commercial
II binoculars on rescue
craft with good results. They are quite useful in 'starlight' conditions, but nowhere near as sensitive as the military spec versions.
Not particularly expensive, but not top of my list of priorities. You will find plenty of sources online.
Used with torch or search lights, you can see objects quite clearly that you cannot see using low-spec II alone. For instance, I navigated the lifeboat through a field of lobster pot buoys picking up the light thrown out by nav lights. I could pick the buoys up at 100-200 metres.
Some things to consider include:
 Need to protect night vision, e.g. only one person to use them at a time. Best not the helmsperson or skipper
 Look for the highest spec version you can. Commercially available 'Western' products are typically labelled Gen 1, Gen 1+ (sometimes Gen 2?). This is the 'Generation' of device; get later generations for MUCH better low light performance.
 Poor depth
perception & restricted field of view. You often need to confirm distance by secondary means (OK - just good practice). Easy to look at something or check sector for hazards; harder to maintain 360 deg situational awareness.
 People get seasick just looking through them!