Early warning systems                            8- ‘24
I do not think about alarms and early warning systems too often: they just exist and are largely ignored, until... Every now and again one really makes a difference in my cruising life: so I cobbled together this list: I am sure I missed a few.
My best, Dick Stevenson
I would suggest that there should be a handful of early warning systems that a skipper should install. This goes especially for recreational skippers and even more so for those who sail as a passage-making couple. The benefits of an early warning do not always jump out at you. Many of the following early warning systems are warnings where vessel integrity and crew safety are at risk. Early warning puts skipper and crew in a pro-active position rather than reacting to, say, the floorboards being awash where it is likely already too late to enact a remedy. Some early warnings are crucial (propane leak) while others are a flag to attend to something later (slow leak of coolant). But every early warning allows for remedies and intervention when the intervention can still make a difference.
A few minutes of early warning can be the difference between saving the ship or abandoning her. It allows a period of thinking rather than a quick journey into panic. Many emergencies on board escalate quickly: easily dealt with at the onset they can quickly become unworkable: early intervention makes a huge difference.
Early warning systems on Alchemy:
1.    *Smoke detectors (combined unit with CO detectors): engine room, above electrical panel and in the forepeak cabin.
2.    *High water alarms: Alchemy has two, one in each of her isolated bilge areas.
3.    *Propane sniffers: Alchemy has two, one in each of her isolated bilge areas.
4.    *Bilge pump alarm: every activation of the bilge pump
5.    Raw water failure alarm (Borel) on engine and genset
6.    Dedicated CO detector (required, I believe)
7.    I have a very quiet ship, but I have never completely tamed the lines that raise and lower my pole on the mast: at 20-25 knots of wind from the bow at anchor, they slap the mast. This is my wake-up call to check things out.
Requiring inspection:
1.    There is a dam down stream from the engine and genset where any leaked fluids accumulate: a quick opening of the over the engine access hatch allows a look.
2.    My dual Racor filter assembly has a vacuum gauge which can give early warning of filters becoming loaded and blocking/slowing fuel delivery and other forms of fuel constriction.
Do not have (or use) but may be wise:
1.    A low and high voltage alarm (or SOC/state of charge alarm)
2.    Various instrument alarms: AIS, Radar, depth, etc.
3.    Anchor alarm
*In my opinion, these should be required to be installed by the manufacturer when installation is far easier. I would suggest every boat should consider installing these alarms.