Carry A Spare Alternator??
- Thread starter GeneraiT001
- Start date
In a perfect world.....Yes, UPS doesn't deliver to the middle of the ocean.
I imagine a used one is the way to go with this?
Depends on the alternator. If you are keeping the stock OEM alternator, I'd buy a new one, they are not that expensive. If you go with a high amp externally regulated alternator, then a rebuild kit (and the tools you need to rebuild it) and the original alternator would be a choice.
Thanks.
Think I'd like to keep it simple and "cheap" so I'll look for the stock OEM...which I guess has a built in regulator (80A)? Yanmar 4JHE
When I switched down to a 75A alternator from the 125A that came with the boat, I bought two new alternators. Up to you in terms of risk and cost.
The original alternator for many Yanmars was a Hitachi 80. I don't believe they are made anymore.
Here's an article you might find useful.
Automotive Alternators vs. Deep Cycle Batteries - Marine How To
A Deep Cycle Battery Assassin The alternator pictured here helped to destroy a very expensive bank of TPPL AGM batteries in under two years. These batteries need an absorption voltage of 14.7V. The highest voltage I recorded on this vessel was 13.58V at the battery terminals. At this
marinehowto.com
Can you/do you need to change the alternator while at sea? If it ain't going to happen, then don't bother with a spare. The ruthless question to ask yourself about any spare parts before you devote space and carrying costs to something you are not going to use. Far better to sink your money into making your existing alternator installation as bullet-proof as practical.
just my opinion
Fred W
just my opinion
Fred W
Things happen and it would be somewhat comforting to know its there. What are the odds you'll need to use your lift raft??....probably less than the odds of changing out an alternator....but would you go to sea without a lift raft??
As I said, the question to answer is, "are you willing/able to change out the alternator at sea?" If the answer is no, there is no point in taking the alternator. If the answer is yes, then taking a spare is up to the owner.
An alternator failure in and of itself, does not render the boat incapable. It will drag down the electrical system over time. A working electrical system is more critical to some sailors than other sailors. A sailboat can still be sailed.
OTOH, loss of the hull does render the boat incapable, and a life raft is the best alternative. I don't carry a life raft as it takes too much space/money, and time and effort to deploy, based on the risks it addresses. I do wear a pressure activated life vest with a PLB when sailing single handed because it addresses a wider range of risks than a life raft - ie., falling overboard.
A risk analysis that considers real probabilities and real consequences is usually worth conducting. Results will differ from one sailor to the next, and from one boat to the next. But all too often, it's the failures that were unplanned for that make for the most interesting reading from survivor(s).
Fred W
An alternator failure in and of itself, does not render the boat incapable. It will drag down the electrical system over time. A working electrical system is more critical to some sailors than other sailors. A sailboat can still be sailed.
OTOH, loss of the hull does render the boat incapable, and a life raft is the best alternative. I don't carry a life raft as it takes too much space/money, and time and effort to deploy, based on the risks it addresses. I do wear a pressure activated life vest with a PLB when sailing single handed because it addresses a wider range of risks than a life raft - ie., falling overboard.
A risk analysis that considers real probabilities and real consequences is usually worth conducting. Results will differ from one sailor to the next, and from one boat to the next. But all too often, it's the failures that were unplanned for that make for the most interesting reading from survivor(s).
Fred W
Of all the things that might fail on a boat at sea, the alternator is probably one of the easiest to swap out. A couple of bolts, a couple of wires, and it is done.
Along with the alternator carry a couple of belts.
Along with the alternator carry a couple of belts.
In the worst case it could also seize and render the engine unusable. Maybe not high probability risk but could be worth accounting for, especially if offshore.
While I've never had an alternator fail in terms of no longer charging, I have had one seize rendering the engine unusable. I carried one of those adjustable link belts so that I can quickly bypass the alternator and keep the water pump running (they are on the same belt).
Mark
I have had an alternator fail due to a ham handed mechanic who broke the temp sensor. Fortunately, I had a spare alternator, unfortunately it was sitting in my basement 1500 miles away. 
In a perfect world, buy a new one and install it, then keep your (known good) used one as spare.
You’ll also want every type of water pump on your boat, every type of fuse or breaker, a spare Morse cable (longest on your boat) and the list goes on. Lubes, filters, tools, longest line in your running rigging…. It is a very long list….
my solution too - when I installed a high output Balmar on Escape I cleaned and carried the stock alternator on board. An easy emergency re-install, and even if the diesel doesn't require electricity to run, a lot of your equipment - nav, radios, refrigeration does
There is some sort of algorythmic equation to the question. One would need to measure cost and space against likely need and availability.
Not sure I'd buy an additional alternator to carry around. An old working one as a spare yeah, probably. Bearings and diode would probably be a good idea. Even if you are not capable of doing that fix there'd likely be someone around who could but would need the parts.
Same thing for all the water pumps. Particularly the one for the AC, though not especially an issue where you are now.
Not sure I'd buy an additional alternator to carry around. An old working one as a spare yeah, probably. Bearings and diode would probably be a good idea. Even if you are not capable of doing that fix there'd likely be someone around who could but would need the parts.
Same thing for all the water pumps. Particularly the one for the AC, though not especially an issue where you are now.
On the topic of alternators, John Harries on Affordable Adventure Cruising has recently published a couple of articles on alternators.
If you are not familiar with John or his website, he is a well respected cruiser who has extensive history in the sailing business. He and his wife have spent considerable time sailing in the high latitudes in Canada and Greenland. His articles are always informative and informed. His following includes many industry professionals, fellow cruisers, and notable experts. It is behind a paywall, however, his subscription fee is very modest for the amount of information that can be garnered from his site, especially if one is planning an extended cruise.
If you are not familiar with John or his website, he is a well respected cruiser who has extensive history in the sailing business. He and his wife have spent considerable time sailing in the high latitudes in Canada and Greenland. His articles are always informative and informed. His following includes many industry professionals, fellow cruisers, and notable experts. It is behind a paywall, however, his subscription fee is very modest for the amount of information that can be garnered from his site, especially if one is planning an extended cruise.