Tips & Tricks
Impeller - How to tell and what to do if your impeller needs replacement on Charter
The what? Exactly.
Impellers are a commonly replaced item on any charter yacht with an engine. An impeller is a small rubber wheel that spins as a part of the engines cooling system. It sucks water into the engine to help keep it cool. Over time, the "fins" on the impeller wheel wear down or break off. When this happens less water is pumped though the engine, thus the engine will heat up. When they fail outright, the engine can overheat. When chartering, failure is rare. Charter Companies follow a strict schedule, changing impellers about every three months.
It's helpful to know how to tell your engines are cooling the way they should be. After all, not many charter sailing yachts have a full suite of engine gauges.
If you see little water coming though the exhaust and / or the exhaust is whitish your engine may be running warm. Onboard a Catamaran, you can compare to see if the exhaust output is different from one side to the next. If one side has a steady flow of water and a clear exhaust and the other has a trickle and whitish smoke, the impeller probably should be looked at or replaced.
Raw Water Filter
Think of a pool filter. They have a basket sitting inside a bucket of sorts. On a yacht, it's basically the same thing. On top of the engine is a clear cup, with a basket strainer. Just like in a pool. You can see the water though the clear cup running though the filter. If you don't see a good flow of water, you've got a worn impeller. Again, with a Catamaran, you can visually compare the flow though the filter from one engine to the other.
The good thing about impellers is that they give you signals way before they stop doing their job and they are simple things to replace. Because maintenance schedules keep charter yachts in fresh impellers on a regular basis, we've seen one worn impeller in over a decade of sailing the BVI's and zero failures. Impellers don't actually fail, when they wear, they slowing become less and less effective. Even if you were to see the signs we mention here while out on charter, there is still water moving though the engine, and the impeller is turning. Just not as effectively as it should be. But that one time ours showed signs of wear, we we're glad to know what signs to look for. The few extra minuets we took to pop in a new one was the right thing to do. Even if all we were doing was saving wear on the engine. We look at it this way. If she were ours what would we do? We'd pop in a new impeller.
If you think you have a worn impeller on charter, what should you do?
Head for the nearest safe harbor. A mooring field preferably. If you can sail, do. You're on a sailboat. You don't actually need the engine until mooring time.
On a Cat, you can run on one engine if sailing really isn't an option. Sailing is always preferred over running one out of two engines. It's also important to remember, one engine equals hand steering. Do not use Otto (auto helm). It will get over worked and break.
Call the charter company. Let them know what you noticed and where you're headed. They will have a mechanic meet you with a fresh impeller.
When we called in, it took 30 min to an hour, and we were back underway.
"A captain knows his vessel is ship shape, not though finding what's wrong, but by knowing what's wrong and not finding it."- Capt. KJ
- Charter Review: The Moorings 5800 Ocean Suite by Captain Kev
- Charter Review: VOYAGE Charters, VOYAGE 520 Silver Lining by Capt. Kev