Repower a sailboat is a decision complicated and with many variables.
When should we consider repowering? Where is the correct line between repair a marine engine or replace it? There is not a unique answer, there are as many as ships and shipbuilders. But it is always possible to analyze the situation to try to find the best answers.
If the boat engine is old, has many hours on the tachometer, has difficulties to start, it is too smoky at the exhaust, it overheats, leaks oil, does not reach its power, the cooling water gets mixed with oil or there is no way to find spare or replacement parts, the solution is repowering. This will solve everything at once.
This long failure list don’t usually occur suddenly or simultaneously. While the engine ‘works’ the best decision seems to repair. But when the engine fails is the time to take more drastic decision.
Installing a new engine has many advantages: You update the technology, new blocks are lighter, smaller and quieter, it has less exhaust emissions and fuel consumption is also reduced.
The new marine engines also come with factory warranty and should not be any problems in the supply of spare parts. Installing a new engine to our boat makes you forget the uncertainties of whether the engine will start in the morning or if it will suddenly stop at the farthest point of our summer cruise.
What is the life expectancy of an engine?
A properly maintained diesel engine can achieve a life of about 20,000 hours. There are many generators or commercial fishing boats that reach it in good shape. But this is something you rarely get at pleasure boats.
The ‘life expectancy’ of an engine of a sailboat or motor boat is between 5,000 and 10,000 hours. Before the 5 thousand, repairing seems the best option. From there, a major repair is an investment with little profit.
The main reason why marine engines of professional boats last 4 times longer (in time, not in working hours) than leisure boats is as simple as time…
The main engine of a commercial fishing boat is usually working around 2,000 hours per year (charter are the exception) as pleasure boats are on average about 100 hours of engine per season. When a yacht has worked for 2,000 hours, often has reached his twenties, an age that in terms of oxidation and internal corrosion is more important than the hours of the tachometer. So when a commercial fishing boat reaches 20,000 hours of engine operation, its mechanical is just 10 years old, an age at all exaggerated in their lifespan.
Repairing vs repowering
The decision starts with an economical reason. The item to analyze is not the total amount, but the profitability over time.
At a certain age, the profitability of marine engine reparation is debatable. Spare parts are usually expensive and difficult to find. And if you rebuild an engine, you need to do the same with the transmission. Otherwise all the structure might end up damage. And even repaired, the engine is still old.
It is also common that during the repairing process, many pieces break due oxidation or internal corrosion, which is difficult to notice from the outside. The internal circuits of the XX might have been corroded by the water conductions… Which will thin the metal walls.
We must also consider who will be re-building the marine engine. There is a big economical difference in between doing it oneself or relying on an specialized workshop, and also on the final result. You need a specific knowledge and special tools to achieve a successful repair.
There are many variables to consider and my recommendation, if hesitating, is repowering your boat. This is the decision I took in my ship.
This post is also available in: Spanish