Finding and choosing a mechanic
Which trade does which job, mobile versus workshop versus haul-out, and what to ask before booking.
What should I do first when the engine stops?
Assess safety, anchor if you can to stop your drift, and tell someone your position. Diagnose after that, not before.
Full guide: Emergency and On-Water Breakdown Repair
Can I keep motoring with an overheat alarm?
No. A marine diesel with no cooling water damages itself in minutes, and an overheating exhaust hose is a fire and flooding risk.
What is the most useful repair to learn?
Changing the impeller and changing and bleeding fuel filters. Between them they cover a large share of on-water breakdowns.
Is it cheaper to be towed or repaired on the water?
Often towed. On-water attendance carries a premium and conditions limit what can be done. Recovery is cheaper than damage from running a failing engine.
My engine stopped and won't turn over — what now?
Do not force it. It may be hydrolocked, and cranking bends rods. Get it assessed.
My alarm sounds intermittently for no reason — can I disconnect it?
No. Fix the fault. An alarm you have learned to ignore leaves you unprotected when the real one sounds.
Full guide: Engine Alarms and Instrumentation
How do I know my alarms work?
They should sound at key-on before starting. If they do not, the circuit is faulty and you have no warning system.
What is the most useful alarm to add?
An exhaust temperature alarm. It detects loss of raw water flow before the engine coolant temperature rises, which is meaningfully earlier warning.
My gauge reads high but the engine seems fine — which do I believe?
Treat it as real until proven otherwise, then have the sender and connections tested. Senders fail often, but assuming that is the answer is how engines get destroyed.
I just bought a boat — what should I check?
That the alarms have not been disabled. It is more common than owners expect.
Is a marine mechanic different from a diesel mechanic?
On the injection side they overlap. On cooling, exhaust, corrosion, gearboxes and drives, marine is a separate trade with no automotive equivalent.
Full guide: Marine Diesel Mechanic
Do they come to the boat?
Usually. Most marine engine work happens at the berth or on a mooring; bench and haul-out work are the exceptions.
Why is marine servicing more preventive than automotive?
Because a breakdown at sea is a different category of problem. Replacing an impeller on schedule instead of on failure is proportionate, not excessive.
Can a truck mechanic work on my boat engine?
For injectors and pumps, sometimes. For everything marine-specific, no.
How do I check they know my engine?
Ask how many they see. Marine engines vary far more than car engines, and familiarity is the difference between an hour's diagnosis and a day's.
My engine cranks slowly — is the starter failing?
Possibly, but check the batteries, cables and earths first. Corroded connections and tired batteries produce identical symptoms far more often.
Full guide: Marine Engine Electrical and Charging
Can I fit an automotive alternator to save money?
Don't. Marine units are built for the vibration, salt and duty, and in petrol installations there is an ignition safety requirement as well.
My batteries read fine but won't crank — why?
Resting voltage tells you little. A battery can read 12.6V and collapse under cranking load. Load testing is the test that matters.
Why do my instruments read strangely?
Frequently a corroded earth or a failed sender rather than an engine fault. Check before acting on the reading.
Is a mobile marine mechanic more expensive?
Attendance is charged, but for most marine work there is no alternative — the boat cannot come to them. Berth attendance is cheaper than mooring attendance.
Full guide: Mobile Marine Mechanic
Will they come out to a swing mooring?
Many will, with a tender, and it costs more. Some will not. Ask when booking, and say up front that the boat is on a mooring.
Can they do a full service at the berth?
Yes. Servicing, cooling work, fuel system, electrical and most repairs happen dockside as standard.
Does my marina need to approve them?
Frequently yes. Many marinas require contractors to be registered and insured with them before working on site.
What if they can't fix it at the boat?
Ask before booking. Most charge attendance and diagnostic time and can arrange or recommend the workshop or haul-out required.
What engine work needs a haul-out?
Anything below the waterline — shaft, cutless bearing, propeller, most stern gland work, sterndrive removal, saildrive seals, hull anodes and skin fittings.
Full guide: Slipway and Haul-Out Engine Work
Can I use my own mechanic in the yard?
Often, but many yards restrict contractors or require them to be registered and insured with the yard. Confirm before booking.
Should I combine engine work with antifouling?
Yes. The lift is a fixed cost, so scheduling everything at once is materially cheaper than separate haul-outs.
Why does alignment happen after relaunch?
Because the hull changes shape between the hard stand and the water. Alignment set on the hard drifts once the boat is floating.
How far ahead should I book?
In busy markets, well ahead — yard availability generally sets the date rather than the mechanic's.