2026 Captain’s Edition
Cooling & Exhaust Service Record PDF
Raw Water, Heat Exchange & Exhaust Log
- 28 Pages / 134 Register Lines A4 and US Letter included.
- 924 Live Fields Interactive and 100% offline.
- 6 Calculation Models T1 through T6.
- Instant Digital Access Download links the moment you pay.
The raw water circuit and the exhaust are the two systems that fail quietly, and then all at once.
A fouled heat exchanger does not set off an alarm. It gives up a little efficiency each season until a hot afternoon at cruising revs turns into an overheat. A carbonised exhaust elbow does not announce itself either — until it takes a turbocharger with it.
Both leave a trail, though, if anyone keeps one. This is that record: a thermal baseline taken while the system is clean, sixteen trend entries against it, and the full chronology of every impeller, anode, strainer clean and exchanger service, with the engine hours beside each.
What you receive
A seven-part record for both systems, kept across seasons
- A 22-line reference page for the intervals, figures and part numbers you transcribe, with the source and page beside each
- A thermal baseline over six RPM steps — sea, raw water in and out, coolant, elbow skin, effectiveness
- 16 trend entries and 4 full sweeps, with the sea temperature on every single row
- A 10-line impeller chronology including how many vanes came back
- A 12-line anode chronology, per position, never averaged
- A 16-line exhaust inspection plus a backpressure page for what your engineer measured
A ratio, not a temperature
Every absolute temperature in a raw water circuit moves with the sea. A reading taken in February and one taken in August are not comparable, which is exactly why a published “normal” differential is close to useless: it cannot know your sea temperature, your load, your exchanger or your flow rate.
Model T2 gives you an effectiveness ratio instead — a dimensionless figure that survives a change in sea temperature between two readings. Compared against your own commissioning figure, a falling ratio is the earliest quantitative sign of scaling, fouling or a spent anode inside the core, long before a temperature alarm notices anything.
Count the vanes. Write the number down.
An impeller that comes out with five of six vanes has put one somewhere, and that somewhere is usually the heat exchanger inlet. The vanes-recovered column is the cheapest diagnostic in this document, and the one nobody keeps. Same logic on the anodes: recorded per position, never averaged, because one anode disappearing far faster than the others is a finding in itself and averaging is precisely what hides it.
On exhaust backpressure
Installing a pressure tap downstream of a turbocharger and running an engine at eighty per cent of rated load to read it is not an owner task. This record has a page for logging what a qualified engineer measured — the reading, the RPM, the method and the name. It does not tell you how to measure it, and it does not tell you to.
What it does ask you to do is find the date stamp on your exhaust hose and write it down. That is a date, not an opinion, and a hose that fails in a seaway fills a boat with water and exhaust gas at the same time.
Who it is for
- Owners who have had one overheat and do not intend to have a second
- Owners inheriting a boat with no service history and needing to start one
- Anyone planning a passage where losing the engine is not an inconvenience
- Owners preparing to sell, who want the cooling system to speak for itself
Technical specification
| Product ID | AML-MECH-2026-03 |
| Extent | 28 pages · 7 parts · 6 calculation models |
| Register lines | 134 across reference, baseline, trend, chronology and exhaust |
| Interactivity | 924 live PDF form fields — 54 tick boxes and 870 entry fields |
| Formats included | A4 and US Letter, both fillable and print-ready |
| Installations | Indirect or direct cooled marine diesel — no engine-specific data |
| Units | Unit-neutral — you set them and record which you used |
| Offline | No app, no account, no connection required once downloaded |
What it is not
This document records, structures and compares figures that you supply. It publishes no temperature range, no backpressure limit and no service interval of its own, and it reaches no conclusion about any engine or installation. It is not a service manual and not engineering advice.
Where a reading matters, the decision belongs to a qualified marine engineer working from the manufacturer's documentation for your serial number.
Instant download. Your links appear on screen the moment payment clears, and arrive by email within a minute. They do not expire.
2026 Captain's Edition · Revision 1.0 · AML-MECH-2026-03. Apex Marine Labs designs the organisational process behind good seamanship. Our documents record and organise; they do not replace a certified marine survey, a service manual, or a qualified marine engineer.