Essential Shipyard UniversityService Tech 1 · Introductory
The real starter jobs, taught the way ESI does them — every lesson is an actual job on an actual boat, with the standards, safety, and ecology flagged right where they matter. This is where a new tech becomes useful on the dock and on the hard.
Course roadmap
Each is a real job. Standards, safety, and ecology are flagged inside the job — never a separate lecture.
The full ten-lesson course. Each is a real job — work top to bottom, and pass each lesson quiz at 80% as you go.
Lesson 1 · Your kit
A premium tool roll in a saltwater yard is money in the bilge. We carry good, replaceable tools — and we know which ones snap fasteners and break knuckles.
Your starting kit is a mechanic's socket set plus a ratcheting wrench set, in both metric and SAE (standard) — you'll see both on marine hardware, and guessing wastes the fastener. The socket set spans all three common drives, and you use them for different work:
| Drive | What it's for |
|---|---|
| 1/4" | Small, tight, low-torque fasteners — clamps, brackets, electrical, panel work. |
| 3/8" | The everyday workhorse — most engine and system fasteners live here. |
| 1/2" | Big fasteners and breaker-bar work — couplings, motor mounts, steering, anything seized. |
You also carry torque wrenches — at minimum a 3/8" drive and a 1/2" drive. Not one, both: the 3/8" covers the everyday range where most engine and system fasteners live, and the 1/2" covers the big stuff — couplings, mounts, steering, drive hardware. A single wrench cannot cover that spread accurately, because a torque wrench is only trustworthy in the middle of its range. Section 5 covers how to use them and how not to ruin them.
Target a set in the ~300-piece range so you're not missing a size mid-job, add ratcheting wrenches and Allen/hex keys in metric and SAE, and carry screwdrivers with interchangeable bits rather than a bag of loose drivers.
Round the kit out with the striking and test tools you'll reach for constantly. For persuasion: a ball-peen hammer, a 2 lb small sledge for when a job genuinely needs force, and a dead-blow for driving parts home without marring the surface or bouncing back. For diagnosis: a multimeter with a built-in non-contact voltage (NCV) tester — the NCV gives you a fast live/dead check before you ever put a hand or a tool near a wire, and the meter is your first move on any electrical or charging complaint.
And the cart always carries the cleaning kit — a spray bottle of Simple Green and clean rags. That isn't an afterthought at ESI; it's how you use every spare minute (see the downtime standard in Lesson 2).
A missing socket is a stopped job, so ESI runs a simple, strict accountability standard:
Salt is the enemy of both grip and accuracy. A corroded six-point rounds off inside instead of gripping, and a rusty socket slips and rounds the fastener — turning a two-minute job into a stuck-fastener job. So the care standard is simple: wipe down and lightly oil after any saltwater exposure, dry before storing, and never leave tools sitting in a wet bilge. A rusty socket isn't repaired — it's retired and replaced (see accountability), which is exactly why we don't cry over cheap tools.
Two tools break fasteners loose, and both can hurt you or the boat if you reach for the wrong one. Knowing when to use which is what separates a tech from someone who snaps bolts.
The impact wrench delivers fast hammering torque — great for spinning off a non-critical fastener you already know is healthy. But that same hammering is exactly how it snaps things: on a corroded, seized, or undersized bolt it will shear the head clean off before you feel any resistance, and on a soft fastener it rounds the flats. You get no feedback — the fastener can't "talk" to you through an impact.
The breaker bar is a long, non-ratcheting handle that multiplies your force to crack a stubborn fastener loose by hand — with feel, which is why it beats an impact on anything corroded. But that leverage is stored energy: when the fastener either breaks free or the bolt snaps, all that force releases instantly and your body follows the bar. That is how techs put knuckles into an engine block or fall into machinery.
When a fastener won't come with a proper breaker bar and good technique, you don't reach for a bigger bar or an impact — you're now in the stuck-fastener protocol (penetrant, heat/induction, and knowing when to call fabrication). That's Lesson 7, and forcing it here is how boats and hands get broken.
A breaker bar is a lever. A torque wrench is a measuring instrument that happens to be shaped like one. Treat it as a tool and you will quietly destroy its accuracy, and it will keep clicking confidently at the wrong number while you go on trusting it.
| Drive | Where it earns its place |
|---|---|
| 3/8" | The everyday range — most engine and system fasteners. Where you'll spend the majority of your torque work. |
| 1/2" | The big end — couplings, motor mounts, steering hardware, drive fasteners. |
Both, not one. A torque wrench is least accurate at the very bottom and very top of its range, so one wrench stretched across the whole spread is wrong at both ends.
Every torque figure you will ever be given is in one of three units. Read the unit before the number, because the same digits mean wildly different things.
| Unit | Written | What it's used for |
|---|---|---|
| Foot-pounds | ft-lb, lb-ft, ft/lbs | Big fasteners. Motor mounts, couplings, steering hardware, drive bolts, prop nuts. Arm force on a long wrench. |
| Inch-pounds | in-lb, lb-in, in/lbs | Small fasteners — screws. Clamps, covers, sensors, cable anchors, pump housings. Wrist force on a short wrench. |
| Newton-metres | N·m, Nm | The metric unit. European engines — Volvo, Yanmar — often lead with Nm, and most manuals print both. |
The conversions:
Some worked examples so the scale is concrete:
| Fastener | Spec | Same value, other units | Feel |
|---|---|---|---|
| Shift cable core wire anchor screw | 20 in-lb | 1.7 ft-lb · 2.3 Nm | Fingers and wrist. A screw. |
| Water pump body screws | 60 in-lb | 5 ft-lb · 6.8 Nm | Still wrist. Small hardware into aluminum. |
| Drive-to-bell-housing nuts | 50 ft-lb | 600 in-lb · 68 Nm | Firm arm pull on a proper wrench. |
| Bearing carrier retainer nut | 210 ft-lb | 285 Nm | Serious. Both hands, braced. |
Values shown are MerCruiser Alpha One Gen II figures, used here only to show the scale of each unit. Never carry a number from this table to a job — every fastener's spec comes from the manual for the machine in front of you.
Using it properly:
ESI shop standards — required kit & tool accountability. Tool-care and fastener technique per marine service practice; final-torque values always to the engine/component manufacturer spec.
Lesson 2 · On the boat
Cleanliness isn't next to godliness. It's customer satisfaction — and it's why this owner calls ESI back instead of the shop across the water.
You represent ESI the moment you step aboard, and the owner grades you before you've turned a wrench. The standard is simple and non-negotiable: ESI blue shirt, black cargo pants, neat and squared-away appearance. On your feet, non-marring, closed-toe shoes — a marking sole leaves black scuffs on a customer's deck and gelcoat, and an open toe has no business near tools, fasteners, and heavy gear.
Surface protection goes down before you board or enter the space, not after you've already tracked across the deck. Cover the path and the work area so nothing you carry, drop, or kneel on ever touches bare gelcoat or a finished surface.
Keep a rag in hand and mind your handprints — greasy prints on a white deckhead, a hatch, or stainless are exactly the marks an owner notices after you've gone. Wipe as you go, pick up every fastener and offcut, and leave the vessel — and every compartment you open — cleaner than you found it. That is the same standard you'll meet in every service job in this course; this is where the habit starts.
ESI presentation & vessel-protection standard.
Lesson 3 · Context
The same job is done differently depending on one question: is the boat in the water, or up on the hard?
Afloat or on the hard, you bring the tools to the boat — you don't walk back to the crib ten times. Load a folding wagon (ESI's fold for exactly this reason) with the cart and kit the job needs and take it to the slip or the stands in one trip. Same point-of-use, Kaizen thinking as the tool cart: the right things with you, nothing missing, no wasted motion.
Field means the boat is floating. It can be at ESI's own dock or a customer's dock — the rules are the same either way: you represent ESI, so the boarding, presentation, surface-protection, and cleanliness standards all apply (a customer's dock just raises the stakes). Because the boat is in the water you have raw-water cooling available, so you can run the engine — warm it before an oil change, run it up, sea-trial it, and test systems under load.
Shipyard means the boat is hauled out, up on stands and blocking, out of the water. There's a lake hose and some water in the yard, but usually not enough for real engine cooling — and that one fact drives the biggest difference in the work.
ESI field/shipyard practice · never run raw-water-cooled engines dry (Yanmar / Volvo Penta / Mercruiser / Cummins operation manuals).
Lesson 4 · Basic service
Everyone starts here. It looks simple — and it's where a sloppy tech leaves oil in the bilge and a good one leaves the compartment cleaner than they found it.
Warm oil flows and carries the suspended contaminants out with it; cold oil leaves half the dirt behind. How you warm it depends on where the boat is — straight from Lesson 3. Afloat: run the engine up to temperature, then shut down and pull the oil. On the hard: you can't run a raw-water-cooled engine dry, so you warm the sump with the magnetic electric pan heater — about an hour beforehand — never by running the engine.
Most marine engines sit low in the bilge with no reachable drain plug, so we pull the oil up and out through the dipstick tube with a pneumatic (vacuum) extractor rather than crawling under to a plug that isn't there. Warm oil, tube to the bottom of the sump, draw it all out into the extractor.
Spin the old filter off (sorbs and a bag ready — it's full of oil) and confirm the old rubber gasket came off with it. Wipe the sealing face clean. Lightly oil the new gasket, spin the new filter on by hand until the gasket touches, then the manufacturer's final turn (typically about three-quarters of a turn) — by hand, never with a wrench cranked down.
Refill with the grade and quantity from the engine's manual — not from memory, and not "till the stick looks right." Run the engine (afloat, or with proper cooling), check for leaks around the filter and drain, shut down, let it settle, and re-check the level — a filter fills on the first run, so the level drops. Confirm no leaks before the boat leaves.
The same job discipline covers the rest: gear/transmission oil to the manual's grade and level, and on sterndrives the gear-lube change — where milky, coffee-with-cream lube means water intrusion past a seal. Note it and escalate; that's a failing seal, not a normal service. Top and check coolant only against the engine's spec coolant, never mixed types.
ESI service standard · oil grade/quantity and filter final-turn per the engine manufacturer's manual · double-gasket failure and pneumatic extraction per marine service practice.
Lesson 5 · Basic service
Water in the fuel is the number-one reason a diesel won't start. The filter that catches it is the primary — and on a diesel, changing it is only half the job. You have to bleed the air back out.
Fuel passes through two filters. The primary sits in the fuel line before the engine and does the coarse filtering plus water separation — this is the one almost everyone calls the "Racor," after the dominant brand of primary water-separating filter. The secondary is the finer, engine-mounted filter that protects the injection system. You service both; the primary is where the water and the algae show up first.
The primary has a bowl (clear plastic or metal, sometimes with a drain) where water and debris collect below the fuel. Draining the bowl and reading it is a service in itself: clean fuel is bright and clear; water sits as a separate layer at the bottom, and a black or slimy haze is diesel bug (algae) from a wet, sitting tank. Water or growth in the bowl is the finding behind most diesel no-starts and power complaints — note it, because it means the tank, not just the filter, needs attention.
Opening a diesel fuel system lets air in, and a diesel will not start or will stumble and die until that air is bled out. Using the engine's lift/primer pump, bleed in order from the filter toward the injection pump, opening each bleed point until fuel runs out clear and air-free, then closing it, per the engine's procedure. Gas engines are generally self-priming and don't need this — diesels always do.
Racor / primary water-separator service & diesel bleed sequence per the filter and engine manufacturer's procedure; confirm bleed points to the engine manual.
Lesson 6 · Basic service
A two-dollar clamp on a below-waterline hose is the difference between a boat that floats and a boat on the bottom. This is where "good enough" isn't.
The everyday clamp is the worm-drive band. The trap: a clamp sold as "stainless" often has a band that's stainless but a plated screw and housing that rust in salt air, seize, and then shear when you try to service them. Check the screw with a magnet — a true all-300-series-stainless clamp barely attracts it. For hoses that can't take the slotted band cutting in — and for the best marine connections — use PYI/AWAB smooth-band clamps, which grip with a solid, slot-free band that won't slice the hose. T-bolt and constant-torque clamps handle larger and higher-load connections.
Two clamps only give you redundancy if they don't share the same weak spot. A worm-drive clamp doesn't seal at the slotted housing, so offset the two screw housings about 180° — opposite sides of the hose — so the gaps don't line up. Two clamps with their screws next to each other is one clamp's worth of protection done twice.
A clamp is tight when the band is firm on the hose and the hose swells slightly at the band — not when you've buried the band in the rubber. Over-tightening cuts and necks the hose, which fails later right where you crushed it. Inspect old clamps for rust, cracks, and a band cutting into the hose, and replace any that are rusting or embrittled rather than re-torquing them.
Below-waterline double-clamping & hose/clamp practice per ABYC H-2 (hoses and clamps); confirm to the current standard and the boat's configuration.
Lesson 7 · Basic service
In a saltwater yard everything is seized. The skill isn't force — it's the ladder of gentle-to-serious, and knowing the rung where you stop and call fabrication.
Begin at the bottom of the ladder: penetrant (PB B'laster, Kroil) with time to work — soak it, walk away, come back — plus a few taps to shock the threads, then a proper breaker bar with feel from Lesson 1. Most fasteners come with patience, not power.
When penetrant and feel aren't enough, heat breaks the rust bond — and the right heat is the nut/bolt induction heater, not an open flame. Induction heats the fastener fast and locally with no fire, which is what makes it usable on a boat surrounded by things a torch would ruin or ignite.
There is a point where pushing further turns a stuck bolt into a much bigger repair, and a good tech stops there. A sheared-off fastener, a bolt you can feel is about to snap, or anything needing drilling, an extractor, or a re-tap / thread insert is a fabrication job — hand it over rather than snapping it flush or drilling a hole off-angle into a casting.
ESI stuck-fastener protocol · marine metal-free anti-seize standard · induction heat with fire watch per shop safety practice.
Lesson 8 · Basic service
On most marine engines one belt drives the alternator and the water pump. A slipping or thrown belt means no charge and an overheat at the same time.
Replace a belt showing cracks across the ribs or underside, glazing (shiny, hard, slick sidewalls — it's been slipping), fraying or chunking edges, or black rubber dust around the pulleys. Check alignment — pulleys must line up or the belt wears one-sided. And keep oil off the belt: oil contamination makes it slip, stretch, and age fast (a Yanmar-documented failure).
Tension must be enough to grip the pulleys without slipping — but no more, because that same tension is a side-load on the shaft bearings. Too loose and it slips: squeal, weak charging, and (since it drives the water pump) overheating. Too tight and you wipe out the alternator and water-pump bearings early. You verify by pressing the middle of the longest free span with a set force and measuring the deflection. As a field fallback with no number handy, aim for roughly ¼ inch of deflection per foot of span — but always use the engine's own spec when it gives one.
Slide / pry: loosen the pivot bolt and the slotted adjuster bolt, then pry the alternator outward against a solid boss — never against the alternator case or the stator — hold the tension, and lock the adjuster, then the pivot. Screw-adjuster: a threaded adjuster walks the alternator out a controlled, repeatable amount — loosen pivot, turn to set, lock. Idler: an adjustable idler pulley sets tension without moving the alternator. Re-check deflection after everything's locked down.
| Engine (typical) | How you set the belt |
|---|---|
| Yanmar small diesels (2GM/3GM/3YM/4JH…) | Manual V-belt by deflection — press midpoint at ~98 N (10 kgf): 6–8 mm new, 8–10 mm used. |
| Volvo Penta gas (5.0/5.7/8.1) & Mercruiser gas | Serpentine with an automatic tensioner — no manual deflection; read the tensioner's index / wear marks. |
| Cummins (QSB/QSC) & Volvo D-series diesels | Poly-V with a spring-loaded automatic tensioner — confirm it moves freely and sits in range; replace the tensioner when out of marks. |
Deflection per Yanmar 2YM/3YM service manual (98 N; 6–8 mm new, 8–10 mm used); automatic-tensioner practice per Volvo Penta, Mercruiser & Cummins marine service. Always confirm to the engine's own manual.
Lesson 9 · Basic service
The most-changed part on a saltwater boat is the one that's supposed to disappear. Reading an anode tells you whether the whole boat's corrosion protection is working.
Put two different metals in salt water, connect them, and the more-active one corrodes to protect the other — that's galvanic corrosion. A boat's shaft, prop, strut, rudder, and drive are a mix of metals sitting in a conductive electrolyte, so we give the current something cheaper to eat: a sacrificial anode, bonded to the running gear, that corrodes first and is designed to be replaced. A healthy anode being consumed means the system is working; a shaft or prop showing pitting means it isn't.
| Water | Anode |
|---|---|
| Salt | Zinc — the traditional saltwater anode, or aluminum (below). |
| Salt & brackish | Aluminum — now the common choice: it protects in salt and brackish, lasts longer, and is less toxic. Our Anacortes/La Conner waters suit aluminum well. |
| Fresh | Magnesium — the only anode active enough to protect in fresh water; it's eaten quickly in salt, so it's fresh-water only. |
Replace an anode at about 50% consumed — waiting until it's gone leaves the running gear unprotected for the tail of the season. But read the rate, too: an anode that's gone in weeks, or crumbling, is telling you something bigger — usually stray current from a wiring fault or a neighbor's boat at the dock, which eats anodes and then metal fast. A too-fast anode is a finding to escalate, not just a part to swap.
Galvanic protection & anode selection per ABYC bonding/cathodic-protection practice; confirm anode material to the boat's water and running-gear metals.
Lesson 10 · Bridge to Shaft Technician
The coupling is where the engine ends and the running gear begins. Getting it off cleanly is a real skill — and knowing that alignment is someone else's course is part of it.
The shaft coupling bolts the transmission (gearbox) output flange to the propeller shaft — it's the joint that carries engine torque out to the prop. Couplings are either keyed with set screws onto the shaft, or split/clamp style. It's the bridge point between the engine you've been servicing and the running gear, which is why this lesson opens the door to the Shaft Technician course.
Coupling R&R start & shaft-protection practice; full shaft service and alignment per the ESI Shaft Technician course and ABYC P-6-2021 alignment practice.
Course complete
Ten real starter jobs, done the ESI way — tools and safety, boarding and cleanliness, field vs shipyard, oil and fuel, hose clamps, stuck fasteners, belts, anodes, and the coupling that bridges into driveline work. Pass all ten lesson quizzes at 80% to complete the course.
Remember the through-line under every job: cleanliness is customer loyalty, no idle time on the customer's clock, marine metal-free anti-seize only, label every filter, and if it looks right, it flies right — if it doesn't, escalate to the lead. From here the path runs into the drive-type courses (I/O and Outboard) and Shaft Technician.