It’s a boat. Things will break. Having spare parts on board, especially for longer-distance cruisers, is an important consideration. What you keep on board for spares will vary greatly depending on the type of boat, the age of your boat, how much you cruise, where you cruise, and whether you know which end of a screwdriver goes on the screw.
In this article, I will discuss the considerations regarding which spare parts to carry in various scenarios and provide some food for thought on why you might consider each one.
I will start with a disclaimer. My mechanic is often referred to as “The Prophet Of Doom And Gloom,” which has affected my outlook on carrying spare parts. If he had his way, I’d carry two spare engines, a spare generator and tow an extra hull behind me “just in case.” Also, I’m a tinkerer and love to putter around on my boat, so that influences my recommendations as well.
General Considerations On Carrying Spares
Your Boat Type
If you have a small day boat, a center console fishing boat, or a cuddy cabin, the amount of space available will determine how many tools and spare parts you can carry. If you have an outboard, carrying a spare fuel filter and a spark plug might be sufficient. However, for larger and more complex boats with inboard engines and possibly generators, your list of spare parts will be more extensive.
When working on an engine, you should consider the type of fuel it uses. If you have a diesel engine, it is relatively safe to work on because spilled diesel is easy to clean up and doesn’t pose a significant hazard. On the other hand, gasoline presents more of a hazard. Spilled gas can quickly vaporize and concentrate in enclosed engine spaces, creating an explosion hazard. If you are working on a gasoline engine, you must be extremely careful to avoid spills and anything that can create a spark.
The Age Of Your Boat
The older the parts on your boat, the more likely they are to fail. If you have a shiny new boat, the number of potential failures is probably (hopefully) limited. Having a new boat is no guarantee that nothing will break, but the chances are lower, and there are still maintenance items.
On the other hand, if you are cruising around in a classic 1978 Marine Trader 40, then you probably want to have a few spare parts on hand. The older the boat, the more likely that a part will fail. With proper regular maintenance, you can mitigate many of these issues, but at some point, something will fail.
Older boats may face challenges when it comes to finding replacement parts. Many boats from the 1970s, 1980s, and 1990s have engines and boat manufacturers that are no longer in business. Some popular engines from that time, such as Ford Lehman and American Marine Diesel, are no longer being produced. Other engines from that era have also been discontinued. While parts for these engines may be available from third-party manufacturers, new-old-stock, or remanufactured parts, obtaining them can be difficult and lead times long. It’s a good idea to keep spare commonly replaced parts like water pumps, balancers, specialized hoses, and commonly used gaskets on hand to minimize downtime in the event of a breakdown.
Where You Cruise
You will find plenty of mechanics and boat yards nearby if you are cruising along the Atlantic Intracoastal Waterway (ICW), around Florida, or the Gulf Coast. It is easy to arrange parts deliveries to these areas, with next-day service available almost everywhere. Additionally, in case of emergencies, SeaTow and Tow BoatUS provide good coverage in these areas.
If you plan to cruise to more remote areas, such as those along the Great Loop, it’s important to consider carrying a larger selection of spare and maintenance parts. Once you pass New York City on the Hudson River and venture into areas of Canada, the Illinois, Mississippi, and Ohio Rivers, sections of the Tenn-Tom Waterway, and especially Bermuda, finding mechanics and parts becomes more challenging. In these areas, towing services like SeaTow and Tow BoatUS may have limited or no coverage. Therefore, having spare parts available can be a lifesaver if you experience a breakdown in these areas.
Even for newer boats, it can be beneficial to carry spare maintenance items such as oil and fuel filters, belts, branded engine oil, and coolant (to protect your warranty). The cost of these items in Canada and the Bahamas is much higher than in the US, and few locations will have them on hand. Shipping from the US to foreign countries can be expensive, and customs can cause delays.
How Much You Cruise
It may seem counterintuitive, but using your boat more often can actually help prevent equipment failure to a certain extent. Boat engines and systems benefit from the regular flow of water through them. Diesel engines perform better when they are run and warmed up. Running your engine ensures that internal components stay lubricated with oil and reduces the accumulation of moisture that can lead to corrosion of internal components. In addition, running the engines for extended periods on a regular basis helps to dry out engine rooms and bilges, preventing the build-up of condensation and mildew.
I say to a point because general wear and tear will occur, especially on parts such as wear parts such as impellers, belts, pumps, and injectors. If you are a full-time cruiser or a live-aboard (who doesn’t just sit in a marina for months/years at a time), you will likely experience fewer failures than the boat that sits for months or years at a time.
How Handy You Are With DIY
Some people are gifted mechanics. “Oh, my engine needs to be torn down and rebuilt? Great, I’ll take care of that over the weekend!” For others, if you give them a screwdriver, they will put an eye out! Most boaters fall somewhere in between.
The more handy you are, the more issues you can resolve, at least temporarily, so that you can finish your day of cruising. Also, performing your own maintenance improves your understanding of your boat’s systems and saves you money!
I handle most of my own maintenance tasks, but for larger jobs, (like having my engines rebuilt) I rely on professionals. I make it a point to observe their work without getting in their way so that I can learn and take care of similar issues in the future. Most mechanics focus on getting the job done and leaving the boat, especially if they have agreed on a price beforehand. During my oil changes, I take the opportunity to inspect the engine room for any other potential problems. Most mechanics might not notice or report a small leak near the water pump. However, for me, it indicates that something might be on the verge of failing. It could be as simple as tightening a hose clamp, but at least I know about the issue. So, when the temperature alarm goes off on that engine, I’ll remember, “Oh yes, I should have checked that water pump that was dripping.”
Tools To Carry
What tools you carry are directly proportional to the amount of DIY you plan to do and, to a slightly lesser extent, the amount of storage space you are willing to dedicate to them. For most, a simple tool kit will do.
I buy most of my boat tools from Harbor Freight (HF) and Amazon (not sponsored!). The quality is fair, and they are relatively inexpensive. Even expensive tools rust and break. I can buy ten sets of Harbor Freight pliers for the cost of one Snap-On. I’ve included links to some recommended items at HF. Note: Many of these links change frequently. If a link is broken, search for the description on the site or Google.
Here are the basics I recommend.
- 3/8″ Socket Set. Get one that is both SAE and Metric. Having deep sockets as well as shallow ones comes in handy. Pittsburgh Set with 1/4, 3/8, and 1/2″
- 1/4″ Socket Set. A small set of sockets with a small handle is great for getting into tight spaces. 1/4 Inch Drive 46 piece Socket Set on Amazon
- Combination Wrench Set. SAE & Metric. Pittsburgh 22 Piece Wrench Set
- Strap Wrench. Great for oil filters and strainer covers. Pittsburgh Strap Wrench Set
- Adjustable Wrench. When nothing else fits! Pittsburgh Adjustable Wrench Set 3-Piece
- Wire Strippers. For wiring repairs. Pittsburgh Multi-purpose Stripper, Crimper Cutter
- Screwdriver Set. Regular & Phillips with a range of sizes, including stubby. Pittsburgh 22 Piece Screwdriver Set
- Torx Screwdriver Set. A small set of screwdrivers with Torx bits. Pittsburgh 26-Piece Ratcheting Screwdriver Set
- Mini Screwdriver Set. For fixing glasses and other little screws. Pittsburgh Multi-Bit Precision Screwdriver Set, 34-Piece
- Pliers Set. Include: grove joint, needle nose, slip joint, long nose, wire cutter, and lineman’s pliers. Pittsburgh 6-Piece Pliers Set
- Locking Pliers. (Vice Grips) Great for clamping or getting off stuck bolts. Pittsburgh Locking Pliers
- Rubber Mallet. A rubber mallet is good for “gently persuading” stuck items. Pittsburgh 1 lb. Rubber Mallet
- Tape Measure. For measuring! Pittsburgh 25 ft. x 1 in Tape Measure
- Utility Knife. With Extra Blades! Folding Lock-Back Utility Knife
- Multimeter. A simple one will do. Watch a HowTo Video if you are new. AstroAI Multimeter on Amazon
- Magnetic Wide Angle Flashlight. Multi-beam. Braun Rechargeable Foldable Work Light or Amazon
Some other items to consider
- Oil Filter Wrench
- Large Waterpump Pliers (Slip Joint Pliers)
- Spring Loaded Pick-up Claw
- Magnetic Pickup Tool
- Micrometer
- Battery Powered Drill (with screwdriver and drill bits)
- A small Wet-Vac. Many like the Bucket Head used with a 5-gallon bucket. Great for quick cleanup and for sucking water out of bilges etc. Home Depot
Keep your tools in watertight containers or toolboxes. Look for one with a rubber gasket seal. Keeping a moisture absorber pack that can be recharged in the microwave inside will help keep your tools from rusting. Also, a quick wipe-down with a WD-40 sprayed rag from time to time will help.
General Supplies
Having some general repair supplies on hand can be helpful. None are expensive. Most are available at Amazon, Harbor Freight, and hardware stores.
- Plastic Black Electrical Tape
- Duct Tape
- Rubber Self-Sealing Repair Tape. Amazon
- 4″, 8″, and 12″ zip ties
- Super Glue
- Lock-Tite
- Selection of stainless steel nuts, bolts, & washers. Amazon
- Heat Shrink Wire Connectors. Amazon
- Selection of Marine Grade Heat Shrink Tube. Amazon
- 10-ft of 22 gauge. 2 conductor marine wire – Sold by the foot at WestMarine
- 10-ft of 14 gauge. 2 conductor marine wire – Sold by the foot at WestMarine
- WD-40 (a small can is fine)
- Oil Absorb Pads (10-20 15″ x 15″ minimum)
- Stainless Steel Hose Clamps – A selection of sizes 1/4″ to 2″. Amazon
- Spare Fuses – Based on the type used on the boat. Glass and/or Automotive.
- RTV Gasket Maker – A small tube for making gaskets and general sealing.
- 3M 4200 Fast-Dry – 3 oz. tube – Removable, seals underwater, good for quick fixes
- Rubber Gloves – Several sets to keep your hands clean.
What Spares To Carry
Since the specific size, brand, and type of spare will vary greatly depending on your boat, I’ll list suggested supplies broken down by area. Items with an “*” are my suggestion for minimum spares. If you have two engines, then double the quantities.
- Fuel System
- *Primary Fuel Filter (Racor’s) – Qty: 2 sets
- *Generator Fuel Filter – Qty: 2
- Main Engine
- *Oil Filter – Qty: 2
- *Engine Belt – Qty: 1
- *Water Pump Impeller – Qty: 1-2
- *Engine Oil – Qty: 1 Gallon (minimum)
- *Engine Coolant – Qty: 1 Gallon (minimum). Premix if necessary.
- Engine Fuel Filter – Qty: 1
- Engine Anode (Set) – Qty: 1-2
- Transmission/Gearbox/Pod Drive
- *Transmission Oil Filter – Qty: 1
- *Transmission/Gearbox Oil – Qty: 1 Gallon (Minimum)
- Stuffing Box Packing (if used) – Qty: 1 Package
- Generator
- *Engine Oil Filter – Qty: 1-2
- *Primary Fuel Filter – Qty: 1
- *Engine Belt – Qty: 1
- *Water Pump Impeller – Qty: 1
- *Engine Oil – Qty: 1 Gallon
- *Engine Coolant – Qty: 1 Gallon. Premix if necessary.
- On Engine Fuel Filter – Qty: 1
- Engine Belt – Qty: 1
- Engine Anode (Set) – Qty: 1
- Running Gear
- *Propeller Shaft Anode (Zincs) – Qty: 1 Set
- *Propeller Tip Anode – Qty: 1 (if used)
- *Rudder Anode – Qty: 1 (if used)
- *Trim Tab Anode – Qty: 1
- *Main Transom Anode – Qty: 1
- *Bow/Stern Thruster Anode – Qty: 1
- Spare Propeller – Qty: 1 Set (Extremely helpful if you can afford it and have room to store them)
- Battery/Electrical System
- *Distilled Water – Qty: 1 Gallon (minimum) (If used in your batteries).
- High-Amperage Fuses – For Thrusters, Windlass, Starter if equipped.
- Dinghy Motor
- Engine Oil – Qty: 1 Quart
- Lower Unit Oil – Qty: 1 Quart
- Spark Plug – Qty: 1 (for each cylinder)
- Other Systems
- Hydraulic Steering Fluid – Qty: 1 Quart
- Hydraulic Fluid for Thrusters/Stabilizers – 25% of total capacity (if equipped)
- Bilge Pump – Qty: 1 (spare for main bilge pump)
- Float Switch – Qty: 1 (spare for main bilge pump)
What you choose to carry is up to you, as well as the space available on your boat. These are suggestions. You may find that other items are more important based on your specific boat and cruising style.
The most important takeaway is to think about what you need for onboard tools and spares. Even if you don’t stock up, you will have an idea of the types of parts and supplies might be required when a repair is required.
One final bit of advice. If you rely mostly on mechanics and boat yards, keep a stock of $50 and $100 bills handy. Dolling out a tip, especially before the mechanic starts work, will go a long way toward a professional job in a timely fashion.
What do you carry for tools and spares? Did I forget something important?
Let us know in the comments below! 
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