The most important points on the checklist for buying a used boat are the engine, gearbox, electrics, upholstery, tarpaulins and the essential test drive. First impressions are important in all respects. That's why you should never inspect a boat on your own. Quote from the proverb collection: "Four eyes see more than two."
Don't be afraid to ask why the boat should be sold. If you only get evasive answers, scepticism is the order of the day. Caution is also advised in dark corners, as sufficient light is required for a proper inspection. If tarpaulins or canopies are hanging at "half seven" or are even torn, metal is rusting and the boat is dirty and untidy, you can generally assume that it is in a poor state of maintenance. If there is also a musty odour below deck or if the crammed cabins do not allow a proper "inspection", then the matter is already over. If you speak to the seller about any points of criticism you find, you should not accept the argument "It's all just minor things that can be fixed quickly". After all, if these minor issues could really be repaired quickly, the seller could have done it himself long ago. All in all, a good boat is also in good condition.
Have invoices shown
Have repairs and maintenance work been carried out on the hull, engine, drive or electrics? Don't worry, this doesn't mean that repaired boats are no good. On the contrary, with an older engine, regular maintenance or a general overhaul carried out shortly beforehand can even count as a plus point. Provided that the work was carried out by recognised experts. The decisive factor for all repairs is proof of who carried them out. If the seller does not have such invoices, caution is advised: ask for the reasons. If the invoice only shows the materials, the question remains as to who carried out the repairs. This may have been the owner himself or an "acquaintance". One thing is certain: neighbours and friends are often the cheaper, but unfortunately not always the better craftsmen. Therefore: "The bill, please."
- Tip: No compromises. If the points of criticism outweigh the advantages at the first visual inspection, it is better to keep your hands off the boat.
The most important tips for test drives
As with buying a car, there is no substitute for testing a boat yourself - especially a second-hand one. If the boat is in the water, there are no discussions about crane or slip costs. It becomes a little more difficult when the test candidate is high and dry in the showroom or winter hall. Perhaps in the furthest corner. If in doubt, there is no other option but to postpone the test ride until spring.
The question remains: "How do I take a test drive?" Certainly not alone. You can find out what to look out for in terms of drive technology during the "dress rehearsal" under the heading "Engine and drives".
To gain practical driving experience, the fuel and water tanks must be full. Or do you always want to drive with an "empty" boat later on? It's best to start slowly. This means that you should first try out the course stability in displacement and the manoeuvring characteristics. If there is no rough water, the displacement sailing test is already over.
In order to assess the handling behaviour at high speeds, the famous (throttle) lever must be placed on the table for planing and semi-planing boats. Semi-planing boats can run out of control when travelling at high speed on sloping waves, which is nothing unusual for this type of boat. If it doesn't, so much the better. Even without trim tabs, a glider must transition quickly from displacement to planing speed. If it has difficulty doing this, which can be recognised by the fact that the stern sinks low and the bow points into the sky for a long time, the cause may be (too) weak motorisation. As a result, the engine(s) are constantly being tormented, which certainly does not prolong their life. Under certain circumstances, the boat may not be able to glide at all with holiday luggage. This is another reason why it is so important to load the boat correctly during the test drive.
If the boat glides, you should steer it into tight bends and circles as a test (even if the seller grumbles). The steering should remain smooth, the hull should not catch (brake abruptly sideways without warning) and the propeller should not gasp for air. The latter can be recognised by the fact that the engine then suddenly revs up. In rough water, course stability and a smooth entry into the waves are particularly important.
Steering
There are tiller steering, cable, cable, servo and hydraulic steering systems. With all of them, it is important that they move smoothly in every situation and do not have too much play. Smoothness is checked while travelling, as the steering forces on the rudder blade, Z-drive and outboard motor are significantly higher than when stationary. Causes of stiff steering are overtightened set screws (small outboards), corrosion and faults in the transmission mechanism. Hydraulic steering systems must be checked for leaks. If the steering system has too much play, this may be caused by worn bearings or bolts, incorrect adjustment or a lack of hydraulic oil.
Wooden boats
There are two different hull materials for wooden boats: solid wood and waterproof glued plywood. In contrast to plywood boats, older boats made of solid wood must be left in the water for a while in spring before the first trip so that the wood swells and the hull becomes watertight. One thing is clear: both types of boat are very difficult - or even impossible - to assess without specialised knowledge. The reason: Rotten and dilapidated areas are not always clearly visible, especially if they are hidden under a coat of coloured paint.
In the case of "natural lacquered" (clear lacquer) wood, grey or dark stains indicate that moisture has penetrated. However, it is difficult for the average consumer to judge how badly the wood under the varnish has been affected. The question is then: Does the wood need to be replaced or is thorough sanding and repainting sufficient?
Tip: With wooden boats, it always pays to consult a specialised expert.
Plastic boats
You put a car on the lift, but what do you do with a boat? Of course, buying a boat without having seen the underwater hull is always a risk.
Inspecting the "underbody" of trailer boats is not a problem. Heavy boats have to be craned for this. This costs money, which the buyer usually has to pay. The better solution: If a purchase contract is concluded, the seller pays the crane operator - or you share the fun.
Once the boat is ashore, the main thing to look out for is bubbles, flaking and cracks in the gelcoat, which is not only meant to shine, but above all to protect the laminate of polyester resin and glass fibre mats against water and UV rays.
But be careful, not every blister is automatically called "osmosis". The nightmare of all plastic motorboat drivers can be recognised by a sour smell after the bubbles have burst. A small number of them can usually be repaired by yourself, special repair kits are available from specialised dealers. If the hull is covered in bubbles, only a complete repair by a specialist will help. And that costs a lot of money. It can add up to 1000 euros per metre of boat length. Peeling underwater paint indicates inadequate treatment of the surface. It has not been sanded properly, the wrong primer has been chosen or the wrong "antifouling" has been applied. Hairline cracks, for example on the transom, are an indication that the hull structure has been subjected to excessive loads caused by over-engineering. If large cracks appear in the gelcoat, ramming or repair areas where the filler no longer adheres properly may be the hidden cause.
- Tip: Surfaces that look like orange peel indicate "accidental damage" caused by painting.
Boats with steel hulls
Modern processing methods, primers and two-component paints have reduced the corrosion problem for steel yacht builders to a healthy level. But not all steel boats are modern. This is why the following still applies today: an "iron steamer" is not only at risk of rusting on the outside, but also on the inside. Sweating and bilge water, which may be "enriched" with salt, oil and fuel, place high demands on the primer and paint. It is difficult to inspect the steel inside due to panelling and insulation. If you want to know more about bulkheads, stringers, frames and the important weld seams, an expert must be consulted.
The outer skin, on the other hand, is much easier to inspect. Provided the boat is on land, rust dents and stains are easy to recognise. A steel hull can be corroded not only by rust, but also by galvanic corrosion. In particular, the area around metal through-hulls and the propeller and rudder shafts must be checked carefully. Sacrificial anodes made of zinc or magnesium are usually installed at these critical points. If they look like new even though they are old, they have not worked and the contact surfaces with the hull must be checked.
- Tip: Boats with deep rust pitting require costly refurbishment. Small dents and dings, on the other hand, can be repaired by the owner.
Inflatable boats
The first rule is: never buy a pig in a poke. In plain language: never take delivery of a used inflatable boat in its packaged state. It is also not enough to take a superficial look at the assembled and inflated boat. Instead, the hull, floorboards or plastic hull, stiffeners, transom and accessories must be carefully inspected individually.
Minor scratches on the tube body are of secondary importance, unless the underlying fabric is already exposed. However, there are critical points on every used inflatable boat. The most important are chafed areas on the inside, namely where the floor plates or stiffening strips are in contact with the tube body. Large areas of abrasion are difficult to repair.
Damage to wooden parts is caused by the penetration of moisture. If rotting is detected, the value of the boat is greatly reduced. With plastic hulls, look out for cracks in the gelcoat; scratches can be repaired relatively easily. However, if cracks are found in the transom area, this indicates overloading. In other words, an overly powerful motor was installed and pulled and pushed (too) hard on the mirror. Conclusion: Don't buy it. Although manufacturers guarantee a long service life, boats that are more than ten years old should be examined particularly critically.
- Tip: Do not just inspect the boat and accessories superficially, but check them thoroughly for damage.
The motor should be checked as follows
Whether outboard or inboard, without an intact engine, the best boat is only worth half as much. The layman can only test drive an engine and then visually inspect it. Important: The engine should be cold before the first test start. This is because a warm engine usually starts better than a cold one. If you want to know whether the engine has already been running, simply lay it on by hand. Even when cold, the engine must start quickly and without coughing and spitting. If it is running, you should look out for heavy smoke coming from the exhaust. The rule of thumb here is: white smoke indicates water in the cylinder, dark, almost black smoke is a sign of incomplete combustion, i.e. a faulty fuel system. If the engine emits blue smoke signals, oil is being burnt. The latter is only normal for cold two-stroke engines with mixed lubrication.
Control lamps for oil pressure and alternator must go out immediately after starting. On boats with analogue (pointer) instruments, the charging voltage must be 14 V at around 1500 rpm and the oil pressure must be between 2 and 3 bar when the engine is warm. Important: The cooling water temperature must always remain in the "green range".
- Tip: The engine is the heart of a boat. That's why advice from independent experts is a must for an engine layman.
Propellers, water and oil: what you need to watch out for
When driving at full throttle, the engine speed must be within the range recommended by the engine manufacturer. If there is no indication on board (manual or sticker), it can be obtained from the manufacturer or a specialist workshop.
If the full load speed reached is too low, this is a sign that the propeller is too large or the engine power is insufficient. If the motor is turning too fast, the propeller is too small.
Visual inspection: You cannot look inside the engine without a flexible endoscope (only real professionals have one). A compression pressure diagram provides information about the inner workings. If all cylinders have roughly the same measured values, this is a good sign. Significant differences are an indication of defective piston rings or valves. This means that the engine no longer has its full power. On the outside, look for corrosion, water and oil leaks. Internal leaks, such as a defective cylinder head gasket, can be recognised by starting difficulties (if there is water on the piston, the starter motor pulls with difficulty or not at all), loss of cooling water (dual-circuit cooling) and, in four-stroke engines, also on the dipstick. If the oil on the dipstick is milky or the dipstick is rusty above the maximum mark, this is a first indication of water in the oil. If there is oil in the water, sludge in the expansion tank of the dual-circuit cooling system or if there are coloured spots "in the stream" after the engine has been switched off, the cylinder head or its gasket is defective in the first case and the oil cooler in the second. Caution: Both can result in expensive repairs.
Repair invoices, if they are available, provide valuable information. Oil and water leaks to the outside are easiest to detect after the test drive: Is there a wet and oily bilge that was previously clean and dry? A professional examination of the engine oil provides information on wear and tear and thus the answer to the question "Can the operating hours be correct?". This works for car engines at least. There, as here, inspection and repair invoices provide valuable information on the state of maintenance of the engine.
Drives: What you need to consider
Galvanic corrosion can occur on sterndrives, outboards and shaft systems. Sacrificial anodes, which can be found on the transom plate, bracket and underwater part of sterndrives and outboards, are designed to prevent this. On boats with shaft systems, they are usually located near the propeller and on the rudder blade. If the sacrificial anodes are pitted, this is a good sign, they just need to be replaced in good time. Important: Sacrificial anodes must not be painted over because they will then no longer function. Seized drives and shafts are an indication of inadequate corrosion protection.
Propellers should also be checked for seized areas, but it is even more important to look for severely bent blade edges caused by ground contact. An imbalance in the propeller can ruin the shaft bearings in the long term. The result: stuffing boxes and oil seals become leaky. If water runs into the gearbox through the propeller shaft seal on outboards and sterndrives, this can be recognised by milky (emulsion) gearbox oil. If silvery shimmering particles are found in the oil, this is a sign of (abnormal) wear on bearings or gears. Caution is advised.
Important: The outer rubber parts, such as the bellows on Z-drives, must also be thoroughly scrutinised. They must be tight and must not be porous or even have holes. If water runs into the drive, emulsion and corrosion are the result.
Note: Repairing defective Z-drives can quickly become expensive fun. For shaft systems, check the seal on the stern tube. However, a few drops of water are not a problem. It is important that the shaft and seal do not become hot (place your hand on them). Whether the shaft bearings have too much play can be recognised by vibrations and loud humming while driving. The same applies to the gearstick. You can tell whether the lever moves smoothly and locks noticeably in the "Forward", "Neutral" and "Reverse" positions as soon as you put it down. Sluggish or worn gearsticks should not be accepted. If the sterndrive or outboard can be raised and lowered quickly without jerking or jamming, the power trim is obviously OK.
- Tip: Seized sacrificial anodes are a sign of effective protection against galvanic corrosion. Seized drives, underwater parts, shafts and propellers, on the other hand, signal the exact opposite.
Fuelling system
A keen nose is required when checking the fuel system. In other words, if there is a smell of diesel or petrol on the boat, caution is advised. There is probably something wrong with the fuelling system. Do not start the engine until the fault has been found and rectified. Even "if the air is clean", this does not mean that everything is right, because hoses can be porous and have cracks, especially at the connections. Therefore, check all hose lines for damage and a tight fit. If the tank is installed out of sight under the cockpit floor, the only thing left to do is to trust it. The indispensable standards of a good fuel system include a stopcock, separate filter with water separator, secure fuel filler cap and an engine compartment blower.
The fresh water and faeces tank system is checked for leaks. In addition, water is tapped from all taps to check the function of the drains and the pressure pump. If the pump continues to run at short intervals after all taps have been closed, there is a leak somewhere on the pressure side.
- Tip: On the Baltic Sea, all boats with a pump toilet must have a faeces tank. So check whether such a tank is installed or can be retrofitted without great effort.
Gas system
The gas system may and can only be checked by a specialist. Important: This inspection must be repeated every two years. If everything is in order, there is a sticker, which can usually be found near the gas cylinder or the shut-off valves. Just like the MOT sticker on your car, this sticker shows the next inspection date. This means that one glance is enough to tell you immediately whether the system is still approved. Caution! Missed inspection dates are detrimental to safety and should be made up for as soon as possible
- Tip: Consumers such as cookers, heaters or refrigerators should be checked for proper function even if they have a valid sticker.
Electrics
Electrics are a matter of luck. Says the layman, who doesn't understand a thing when he sees all the colourful wires. Even the otherwise useful wiring diagram doesn't help. Anyone who has not studied the subject in depth can only judge the electrics of a used boat according to two criteria: firstly, function and secondly, appearance.
For the average consumer, the first thing that is important is that everything works. This means switching on all the lights (don't forget the position lights!) and devices one after the other and checking whether everything lights up, honks, wipes and pumps. If everything works, take a look behind the scenes.
Here too, the cables should be properly laid, i.e. bundled and well supported. Protective conduits or closed cable trays are exemplary. Corrosion on switch contacts, plug connectors or the fuse box (every power consumer needs a fuse!) does not have to be dramatic, but it shows a lack of care. Important: Every fuse must be labelled. Fuses should come from the car (replacement at any petrol station) - automatic circuit breakers are even better.
The next step is to check the battery(ies), which should be kept clean and stable; it is important that the capacity (Ah) corresponds to the requirements of the consumers, that the starter and on-board circuits are separate (only a specialist can recognise both) and that the batteries are not too old. The date of installation or purchase can often be found on small stickers. By the way: No battery can do without a main switch.
- Tip: Normal lead batteries should not be much older than three years, whereas maintenance-free gel batteries have a much longer life.
This article is part of the Used boat purchase special. All contents:
- Buying a used boat: The key to success - How to do it right!
- The advantages and disadvantages of used boats
- How to find the right boat
- Typology - The most important types of motorboat
- Boat exchanges: Your guide through the online jungle
- You should look out for these weak points
- Checklists for the test drive and inspection
- How to avoid traps in the purchase agreement
- What new owners need to know
- You need these insurances for your boat
