Beneteau twin sterndrive

You’ve heard the sterndrive horror stories… thousands spent on repairing transoms and other components – but how does something like this happen?

First, if you need clarification of what a sterndrive or shaft-drive is, check out one of our first articles here.

When you’re looking at a 30-35ft boat in the $80-120k price bracket, you’re likely going to run into a lot of sterndrive petrol packages. But what does that even mean? Usually they tick all the boxes, having an immaculate interior, generator, and sometimes they’ll even have air-conditioning. So, what’s the downfall?

With any sterndrive, there are a number of additional parts that live in the water such as bellows, universal joints, steering rods, bushes, transom assemblies and trim rams – which a shaft-drive vessel doesn’t have to worry about. Surely, you’d think that would mean they cost more, but not necessarily. A sterndrive is mass produced and very popular, meaning they cost less initially. There are going to be some trade-offs in the long term, such as maintenance as they will need to be anti-fouled, and the cleaned internally for barnacle growth. It’s also common to expect between 10-15 years out of a well-used sterndrive and transom assembly, and then it’s a matter of continual repairs or replacing it once and for all.

Sterndrives are a faster and more efficient design, as they are mounted to the rear and produce less drag. They use less fuel than a shaft-drive, and can be trimmed up in shallow waters, allowing you to beach your boat. The trim can also be adjusted whilst running to help with the correct bow angle you desire for certain conditions.

So, what about shaft-drives? Are they all bliss? To a certain degree, shaft-drives are a lot less maintenance. Now, this isn’t to say that a 15 year old shaft-drive boat wont need any maintenance – there are still numerous parts such as skeg bearings, rudders, bonding straps and seals that wear-out and need to be replaced. The distinct advantage is that they’re cheaper and more readily available, having a longer running life.

But what does it cost to swap one of these transom assemblies out?

Cost Comparison

Let’s do a comparison using a 15 year old 32ft boat as an example. One boat is a shaft or V-drive, and the other is a twin sterndrive. Both boats have 500 hours, and for arguments-sake need some maintenance. From our experience, we will consider the differences in maintenance considerations at 10-15 years for both shaft-drive and sterndrive. 

Shaft Drive Stern Drive

Parts

Shaft Bellows & Seals 

$500-700 per side (x2)

Transom Assembly 

$5,000-6,500 per side (x2)

Parts

PSS Rudder Seals 

$500-700 (x2)

Sterndrive & Transom Package

$12,500-15,000 per side (x2) 

Parts

Skeg bearings $200-400 per side (x2) $7,000-9,000 for a new sterndrive

Parts

Bonding straps $200-300

Services

Balance props & rudders $2,000-3,000 for both sides

Total Labour

Best case: 21 Hours $2,200

Worst case: 30 Hours $3,300 Labour calculated at $110 per hour

Best case: 27 Hours $2,970

Worst case: 40 Hours $4,400

Labour calculated at $110 per hour

Total Cost

Best case: $6,690

Worst case: $10,200

Best case: $12,970

Worst case: $27,970

Worst case with new sterndrives: $34,400

Figure 1 – Estimated costs of repairs

As you can see, the cost of repairing a sterndrive is predominately parts, but it also includes more labour, because every time you work on the transom the motor needs to be removed. Every boat will be different, and that’s why the labour amount will change. All of these costs are NOT incorporating any engine work, slipping costs and days on the slipway, which can add up significantly as well. These costs will vary depending on the boat design, as some vessels may require floors and seating to be removed to gain access. It will be cheaper to get all the work done at the same time, as opposed to bit-by-bit as you will have to pay for slipping each time.

 

Mercruiser Sterndrive

On the other side of the argument, a shaft-drive boat will usually attract a higher price, but not always. A new Sea Ray in V-Drive is $17,000 as an additional option when new. Sometimes a price of $20-40k more is asked, but this may also include a diesel. It’s near impossible to find a shaft-drive boat in the 22-28ft range and they’re usually less manoeuvrable with one engine. Owning a single sterndrive can be much more acceptable cost-wise compared to a twin sterndrive, but it will still cost more than an equivalent shaft-drive. 

Allowing all the engines to be mounted to the stern does have it’s design, speed and economical advantages – but they really hurt when it comes to second hand maintenance costs. Ultimately if sterndrives were not invented we would have far fewer vessel designs.

If you’d like to learn about the differences between sterndrive and shaft-drive powered vessels, please don’t hesitate to get in touch with us. We can talk you through the buying process, and also give you some tips and tricks on what to look out for on initial inspections. Once you’re ready to make a purchase, we can provide a comprehensive survey and mechanical inspection. You can call us on 02 9188 5182 or shoot us an email at info@boatbuy.com.au.