Engines
There are basically 3 types of engine configuration to be found on the
Evolution 26.
Outboard Motor on Transom
This is perhaps the simplest configuration. It is particularly well
suited to racing boats, as a small (say 5HP) engine can be used to get you out
to the start line. This can then be raised up, leaving a very streamlined
hull underneath. Some people remove the engine and put it inside the cabin
with the anchor when racing to keep the weight off the ends of
the boat (the keen ones!).
The advantages of this configuration are:
 | The propeller can be raised out of the water completely when racing to
reduce drag. |
 | Bottom of the boat is smooth. |
 | Prop won't get damaged when drying out. |
 | Can take the engine home in the winter for a service. |
The disadvantages of this configuration are:
 | Propeller can come out of the water losing drive in a rough sea. |
 | May come out of the water when motorsailing on port tack. |
 | You can't use prop wash on the rudder to manoeuvre the boat in a tight
berth (although you may be able to steer the engine) |
 | Vulnerable to theft. |
 | Not ideal for cruising as you will need at least an 8hp engine. Only
really practical to go for a 2-stroke mounted on the transom as a 4-stroke 8hp
will be too heavy. |
 | Difficult to lift over the pushpit to store in the cabin. |
 | Difficult to stop the boat in reverse. |
Outboard Motor in a Well
Many Evolutions including mine have a well on the centre line for the
outboard.
The advantages are:
 | Weight is further forward than if the outboard is mounted on the transom. Can therefore
fit a quieter and more fuel efficient 4-stroke (mine does better than 2 litres
per hour at 5.5 kts) |
 | You get the benefit of prop-wash on the rudder for tight manoeuvring |
 | Outboard less prone to theft as it isn't as visible as an outboard on the
transom. |
 | Can be raised slightly to prevent prop touching ground when drying out
(see centre picture above) |
 | The well forms a big cockpit drain. Cockpit clears instantly if you
take a wave. |
 | Can take the engine home in the winter to service. |
 | Prop stays in the water when it's rough. |
 | Can easily clear a fouled prop. |
 | Certain amount of steerage from the engine. |
 | Outboard can still breathe (it's not in a locker) |
 | Some battery charging from engine |
 | Easier to work on if it breaks down than a transom mounted engine whilst
at sea. |
The disadvantages are:
 | Difficult to lift the engine out completely when racing. Leaving it
in (particularly in light winds) causes drag from the prop, even if it is left
to spin. |
 | Can get fumes if there is a following wind. |
 | Can be noisy (less so with 4-stroke) |
You can lift the outboard out completely and fit a plug in the well to
streamline the bottom of the boat when racing, but if you have an 8HP or 10Hp
4-stroke outboard then it is very awkward and heavy. I don't usually
bother!.
Inboard Diesel
The inboard diesel with a folding prop is probably the most desirable option.
Due to the age of the boats, most have had the original BMW D7 or D12 single
cylinder engines replaced by now. A good replacement option is the Beta Marine 12hp.
7Hp is a bit underpowered for the Evolution.
The advantages of an inboard diesel are:
 | Reliability |
 | Simplicity |
 | Better for cruising |
 | Good battery charging |
 | Very little drag with a folding prop |
The disadvantages are:
 | Folding prop is unprotected and sticks in the mud when drying out.
|
 | Prone to damage to prop or P bracket |
For me, the outboard in the well is fine as the boat dries out regularly.
I would say however that if you don't need to dry the boat out then the inboard
diesel with a folding prop is a better proposition. Many of the Evolutions
that originally had either an outboard on the transom or in a well have since
been converted to inboard diesel.
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