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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:

bulletThe propeller can be raised out of the water completely when racing to reduce drag.
bulletBottom of the boat is smooth.
bulletProp won't get damaged when drying out.
bulletCan take the engine home in the winter for a service.

The disadvantages of this configuration are:

bulletPropeller can come out of the water losing drive in a rough sea.
bulletMay come out of the water when motorsailing on port tack.
bulletYou 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)
bulletVulnerable to theft.
bulletNot 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.
bulletDifficult to lift over the pushpit to store in the cabin.
bulletDifficult 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:

bulletWeight 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)
bulletYou get the benefit of prop-wash on the rudder for tight manoeuvring
bulletOutboard less prone to theft as it isn't as visible as an outboard on the transom.
bulletCan be raised slightly to prevent prop touching ground when drying out (see centre picture above)
bulletThe well forms a big cockpit drain.  Cockpit clears instantly if you take a wave.
bulletCan take the engine home in the winter to service.
bulletProp stays in the water when it's rough.
bulletCan easily clear a fouled prop.
bulletCertain amount of steerage from the engine.
bulletOutboard can still breathe (it's not in a locker)
bulletSome battery charging from engine
bulletEasier to work on if it breaks down than a transom mounted engine whilst at sea.

The disadvantages are:

bulletDifficult 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.
bulletCan get fumes if there is a following wind.
bulletCan 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:

bulletReliability
bulletSimplicity
bulletBetter for cruising
bulletGood battery charging
bulletVery little drag with a folding prop

The disadvantages are:

bulletFolding prop is unprotected and sticks in the mud when drying out. 
bulletProne 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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