Engines: Inboard

Page updated: 6 April 2009

Go to Top Unofficial Inboard Engines

Boats with the official inboard engine rarely come on the market and not everyone likes outboard engines, some, because they find them difficult to start, others because an engine mounted off the centre line offends.

Here we see two boats with radical surgery performed on their cockpits in order to accommodate engines that attempt to solve some of these issues. Please use the Forum if you can provide more information about either of these boats or can provide further examples.

Go to TopSkylark

At first glance all that sets Skylark apart from the general run of aging SeaHawks is the garish colour scheme. The cuddy round the cabin door, the porthole within the hatch and even the lifting rudder, all might catch your eye. However, these are normal enough extras to be found on any older boat. What sets Skylark apart is undoubtedly the shaft and propeller emerging from under the hull...

Skylark showing its various non-standard features

Close up, you see what appears to be the shaft of a conventional outboard motor. It was surprising to find the person sending the photographs describing the installation as a "Saildrive", but looking again at the photograph you notice an engine exhaust near the transom, which confirms it is not an outboard that has been mounted in the middle of the cockpit.

Close-up of the underside of Skylark, showing the engine shaft and propellor

The huge box filling cockpit confirms that it is something bigger than the conventional 4hp outboard engine hiding beneath. When questioned, the correspondent looked up his notes and confirmed that the owner had told him it was, indeed, a Saildrive with 7.5hp four stroke petrol engine mounted inboard.

Skylark's cockpit viewed from the transom

In January 2006 the boat was reported to be in the Conwy area of North Wales. If you spot it, and can find out more from its owner, do use the Forum to pass the information on!

Go to TopOdysee 2

This Dutch boat was for sale when these pictures were submitted. They display two interesting features: the vertically split cabin door and engine mounted within the cockpit. Here, it is the engine which is of interest.

Dutch Boat with Adapted Cockpit

In order to accommodate the engine, the stock of the rudder has been raised by a significant margin. Although it is not immediately obvious from the first picture, the one below shows that the tiller now reaches to a point virtually level with the cabin roof.

Dutch Boat with Adapted Cockpit

Go to TopCommentary

It is true that some people find that it is too easy for a main sheet to foul an outboard engine when it is mounted on the transom and prefer an inboard to remove that risk. However, one advantage of an outboard over an inboard motor is that the propeller can be easily lifted out of the water, so reducing drag when not in use, and if you mount the engine on a lifting bracket then you may also be able to lift the engine vertically. This has an advantage for river sailors that like to use every inch of water as one of the problems with tilting an engine to lift the prop clear of the water is that you end up with a couple more feet of overhang, which can easily catch reeds and braches on the bank.

However, both the installations shown here would appear to prevent either method of lifting the prop so they must spoil sailing performance. Perhaps this does not matter for those who cruise in open waters not anxious to get every half knot out of the boat.

Neither does either installation have the advantage of the official inboard engine, which is placed well forward and lower in the cockpit, much nearer the boat's centre of gravity.

Almost the only advantage of these installations is that they place engine weight on the centre line of the boat and the propeller immediately in front of the rudder, improving lateral balance and steering when under power. Are these benefits of any value when set against the disadvantages of loss of cockpit capacity or the raised tiller position that result? This latter, surely, cannot provide for comfortable helming of the boat?

Please use the Forum if you feel these comments are unfair or lack understanding of their benefits.

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