Hown to install an auxiliary engine

[HarrisonMelecchi]

Hello, I want to install an auxiliary outboard engine myself. Any tips where I can find enough information to do it on this kind of boat? It's a cruiser 26 feet. It's my sister's boat and some people said to us it's simple, so I want to learn how to do it. Any specific support or could be those simple ones we find on Ebay? Long shaft or short? And minimal HP? We want to fix the main engine but it's a bit expensive at the moment for us so it will be only a temporary solution and there's no need to be a powerful oneI. Anyway,  thanks in advance, this group has been so supportive in all my boat challenges. 

[Alan de Enfield]

To determine the leg-length you need to measure the transom height.

 

If you intend to mount it on the steel frame, it may be too high and you will need an XL length. You will be better mounting it on a proper outboard bracket.

 

Assuming it is a small(say 15hp or under) engine the fitting is simply putting the engine bracket over the boat mounted bracket and tightening the clamp screws.

 

Connect up the fuel to a remote fuel tank and away you go.

 

The problem with mounting an out board with such a high transom is how are you going to steer ?

Normally an auxiliary outboard is simply steered using the inbuilt tiller arm, but being so low down the transom that won't work. Possibly a tiller extension arm (or piece of drain pipe) might work, you'd need to try it.

 

You could install wheel steering but that will get complicated and expensive.

 

 

I strongly suggest that you go and have a look at how similar boats have mounted their auxiliary and see if the same can be done on you boat.

 

One example of an outboard bracket.

 

 

 

[Mad Harold]

Fitted a 6hp auxilliary outboard to a Norman I had a few years ago.

It was a longshaft because of the distance from the trapezium mounting to the prop cavitation plate needing to be about level with the bottom of the hull.

There were a few difficulties,first the boat needs to be out of the water,the trapezium mount need to be the correct strength for the outboard.Some makers quote for example,suitable for 10hp two stroke or only 6hp for a four stroke.

The position of the mount is quite critical in that the prop needs to be deep enough,and when the outboard is not in use,you don't want the prop dragging in the water.

The transom will quite likely need a large piece of ply on the inside with the trapezium bolted through with large washers to spread the load.On mine the transom flexed under power untill I fitted the ply.

Because of the angle of the tiller,even a telescopic tiller extension was too steep an angle for effective control,so a "swan neck"tiller will need to be fabricated,along with a longer gear lever.

It was a long frustrating job,and and really of little benefit,except as an emergency engine.

Looking at your boat photo,the towel rail on the transom would have to come off to fit a trapezium mount.

Would it be simpler to have say a 5mm steel plate about 10"×5" welded to the curved bit of the "towel rail"and mount an ex longshaft or perhaps a standard longshaft would do.

You would only then need an ex long tiller extension and gear lever extension.

It has occured to me that it may be cheaper (unless your engine is complely goosed) and certainly less work to have your engine repaired.

Edited April 30, 2020 by Mad Harold

[Alan de Enfield]

29 minutes ago, Mad Harold said:

It was a longshaft because of the distance from the trapezium mounting

 

Just for the OP's benefit the Trapezium is the outboard bracket which lowers (swings) down and locks in place when underway, swings up and locks in place with the engine out of the water when not in use

 

33 minutes ago, Mad Harold said:

has occured to me that it may be cheaper (unless your engine is complely goosed) and certainly less work to have your engine repaired.

 

Agreed.

[Mad Harold]

28 minutes ago, Alan de Enfield said:

 

Just for the OP's benefit the Trapezium is the outboard bracket which lowers (swings) down and locks in place when underway, swings up and locks in place with the engine out of the water when not in use

 

 

Agreed.

Thanks for that Alan.

I trained as a teacher many years ago and forgot what was drummed into me at that time.

"Don't assume that what is clear to you,is equally clear to everyone else".

[Onewheeler]

19 minutes ago, Mad Harold said:

Thanks for that Alan.

I trained as a teacher many years ago and forgot what was drummed into me at that time.

"Don't assume that what is clear to you,is equally clear to everyone else".

Perfectly obvious to anyone who's married to anyone of any gender.

[OldGoat]

An unsolicited note of caution -

If you're fitting an outboard make sure it's got some really effective anti theft device - 'cos ther are lots of nasty folks around.

Alternatively get a cheap Seagul OB - cos they're not so attractive to pinch. They're also quite good for canals as their propellors are pretty solid...

[ditchcrawler]

1 hour ago, OldGoat said:

An unsolicited note of caution -

If you're fitting an outboard make sure it's got some really effective anti theft device - 'cos ther are lots of nasty folks around.

Alternatively get a cheap Seagul OB - cos they're not so attractive to pinch. They're also quite good for canals as their propellors are pretty solid...

This is from the Norfolk Police https://www.norfolk.police.uk/sites/norfolk/files/outboard_engine_cover_poster.pdf