Emergency Outboard

[Simon391088]

Hi,

Is it possible to mount an outboard on the rails at the back of a sailing boat and lower it into the water if the main engine fails?

Is there a special bracket for this?

Presumably this must be a common setup, however the outboards I have seen all look like they are for dinghys rather than a backup engine.

Thanks
Simon

 

[mainsail1]

How big a boat?

 

[Mistroma]

Yes it is possible and you can get special brackets. One design is spring loaded to take the weight and the bracket is held vertical throughout movement up and down. Another type slides up and down in rails. I'm certain that there will be other designs. You usually need a long shaft outboard to keep the prop. submerged.

Unfortunately, the prop. moves up and down a lot when moving through waves and the movement becomes greater as boat length increases. Unless your boat is small the prop. will spend a lot of time out of the water unless you are in calm conditions.

If waves move the bows up and down by only 2.5 degrees in each direction, the stern on a 20' boat would move about 1' up and down. However, the movement would be 2' for a 40' boat. Figures are very rough but give an idea of amount of movement. It is even worse as you still need to allow for the effect of differing wave lengths. The prop. will be well clear of the water if a trough passes the stern when the bows have dipped down.

 

[Simon391088]

Hi,
For a 35ft boat. It seems like a good idea!
S

 

[mainsail1]

This may well be "a first" on a 35ft sailing boat. Usually the main auxiliary engine is very reliable if serviced on a regular basis. And you still have sails to use.
Another option is to use a dinghy with small outboard tied fore and aft to the hull side near the stern. Works well in emergency.

 

[Tranona]

Hi,
For a 35ft boat. It seems like a good idea!
S

Complete waste of time. A boat that size should have sails and a reliable diesel so why would you want to hang an outboard on the back? You would need at least 20 hp to make any progress in other than a flat calm and that would need a crane to lift it on and off. Plus it would have to be mounted so low down on the transom to get the prop in the water that you would need remote controls to operate it and an electric starter to get it going - and a remote petrol tank to feed it!

So don't waste time thinking about it, let alone money trying to do it. Just make sure your diesel is reliable.

 

[TQA]

If you have a good dink and OB a hip tow works surprisingly well and keeps the prop in the water.

In flat water and light winds even a 2 hp will push a typical 35 ft boat at 3/4 knots.

However it won't stop it in a hurry. [ Ask me how I know this.]

 

[armchairsailor]

If you have a sugar scoop, you can lash the dink to it and push from the back too. There was an article about this in a yachting mag I read couple of years ago.

 

[Simon391088]

Thanks for replies. I didn't realise it would be so problematic.
I had a power boat until last year and on that, one of the properly maintained engines suddenly wrecked itself during a journey. On that it was ok as we got home on the other engine. However it opened my eyes to the fact that any engine can fail at any time.

I've also seen a lot of sail boats having to be towed into their berths over the years, for example with ropes around the props.
On the face of it, an outboard at the back seems like an obvious backup - especially since it's only likely to be used close to the berth to get back in again as sails could be used up until that point. It would be a lot easier than trying to get back into a berth with a dinghy tied to the side.
I can see though that control of an outboard half lowered off the back might be a bit difficult!

 

[James_Calvert]

The problem with the outboard prop coming out of the water is one thing...
The powerhead being submerged as the stern pitches down again is another!

 

[mainsail1]

I think engine failure is far less likely than you may think. If the engine was to fail it would be normal practice to sail to the harbour/marina and call them on vhf to ask for a tow in, which usually does not incur a charge from my experience over the years. If you are competent with sails you can sometimes sail onto a hammerhead without help. Don't forget your anchor as a last resort and if you cannot get a tow then find somewhere to anchor.
In fifty years of sailing my engine has failed once and we sailed to our destination and asked the marina for a tow into the berth.
Oh, I forgot, on another occasion, my propellor fell off and we sailed into the marina and berthed on a hammerhead without assistance.
Oh, on a third occasion we could not get a lobster pot line off our propellor and, again, sailed into the harbour and alongside an easy pontoon.

 

[jdc]

I've certainly experimented with my 3.3HP outboard on the back on my dinghy, lashed alongside my 42', 15 tonne boat. It works fine. Easily enough way to get into a berth. The idea that 'forget it in anything but a flat calm' is missing the point: in anything but a flat calm I can sail: it is precisely a flat calm that this emergency back-up is for.

The other thing one can do is row! I find I can only make 0.6 knots when rowing flat out, but it's better thah nothing. During a 3-peaks race I rowed for an hour in the sound of Jura to get into water shallow enough to anchor. But we made it!

 

[doug748]

Thanks for replies. I didn't realise it would be so problematic.
I had a power boat until last year and on that, one of the properly maintained engines suddenly wrecked itself during a journey. On that it was ok as we got home on the other engine. However it opened my eyes to the fact that any engine can fail at any time.

I've also seen a lot of sail boats having to be towed into their berths over the years, for example with ropes around the props.
On the face of it, an outboard at the back seems like an obvious backup - especially since it's only likely to be used close to the berth to get back in again as sails could be used up until that point. It would be a lot easier than trying to get back into a berth with a dinghy tied to the side.
I can see though that control of an outboard half lowered off the back might be a bit difficult!

You are fine, the outboard on the back would work ok as you describe. These brackets are ugly though and the larger engine that you might envisage would be a PIA to have around the boat.

However I think you have to embrace a different Zen when you are in a sailing boat.

Sailors have an instinctive suspicion that the engine is going to fail and it does not faze him if it does. Pushing a power boat in anything above Force 1 would be a problem, normal sized sailing boats can be moved very well, you see marina blokes shifting boats like that all the time.

Your experience and instincts are in a slightly different tradition. I mean this in the best possible spirit - but maybe you see a boat being towed and instinctively think there is drama, there is none, it's routine. Without twin engines it is sometimes impossible to get into and out of marina berths without assistance. Two years ago I was on a marina arm when six were assisted out of a difficult corner.

So by all means fit the bracket but a dinghy lashed alongside will work better in almost all circumstances and a small outboard will do the job - slowly and with the use of guile - it's that different Zen again.
Good luck with the new boat by the way.

 

[jac]

I think the position with a sailing boat though is different to the Mobo scenario you mention.

You can sail back and even if your berth is inaccessible under sail, there will be somewhere nearby that you can moor under sail whilst you sort yourself out. Wait till slack water, wind to drop and a tow with a dink is straight forward.

 

[rogerthebodger]

Hi,

Is it possible to mount an outboard on the rails at the back of a sailing boat and lower it into the water if the main engine fails?

Is there a special bracket for this?

Presumably this must be a common setup, however the outboards I have seen all look like they are for dinghys rather than a backup engine.

Thanks
Simon

Here is a pic of my arrangement. I have a stainless steel outboard bracket that will fit in slides mounted on my transum. The outboard is normally stored on corresponding sides on the outside if the pushpit and is lowered in place from my solar panel goal posts that can also loft my dingy like davits.

I currently have a long shaft 20 HP outboard but I could fit a higher power if i need to.

I did have a 15hp short shaft from my dingy. this would push my boat slowly in flat water but in any swell the prop would come out of the water, that why I now have a long shaft.

My boat is big 50ft 24 tons so the current outboard will not push the boat fast but its only intended for used when there is no wind and in emergency situations.