Very small inboard engine?

[Tranona]

Such things were relatively common 50+ years ago, usually with a Stuart Turner 1 1/2hp in an 8' clinker and a 4 or 5hp in a 10' Ken Latham in Poole built several for members of Parkstone and Royal Motor to get out to their moorings. Kept on running trots off the wooden piers. Worked with Ken converting our Seagulls into sort of saildrives to replace the STs but never really worked.

Today's equivalent would be an epoxy clinker stem dinghy of 10-12' with an ePropulsion electric pod drive Speak to Westaways Boats.

 

[AntarcticPilot]

If an air-cooled engine is ok, Briggs and Stratton do engines with horizontal shafts as well as vertical ones. In the 60s we had a Briggs and Stratton engine in our Trotter (a version of the Pandora).

I think these are they: Horizontal Shaft Engines | Briggs & Stratton Southeast Asia. But there's no guarantee they meet UK/EU emission regulations.

 

[Blue Seas]

My modified Sabb 8hp.

 

[William_H]

I think it all very well for OP to dream of an old small inboard engine or his tender but think he should leave it at the dream stage. Those engines were not so reliable as we might imagine often hard to start. I think the practical answer is a small out board.I recently bought a small Honda 2.3hp for the main boat. The big advantage is the air cooling so no water pump etc, one of the biggest sources of problems. For me the tender is always rowed but that is die to local circumstances. ol'will

 

[ashtead]

I suspect buying a small Honda brings a whole host of other problems -better if the OP can get there to buy a 2 stroke in Alderney or more interestingly in carribean -a 2stroke 9hp would set him going nicely up to the moorings

 

[Gixer]

Something a friend of mine did years ago was bought a smashed standup jetski, took the engine and impeller tube out and fitted to a small pram style dinghy. It was done for a bit of fun but actually worked really well and if you wanted it to, went like stink!!

 

[trapper guy]

Can you not swap a spare battery if that’s a regular concern?

i did say that if your batteries are flat, thats your lot, this includes spares.
lets face it, a spare battery would only hold a couple of hours at maximum.
my thinking primarily surrounds use of a dinghy as an emergency vessel, in case your boat is sinking sorta thing.

i wouldnt want to have to rely on a spare battery having held its charge, whereas a can full of fresh-ish fuel is dependable.

 

[dunedin]

i did say that if your batteries are flat, thats your lot, this includes spares.
lets face it, a spare battery would only hold a couple of hours at maximum.
my thinking primarily surrounds use of a dinghy as an emergency vessel, in case your boat is sinking sorta thing.

i wouldnt want to have to rely on a spare battery having held its charge, whereas a can full of fresh-ish fuel is dependable.

Wow that is completely different from the OPs requirement.
And for a sinking vessel:
- a liferaft and EPIRB would be much more effective in getting rescued than trying to motor a few miles mid ocean,
- Once a petrol can is empty it is gone. A good solar panel could keep a Torqeedo going for a short time every day indefinitely

 

[Stemar]

Here you go

 

[trapper guy]

Wow that is completely different from the OPs requirement.
And for a sinking vessel:
- a liferaft and EPIRB would be much more effective in getting rescued than trying to motor a few miles mid ocean,
- Once a petrol can is empty it is gone. A good solar panel could keep a Torqeedo going for a short time every day indefinitely

i understand you may feel personally attacked by my opinion.
but its just my opinion, batteries have proven themselves to be unreliable, in my own experience
plus a fuel can doesnt need to be plugged into a charger to counter the inevitable self discharge

 

[rotrax]

Is there such a thing as a very small petrol or maybe diesel (not electric) inboard engine, perhaps 7 HP, which could be fitted to an equally small traditional dinghy, about 10' x 5', for use as a tender? At the moment our tender is a BRIG Falcon 330 RIB with a 20HP outboard but we only use it for going ashore and after 9 years and over 50 different berths and anchorages we've never wanted to run it much above tickover due to speed limits. And neither me nor my wife have any desire to go fast anyway. Our main boat only does 7kts. We are slow fair-weather boaters. I'd much rather have a traditional boat as our tender, and I'm fed up with the complications of modern outboards. I'd be happier with an old fashioned simple little inboard engine. I might even go for a wood tender if I can find a tiny engine. Any ideas? I suspect I'm 50 years out of date here as with most things :-(

We have a Suzuki 4HP four stroke outboard, modified to 5 HP by the simple expedient of bending the stop plate to allow further throttle butterfly opening. That is all the twenty quid option throttle stop does-the 6HP is the same engine with a bigger carb.

It was supplied new with the boat in 2008. It is euro 2 spec. I have had no starting or running trouble in nine seasons of my ownership. I checked the impellor, changed it and keep the old one as a spare. Origonal spark plug too. I have just re painted the lower part of the leg as a few bits of black paint were missing. It looks like new again, and still runs like new.

A modern low power four stroke outboard with sensible fuel management is pretty foolproof, and cheap.

One of those would be my preffered replacement if I were in your situation. A 20HP is far too big.

 

[Aeolus]

Sounds like you are in the market for a Torqueedo or Remigo electric outboard .... I've had a lift ashore in a dinghy with with a Torqueedo, and was impressed.

I agree, also consider E-propulsion. Would almost certainly be cheaper than an inboard engine, pretty much maintenance-free, very very easy to operate and perfect for going slowly.

 

[rotrax]

have heard many positive opinions about the seagull engines, 'will troll all day on just a cupfull of petrol' being a memorable one

From diect experience of using a 40 plus on rivers and canals with a 16 foot open dinghy with four adults and a picnic basket and toolbox, that is total bolleux.

It was quite heavy on fuel. My current Suzuki four stroke however, is incredibly frugal. It runs almost two hours on its integral tank unless bashing into wind and chop. Careful trimming is, of course, essential for economy. Both engine trim and load in dinghy trim.

 

[Tranona]

imho, you cant keep a recharge for an electric motor in a spare tank, once your batteries are flat, thats it

How is that any different from an empty fuel tank? surely the issue is of range and the OP is only doing short runs ashore. An electric outboard on a smaller inflatable or RIB is a good choice.

 

[Tranona]

From diect experience of using a 40 plus on rivers and canals with a 16 foot open dinghy with four adults and a picnic basket and toolbox, that is total bolleux.

It was quite heavy on fuel. My current Suzuki four stroke however, is incredibly frugal. It runs almost two hours on its integral tank unless bashing into wind and chop. Careful trimming is, of course, essential for economy. Both engine trim and load in dinghy trim.

As an ex Seagull employee I was also taken aback by the comment. Seagulls were good for a lot of reasons in their day but fuel economy was not one of them. However most of them , particularly the 40 series were only run for short periods at a time so fuel consumption was not an issue. Likewise with Stuart Turners which drank fuel but only used part of it to produce power, the rest went out of the exhaust!

 

[Snowgoose-1]

Is there such a thing as a very small petrol or maybe diesel (not electric) inboard engine, perhaps 7 HP, which could be fitted to an equally small traditional dinghy, about 10' x 5', for use as a tender? At the moment our tender is a BRIG Falcon 330 RIB with a 20HP outboard but we only use it for going ashore and after 9 years and over 50 different berths and anchorages we've never wanted to run it much above tickover due to speed limits. And neither me nor my wife have any desire to go fast anyway. Our main boat only does 7kts. We are slow fair-weather boaters. I'd much rather have a traditional boat as our tender, and I'm fed up with the complications of modern outboards. I'd be happier with an old fashioned simple little inboard engine. I might even go for a wood tender if I can find a tiny engine. Any ideas? I suspect I'm 50 years out of date here as with most things :-(

How about trying rowing for a season as a fun thing to do.
Humanoids produce about 1.2hp . You could even badge your back "God 1.2hp." For me, small 4T were a game changer for tenders.

 

[LittleSister]

If an air-cooled engine is ok, Briggs and Stratton do engines with horizontal shafts as well as vertical ones. In the 60s we had a Briggs and Stratton engine in our Trotter (a version of the Pandora).

I looked at a Trotter with a view to purchase many years ago (in Exmouth?). That had a Briggs & Stratton engine. I'd assumed at the time it was a home 'PBO' style installation, but maybe they were fitted by the yard building the Trotters.

 

[TwoHooter]

Thanks everyone.

I should have said that although we don't go fast we do go longish distances up estuaries and rivers. For example Plymouth to Calstock, Bristol up the Avon, Southwold to Blythburgh, and some Irish rivers. Electric doesn't work because charging without shore power is a problem now we have reconfigured our big boat so we only need to run the generator 2 hours per day at anchor. Also I counted up our batteries recently, 72 battery-operated devices total in home and boat from tiny buttons up to 255Ah AGMs and whatever it is in the hybrid car, every sort of chemistry. Fed up with the things, don't want to add to the collection.

We already have a 3.5HP Honda 4 stroke air cooled outboard for our inflatable tender which is what we use if all we want is a ferry to the shore. Wouldn't want to drive that for 2 or 3 hours.

If a suitable engine does exist I would probably have a custom dinghy with a skeg to protect the prop.

I'm fed up with modern outboards because I have spent a lot of money on incompetent mechanics whose abikity seems to be limited to staring at laptop screens and fitting sundry new parts, with an attitude that they are doing me a favour even when the bruddy thing still doesnt work properly. Currently trying DIY repair of the failed Suzuki 20hp on the BRIG and hating every minute. Not how I want to spend my time.

I'll follow up some of the ideas here and if anything works I'll post again.

 

[trapper guy]

How about trying rowing for a season as a fun thing to do.
Humanoids produce about 1.2hp . You could even badge your back "God 1.2hp." For me, small 4T were a game changer for tenders.

i would question that figure for sure. can i produce as much power as 1.2 horses? that is highly doubtful, i would be happy if i could produce the work of half a horse.
hell, if i pulled a trap full of passengers 1/2 a mile i think that would be the end of me

 

[trapper guy]

Can you not swap a spare battery if that’s a regular concern?

its an energy density issue for me, batteries will not have the energy density of a gallon of petrol for many years to come, if ever. unlike an empty fuel tank, a battery cannot be recharged in under 3 minutes