Emergency Outboard Get-You-Home Question.

[peterb26]

Does anyone have any ideas would be the minimum size outboard that could be used as an "emergency get you home" - ie something that would drive at perhaps just 3-4 knots as tide is not a problem where I am based.

The boat is 28 feet long (sorry 8.4 metres), deep V but planing hull, wheelhouse fishing boat design (no flybridge), draft 2ft 6inches (.8 metres) and displacement about 2 tonnes.

I had it in my mind that even a 5hp would push it along at this speed - but I wondered if anyone else could help or might have experience. I do stress that I only want to be able to plod at 3-4 kts.

Many thanks in advance to anyone who can assist.

 

[nyx2k]

my 2hp aux pushes my 17ft boat at 4knts on full throttle. so hp sounds ok for a real emergency

 

[landlockedpirate]

I tried a 5HP on a 27ft, 2000kg Bayliner. It just managed 3kts over ground with no wind or tide. I think I would go for an 8HP as a minimum.

Discussion the forum seems to point to the Tohatsu 9.8hp as a good compromise weight/power.

Mark

 

[peterb26]

Thanks for that Mark.

The other thing is that if I run the O/B at WOT then its going to drink fuel like its going out of fashion and I dont want to cart a petrol bowser behind me.......

 

[drewstwos]

Hi
some time ago i wrote a post about this very subject. My bopat is almost exactly the same as yours... ie 26 ft by 10ft by 3 ft ...I tried the OB which is a 15 hp Yam 4 stroke both on its own and in conjunction with the main diesl.. in my case a 50 hp perkins. Being an SD hull the design speed is about 6.5 kts.. which she doe quite happily all day on a gallon an hour.. with the OB it added an extra 2.5 kts ut we were then coming up a against the bow wave. OK..... on it's own it s gave us about 3 kts. so it would get us home in time. I always carry about 4 hours woth of petrol.. just in case. Almost needed it when we caught a rope round the prop but the cutter neatly severed it with no probs. a pot marker... unseen so my advice FWIW is don't be misled into getting a small OB... mine is just enough at 15 hp. I would feel happier with a 25,, but this one came with the boat.
MIne hangs on a special swim platform bradket...think i posted some pics.. but if you need any more infor PM me.
hope this helps

Drew.

 

[aquaholic]

Easy to go down the road of getting a 5-8hp as they will move the boat, however i doubt it will push you far aagainst a wind and tide. I would go for a min of 10hp, but think a 15+ would be much better. If like me you have one of those standard US metal brackets that are bolted onto the swim platform then they are rated to a max of 25hp

 

[peterb26]

Neil - any ideas where you get those swim-platform brackets please?

 

[galeus]

Hi I've got a 26ft disp. boat with a back uo 10hp johnson which will push our boat at up to 5 knts.We carry about 4 gallons of petrol normally but if we think we may get somewhere remote I increase that with extra 1 gall.containers temporaly.

 

[pelicanpete]

Just as important as getting the appropriate HP for the size of your boat is the right gearing of the o/b and prop. type. I would seek advice from the outboard dealer and ask what is the correct gearing for the use you intend, the length of the leg and the fitting of a high-thrust propeller.

 

[aquaholic]

This is the type of Bracket I have and it is fixed via 6 x stainless bolts, I have added a piece of 3/4 ply which was soaked in resin to give additional strength under the platform.
Not sure of a UK supplier, but they retail at around $180/£90 in the us, not really too much to them and you maybe able to get someone to make one for you in ally ?? if you need any more info or pictures of mine just let me know

P.S. I was wrong about the HP rating its 20 not 25 /forums/images/graemlins/blush.gif

 

[davierobb]

I have a 26' bilge keel snappy and use 4 hp Johnson as a get me home and to push the dinghy along at a very respectable speed. It pushes the snappy along at around 4 knots. The engine does exactly what I want and I’m well aware of its limitations when subjected to high winds and tides.

I did not employ a team of marine engineers to spec this engine and prop as suggested in some replies. The engine is just a get me home under normal conditions, if I wanted an engine to get me home under all conditions then I guess I would need to fit a second inboard diesel. I’m sure this would get me instant membership of the YBW specify it high and THINK your safe club. /forums/images/graemlins/smile.gif

 

[aquaholic]

Lets just hope you dont break down but if you do its under "normal conditions" /forums/images/graemlins/tongue.gif

 

[davierobb]

The bottom line is you cant cover all bases but so far my strategy has not led to any third parties being involved in my safe arrival at chosen destination. Touching a large piece of wood as I type this. /forums/images/graemlins/smile.gif

 

[RogerRat]

Have a look at the back of 'Got One Too' I think it's a Jenneau 925 with a flybridge. I'm sure you know the boat it's in sparkes as you walk round, two along from Flower Power.

'Phil' runs a 6 Hp 4-stroke as an auxilliary on a swim platform bracket and can get hull speed ok. It also doubles up as a tender motor.

I wouldn't have thought you should go smaller than that as you don't want to have to thrash it to death.

 

[peterb26]

Thanks Roger.

 

[victoraspey]

Interested in this emergency outboard topic. What you think hull speed is on 925??. On my 30 ft cat we tried a 2 hp electric auxiliary and did nearly 6 knots and also tried a single 9.9 hp and did 7 knots. 2x 9.9hp gave nearly 9 knots. Easily driven hulls..........

 

[duncan]

tohatsu 9.8 2s as already recomended - you will simply be limited in range by weather and the fuel you can carry.

given these limitations, and sods law, you will need it most when 100miles downwind of a safe haven - so you might as well carry a good radio and a sea anchor plus lots of provisions!

you have a stub keel on the starfisher - maybe a staysail rig would be better overall?

on balance whilst I carry an OB and tender I don't expect the OB to shift the boat more than a few miles - in which case I can simply anchor and move with a favourable tide up and down the channel. If it's that much of an issue I will leave the boat and head in in the dingy which will now have a huge range relative trying to shift the whole boat. Appreciate you don't have this option without a lot of anchor line!!!

 

[DaCostaGreene]

I expect my auxilliary to perform very nicely. In fact I had a week at sea ploughing into some pretty harsh weather with a pair of 9hp.

 

[duncan]

[ QUOTE ]
I expect my auxilliary to perform very nicely. In fact I had a week at sea ploughing into some pretty harsh weather with a pair of 9hp.

[/ QUOTE ]

they're not auxillaries they're your cocktail mixers!

/forums/images/graemlins/laugh.gif

 

[victoraspey]

yes - the cocktail mixers are our emergency-emergency form of propulsion. They can provide 3 knots but lousy in a headwind.