Hi,

I am new to this forum, please be kind I am looking for some advise.

I have a 24ft Motor Sailer, 1,650kg (displacement) with an 8hp Diesel Engine built in (shaft drive). I am looking at getting an auxiliary outboard engine as a backup and had a look at the epropulsion spirit 1.0 plus outboard motor with 3hp.

I know it does not have much hp but I was wondering if anyone had any experience? The only info I came across was this YouTube video (Can an electric outboard survive offshore? Testing the ePropulsion Spirit 1.0 Evo - Ep145 - TSF, The Sailing Frenchman). But this is obviously a very different light weight boat.
I also had a look at the charts in this article and the obvious recommended size engine is 8hp improvesailing.com/guides/how-to-calculate-outboard-motor-size-for-sailboats.

Any thoughts? :) I do like the idea of going with an electric outboard motor and the epropulsion spirit 1.0 plus would still be in my price range.

Thank you everyone in advance for sharing your experience.

cheers,

Hi Yamaha,
Man, that's a little propeller (11"x5.8") for 1,650kgs.
It doesn't look like you could hook it up to your house battery/s either as it's a 40VDC battery.
Get a big alternator for your diesel and an inverter, the charger is a 240VAC in, 46VDC out.
Personally....ugh. I don't like it.
But each to their own!
Cheers,
SB

Hi Yamy. Put the effort and money into ensuring your engine is reliable. Does it have a hand crank? If so get proficient at starting by hand. I have a YSE 8 YANMAR that l can hand start in 5 degrees. Your engine backup atr your sails. Practice , practice, practice.
Gary

@garymalmgren thanks. Same YSE8 engine hear but it needs a lot of work. I had to fix the starter, new brushes and cleaned out a lot of grease built up. Starter is working now but engine still doesn't start and the alternator also doesn't seem to charge the battery anymore and a lot of other little things. I also tried to hand crank start the engine but still not starting. Now checking fuel injectors and checking the diodes of the rectifier. I just thought it would be nice to have an easy option with an electric outboard as an auxiliary. Still a newbie to sailing so wanna make sure I have a backup.

HI,

I'm currently going through the same kind of thought-process, but with a different goal in mind, which is to mount a retractable electric motor on a 20ft trailer-sailer (a Cygnet 20). I am still not sure if it would work (for a reasonable price). I am currently thinking of the ePropulsion 1.0 Spirit outboard or Pod. In my case, the alternative motor would be a 6HP Tohatsu outboard mounted on the transom. (So why have an electric motor at all, you may ask? It is a good question, and the answer is about convenience and pushing the boat in and out of marinas for day-sails. Like I mentioned, it might not prove worth it, but I like grappling with the engineering challenge to see if it could work). One advantage of these electric motors is that they are light and are relatively easy to mount and demount.

My initial reaction to your proposal is that a 1.0kW motor is under-powered for your boat, which is larger boat than mine (mine would be 20ft, 900kg). It would probably only be good enough for pushing you around the marina at, say, 2 to 3 knots, which is barely enough to make headway against any kind of weather. I don't expect to get more than about 5 knots, and that would only be in sheltered water, and only for short periods, say less than a few hours. The range of electric motors is limited by the size of the battery. Large batteries can get very expensive. By contrast, you can easily and cheaply extend the range of a diesel by strapping extra jerry-cans to the deck to allow for several days of steaming.

Question: What do you think you need the backup motor for? If you are thinking of getting off a lee shore in rough seas with a broken engine, the ePropulsion 1.0 will not do it. If you are thinking about saving face when getting into a marina, I suggest a subscription to Marine Rescue will be more reliable and much cheaper (so will hitching a tow, if you can get one from passing traffic). If you are thinking about steaming long-distance, invest in improving the reliability of your diesel, per the suggestions of other posters here.

If you have a dingy with a motor, tie the dingy to the boat and use the dingy motor to push it around in the marina at 2 to 3 knots. This is how Kevin Boothby does it on his YouTube channel How To Sail Oceans, and he does it because he does not have a motor of any description in his boat. Which brings this around to the question; if Kevin can sail up and down the east coast of the US with no motor at all, why do you think you need a backup? Does your motor-sailer have enough in its sails to get you where you want to go without an engine?

@Achernar Thank you for your post. The main use of the electric motor would be to get in and out of the marina (trolling). Last time I got into the marina the Diesel Engine wouldn't start back up. So it would be the backup for the marina mainly.

Hi
Just joined as have installed electric trolling motor in 25ft Contessa , for the same purpose - get off the mooring . Only need to have steerage way to manoevre out of tight mooring field into the open bay . Got short 24in shaft 54lb Watersnake to go in outboard well,but needed adjustment as motor catching back of rudder . Running off 110 Ah battery,with 50W solar panel . Not clever with electrics,but people at Jaycar,very helpful/knowledgeable .
Success - Have steerage way,but bigger 70lb Brushless Watersnake would be better,but $700,as opposed to $250 . Only 8kg kg + no fuel !!
Had 6hp short shaft Johnson -ideal but 28kg,and dropped it into cabin when removing . Previous owner left motor down, in the well ,locked and immersed = transmission disintegrated .
Just waiting for Stihl to have Battery Outboard - ? Convert a Chainsaw ?

I have tried, but not succeeded satisfactorily, to find a relationship between thrust (in pounds, or more strictly, pounds-force) and HP. The fundamental reason, I suspect, is that trolling motors are designed to keep your boat stationary or at steerage-speed, but propulsion motors are designed to move them. The complexity is that the thrust or force (which is what the trolling motors quote in pounds, or pound-force) increases exponentially with speed. So, before you ask what thrust you need to drive a 24 foot boat, you need to know what speed. 5 or 6 knots seems a good benchmark for most small to medium-sized sailing yachts. Then you go down the rabbit-hole of how you measure HP, and the relationships and conversions become less and less clear. And, add in a factor for over-optimism in the sales literature.

Here are some of my estimates and results-of-internet-searches (and these depend on a lot of inferences and assumptions) ...

40 lb (pound-force) electric outboard motor = 0.4HP = 320W or 0.32kW = 3.5 knots for a Careel 18 (owner's experience)
55 lb (pound-force) electric outboard motor = 0.5HP = 380W or 0.38kW = 3.0 knots for a Cygnet 20 (owner's experience)
122 lb (pound-force) electric outboard motor = 1.8HP = 1300W or 1.3kW = 4.7 knots on an 18ft (?) fishing boat (from YouTube)
260 (???) lb (pound-force) ePropulsion 3.0 = 6.0 HP (claimed by manufacturer) = 3000W or 3.0kW = 7.6 knots on something (These numbers don't add up, note that 1HP = 745.7W / 0.75KW)

In this context, PLanter4's experience, of getting steerage (1 to 2 knots?) with a 54lb trolling motor on a 24ft keelboat, makes sense.

Although the ePropulsion 3.0 (outboard or pod drive) looks tempting in terms of power, it needs a step-change in the electrical infrastructure and wiring on your boat to get to a 48V supply. You could use the OB with the battery, but the battery adds enough weight to the OB to make it as heavy as a petrol OB, see ecoboats.com.au/products/electric-motors/e-propulsion-electric-outboard-motors/navy-3-0-6-0-outboards/

Might be best to look at electric conversions on conventional outboards. Retain the outboard less the powerhead They are available commercially locally but are very expensive. I have a couple of dead Evenrude 6hp outboards I might have a play with later.

@Achernar awesome thank you. this makes a lot of sense :)

I use a 1kw epropulsion outboard on a Farr 727 it provides about 4.8knots top speed - for me, its fine for what i use it for - in & out of floating pen. It is restricted when there is significant head wind or the bottom is not clean. I doubt it would be very effective on a 24ft motor sailer.

Only just steerage way with 54lb on 25ft Contessa . Took her out today,off the mooring by watersnake,100m into the open bay,but zero breeze so tried to get back on electric power alone . Would be better with sweeps/oars,but all gets a bit complicated . Am on the right track,just need more grunt,but wary of cost + size/weight of battery . !05AH Deep cycle 30kg - more than 6hp Johnson .
Therefore,one way off the mooring,but sail back - not an option if penned !

Search this thread, lots of great info

Select to expand quote

PLanter4 said..
Only just steerage way with 54lb on 25ft Contessa . Took her out today,off the mooring by watersnake,100m into the open bay,but zero breeze so tried to get back on electric power alone . Would be better with sweeps/oars,but all gets a bit complicated . Am on the right track,just need more grunt,but wary of cost + size/weight of battery . !05AH Deep cycle 30kg - more than 6hp Johnson .
Therefore,one way off the mooring,but sail back - not an option if penned !

Have a look at the battery packs [lithium] that electric push bikes use. Work out what voltage you need and construct a battery pack to suit. Plenty of Youtube videos on the subject.

www.ebay.com.au/itm/195540211564?hash=item2d871ad76c:g:zNoAAOSwd6xjS1KQ&amdata=enc%3AAQAHAAAA8NWmuIswLmn5kjpF9NUnoUOGIS0iBBSOlagAQNggTBr0HrPprLQG%2Brmo3FXirUeSAslTn2Me4WtIQWjFA9PWNXo1PwFSFRqqKtmVPWYxUBjU3wm3f57qRXT07lrOyzTYdQcked0qbAZ1foZ%2BR%2B5PGSLL4%2FpUIolnA3RCV69TdZQNysKQ9FEwIVNROKy1uqy2aAMyKNFa%2Bk%2Bq4EIzmh%2BcPGHnhnZwR5Nnv2mUcJuXxQuUmfwLRvZsEwShS6UyU4NSd09ng9FVtD%2FDCa03yaNfeiTIgFdaBoH%2Fj7OtQsgUN%2FrmtOrbPuLqX1pDvE8d5IZ6Cg%3D%3D%7Ctkp%3ABk9SR-j8zrjfYQ

The pushbikes that will do 120kph will generally be 48 volts or more. A 48 volt motor on a 6hp Johnson outboard is going to perform as good as a normal 6hp outboard. This is a bike conversion kit on Aliexpress. I'm in NZ at the moment so ignore the prices.
www.aliexpress.com/item/4000332155133.html?spm=a2g0o.productlist.main.115.392461cfHlBbpX&algo_pvid=70fba1f4-0475-41d6-814d-5bcccfdc2d7d&algo_exp_id=70fba1f4-0475-41d6-814d-5bcccfdc2d7d-57&pdp_ext_f=%7B%22sku_id%22%3A%2212000018592909688%22%7D&pdp_npi=3%40dis%21NZD%21254.75%21203.8%21%21%21%21%21%40211bda9b16792580245522557d078a%2112000018592909688%21sea%21NZ%21753417160&curPageLogUid=BuFylxKsZiWx