ePropulsion Spirit 1 EVO hydrogenerator in YM

[lustyd]

Acceleration is of no consequence in a yacht tender, speed through the water when the revs have got up to max is. If you have a 15 minute trog out to the mooring, that is determined by the boats top speed, not whether it gats to maximum revs in 2 seconds or half a second. Once the petrol outboard is at max revs, a 3 hp motor will push it through the water faster than a 1 kW motor and hence shorten the time taken to get to the mooring - a real advantage. Who cares about the first 2 seconds of the trog?

But (you're still missing the point) if the prop on the petrol one can only put 1HP into the water because it's designed to avoid stalls at low speeds then it's completely moot, isn't it? If one motor can use all its power and the other can't then the ultimate power output of the unit is irrelevant, it's the in the water power that matters, and the ability to push the water backwards. There's more to speed than RPM when you're looking at prop design.

 

[Neeves]

Osculati make an attractive aluminium sliding outboard mount with 40cm travel. Wondering if this is enough? Probably not as the prop itself is 30cm.

You need to ensure that the bracket is strong enough (or you can make strong enough) to take the stresses that will be imposed if your yacht can achieve consistent 8-10 knot boat speeds - with the unit in re-gen mode. Its a big prop and it will generate a lot of drag. A further option would be to offer a smaller and easily interchangeable prop for higher boat speeds.

Jonathan

 

[KompetentKrew]

The WattnSea has been ocean tested and apart from a few issues, some of which WattnSea have suggested are caused by owner modification of which they did not approve, seem to be reliable - and does what is says on the box (at a price).

If I correctly recall previous threads on the Watt & Sea, there's a metal pin that may sheer under high loads. That or the mounting bracket.

The SailGen & DuoGen got a slightly higher score on Sailing Today's group test and the way they are dragged through the water makes more sense to me - they swivel, so would seem to be less load; the Watt & Sea exerts all its load on a single hinge point. However it is not clear to me that I could fit the DuoGen alongside my tender on davits.

I've not articulated myself quite as well as I liked in that comparison, but I think my point is clear enough.

 

[Neeves]

If I correctly recall previous threads on the Watt & Sea, there's a metal pin that may sheer under high loads. That or the mounting bracket.

The SailGen & DuoGen got a slightly higher score on Sailing Today's group test and the way they are dragged through the water makes more sense to me - they swivel, so would seem to be less load; the Watt & Sea exerts all its load on a single hinge point. However it is not clear to me that I could fit the DuoGen alongside my tender on davits.

I've not articulated myself quite as well as I liked in that comparison, but I think my point is clear enough.

My comments on the reliability of the WattnSea were based on the simple, totally subjective, analysis that if they survived the Vendee Globe then they should be good enough for us. Having said that one of the Imoca 60s did stop over on one VG at Sandy Bay, Auckland Island (nowhere near Auckland but deep in the Southern Ocean) - I recall to make some running repairs to the WattnSea unit. What is interesting of the ST test is a comparison of the length of competitive units, like the Duo gen, and or the depth (presumably why some are so long) they appear to be installed such that the propellor is well below water level.

Jonathan

 

[PeterWright]

Acceleration is of no consequence in a yacht tender, speed through the water when the revs have got up to max is. If you have a 15 minute trog out to the mooring, that is determined by the boats top speed, not whether it gats to maximum revs in 2 seconds or half a second. Once the petrol outboard is at max revs, a 3 hp motor will push it through the water faster than a 1 kW motor and hence shorten the time taken to get to the mooring - a real advantage. Who cares about the first 2 seconds of the trog?

But (you're still missing the point) if the prop on the petrol one can only put 1HP into the water because it's designed to avoid stalls at low speeds then it's completely moot, isn't it? If one motor can use all its power and the other can't then the ultimate power output of the unit is irrelevant, it's the in the water power that matters, and the ability to push the water backwards. There's more to speed than RPM when you're looking at prop design.

No outboard manufacture is daft enough to build a 3 hp engine then fit a prop which can only handle 1 hp, the props are matched to absrb the engine's fullnpower at the engine's peak power revs.

 

[lustyd]

No outboard manufacture is daft enough to build a 3 hp engine then fit a prop which can only handle 1 hp, the props are matched to absrb the engine's fullnpower at the engine's peak power revs.

Curious then that they supply a different prop on the yacht versions of outboards.

 

[dunedin]

Curious then that they supply a different prop on the yacht versions of outboards.

Because at full power a dinghy will be travelling faster than a yacht at full power, so needs different pitch.

So both built to handle the 3hp, but doing different jobs

 

[lustyd]

Because at full power a dinghy will be travelling faster than a yacht at full power, so needs different pitch.

So both built to handle the 3hp, but doing different jobs

My point was that they might be able to fit something to achieve higher top speed with a bigger load if there wasn’t the risk of a stall at low revs. Lots of variables which ultimately mean that the insistence that raw power be the same is nonsense and that’s why they use slightly woolly terms. I’m more than happy with their description and those on the thread who have experience seem happy too.

 

[nestawayboats]

First apologies for long delay in replying to queries on this thread. We are not as some appear to believe a marketing machine poised waiting for every possible opportunity to post on YBW. I just check in occasionally and chip in if I feel it might be relevant. I didn’t even know Google could be set up to alert me to relevant posts, as somebody suggests (I will probably look it up but if someone wants to give me a fast-track tip how…).

Re the Epropulsion EVO:

- main differences between this and the “standard” Spirit PLUS are that it has a choice of (removable instead of folding) tiller or remote control, and the much-discussed regenerative charging facility

- the screens on the EVO’s removable tiller or remote control show more data than the PLUS model, eg speed (possible because the EVO ones have GPS)

- the regen starts at 4 knots but only really makes a useful amount of power if you can sustain 6 knots plus

- the regen also causes drag (you can’t have something for nothing) so is not very useful on lighter boats (eg dayboats), where the drag is more significant relative to the power required to move the boat, and will slow you down (quite probably below 6 knots, at which point it’s not much use anyway).

- another issue touched on is mounting it for regen on the back of a yacht. As all yachts are different there is no standard solution but as others have mentioned it has to be low enough and strong enough

- I was previously given (and with apologies passed on) the wrong answer re whether the tiller has to be connected for regen to work… it does, electronically, but not necessarily attached (physically) in its usual position. You can have it connected via an extension cable, so you don’t need to space the whole motor a tiller’s length from the back of the boat. Not putting the tiller in the usual position may be more convenient in other ways too, as it can then be up in the cockpit rather than down near the waterline

- the regen output needs to go into the Epropulsion battery first (which can also be located off the outboard if you wish, again extension cable is available). It can then be used to recharge the Epropulsion battery itself, or, via another optional cable, as a 48V output. Converting 48V DC to 12V DC to charge your yacht’s batteries is relatively straightforward with off-the-shelf products.

The EVO’s regen feature is probably not as good as a dedicated water generator might be, particularly at lower speeds. Indeed, generally speaking I personally prefer standalone items that do one job well. But as the EVO outboard including its lithium battery costs less than some if not all of the dedicated water generator options, it may be of appeal to some owners. Once you have a mounting system sorted it’s making use of a piece of equipment (your dinghy outboard) that would otherwise be unused at sea.

Re 1kW electric outboards being “3hp equivalent” (or worse “equal”) argument:

- I would far prefer nobody (it wasn’t us) had ever come up with that but one of the manufacturers did 15 years ago and as a retailer we’re now stuck with it (or at least explaining it)!

- If let’s call them company A decides to call their 1kW motor equivalent to 3hp then it’s very difficult for Company B who later make a (in many ways) similar 1kW motor not to make the same claim. Some, many or even most customers (and indeed retailers) won’t read past the headlines. So now at least two manufacturers (and I think it’s actually 4) say their 1kW electric motors are equivalent to 3hp petrol ones, and we’re really stuck with it.

- we’ve never unless by accident said a 1kW outboard motor is equal to a 3hp petrol one. What we have said is that, for most people and how they use their boats, they achieve much the same thing, except as others state for pushing a lightly-loaded dinghy on the plane (the electric ones won't do this). I would even go so far to say that pushing a heavily loaded flubber around the harbour at 3-4 knots, a 1kW electric motor may be more effective than a 3hp petrol one (before we get into how pleasant and easy it is to use). Turning a relatively large propeller relatively slowly, which is what the electric motors do, is better in some situations than spinning a smaller propeller faster (petrol motors).

- someone else has already kindly quoted large chunks of our website, which go into more detail on this. But given that I’m forced into explaining a statement made and advertised extensively by manufacturers who supply us, I stand by use of the word “equivalent” (specifically not equal), further qualified with “for most users”

I’m not aware of any customers who’ve bought a 1kW electric outboard and would go back to their 2.5 to 3.5hp petrol motors. And for some their 1kW electric has replaced up to 6hp outboards without much effect on how they actually use their dinghies (because harbour speed limits and/or what’s socially acceptable going past other boats and/or 6hp still won’t usually get more than two people on the plane), whilst experiencing a vast improvement in usability. (But I am NOT saying a 1kW electric is equivalent to a 6hp petrol, before anyone leaps on that!)

Ian, Nestaway Boats Ltd

 

[TiggerToo]

I’m not aware of any customers who’ve bought a 1kW electric outboard and would go back to their 2.5 to 3.5hp petrol motors.

we certainly wont.

Thanks N-away for selling us a fantastic bit of kit which (so far) has performed impeccably.

 

[AntarcticPilot]

<SNIP>

- we’ve never unless by accident said a 1kW outboard motor is equal to a 3hp petrol one. What we have said is that, for most people and how they use their boats, they achieve much the same thing, except as others state for pushing a lightly-loaded dinghy on the plane (the electric ones won't do this). I would even go so far to say that pushing a heavily loaded flubber around the harbour at 3-4 knots, a 1kW electric motor may be more effective than a 3hp petrol one (before we get into how pleasant and easy it is to use). Turning a relatively large propeller relatively slowly, which is what the electric motors do, is better in some situations than spinning a smaller propeller faster (petrol motors).

<SNIP>

Ian, Nestaway Boats Ltd

It's noteworthy that Seagull adopted exactly the same approach before a lot of us were born! A large, slowly turning propeller is more effective for a displacement hull at low speed. And Seagull were just as creative about their HP ratings as electric outboard manufacturers!

 

[Travelling Westerly]

we certainly wont.

Thanks N-away for selling us a fantastic bit of kit which (so far) has performed impeccably.

Thanks from me as well Ian, most helpful as always.

If you are still on here, do you see any issue with leaving the outboard (not battery) mounted outside. I'm thinking it's obviously waterproof but what do you think about the plastic and UV?

Cheers

 

[nestawayboats]

Cornish Westerly. I think for longer term storage (eg when away from the boat) I'd put it inside the cabin or in a locker if I could, mainly for security. And as there isn't any oil or petrol to leak out, and it doesn't mind which way up it's stored, putting it inside somewhere is a lot easier!

If you do need to store it outside then I think some "yellowing" of the plastic is inevitable over time (as in years), but that's only cosmetic and if you have an Epropulsion EVO model (ie removable tiller) and are storing the battery inside then there's not a lot of exposed plastic left.

As an aside Torqeedo and Epropulsion seem to use very similar plastic - I was told it's something to do with heat resistance and rules around lithium batteries. The Torqeedo Travel series (ie old 503, 1003 and current 603, 1103) has been around for 12 years now, without any UV issues (other than yellowing) that I'm aware of. We've seen a few ratty old uncared for examples, but none with "structural" UV damage/weakening so far as I can tell.

Ian, Nestaway Boats Ltd

 

[sailingmartin]

Another thank you to Ian at Nestaway. My new Torqeedo (1103) which replaced an earlier model I had for 10 years, is quiet, efficient and strong enough to push along my Portabote tender at an acceptable speed, at least for me. I won’t be going back to a previous Suzuki 2.5, although that was also a great little motor.

 

[TiggerToo]

Thanks from me as well Ian, most helpful as always.

If you are still on here, do you see any issue with leaving the outboard (not battery) mounted outside. I'm thinking it's obviously waterproof but what do you think about the plastic and UV?

Cheers

I keep it "Indoors" (i.e. down below/in the locker) when not in use. That is because a) we have space and b) prefer not to test its sensitivity to UV myself (;-)). This is for "long term storage". Obviously, it stays on the pushpit when we are cruising / pottering

 

[TiggerToo]

And as there isn't any oil or petrol to leak out, and it doesn't mind which way up it's stored, putting it inside somewhere is a lot easier!

this a real advantage from so many points of view. Far outweighing any "non-plane" issues (I have never bothered planing with my suzuki/honda either: the tender was always just a means of transport rather than show-off)

 

[mjcoon]

this a real advantage from so many points of view. Far outweighing any "non-plane" issues (I have never bothered planing with my suzuki/honda either: the tender was always just a means of transport rather than show-off)

I must admit I thought that planing was where you got the best mpg as well as showing off. But maybe that is more derived from planing sailing dinghies than tenders, where fuel is not actually measured!

 

[Kelpie]

I must admit I thought that planing was where you got the best mpg as well as showing off. But maybe that is more derived from planing sailing dinghies than tenders, where fuel is not actually measured!

If you just need to go a quarter mile to your mooring then planing doesn't really matter.
Some anchorages leave you a long way from shops etc and the difference to daily life from 4 Vs 15kt is substantial. Also planing, I am told, is drier.

 

[TiggerToo]

If you just need to go a quarter mile to your mooring then planing doesn't really matter.
Some anchorages leave you a long way from shops etc and the difference to daily life from 4 Vs 15kt is substantial. Also planing, I am told, is drier.

maybe it is. I was just writing that we never planed anyway, even with a petrol O/B. It is just something we don't do, and never have done.

 

[dunedin]

If you just need to go a quarter mile to your mooring then planing doesn't really matter.
Some anchorages leave you a long way from shops etc and the difference to daily life from 4 Vs 15kt is substantial. Also planing, I am told, is drier.

Yes, it does depend a lot where you are cruising and how often using the dinghy. Going a mile each way to and from the shops or only water supply, the top speed does make a material difference. Pottering ashore 300m to go to the pub, less so.