Reply
 
Thread Tools Search this Thread
 
Old 07 October 2010, 15:53   #11
RIBnet admin team
 
willk's Avatar
 
Country: Ireland
Make: Redbay Boats
Length: 9m +
Engine: 370hp
Join Date: Feb 2008
Posts: 12,924
RIBase
That sounds like an all round Result, especially as you're probably breaking the speed limit at that
__________________

__________________
willk is offline   Reply With Quote
Old 29 November 2011, 14:14   #12
Member
 
Country: UK - England
Length: 3m +
Join Date: Nov 2011
Posts: 10
Hi, I'm a newbie on here, and I have been googling 'electric outboards' for a couple of days...

I am close to buying a 10-foot Porta-Bote (because I will be able to store it on top of my wardrobe!), and I plan to use it on the Grand Union Canal

But I can't decide how to power it...

A 2-3hp outboard would seem an obvious choice, but I am not so sure - the Porta-Bote is marketed as a planing hull, which is irrelevant in a 4mph speed limit. Also, small outboards are designed to run at around 5000rpm, which is also irrelevnt in a 4mph speed limit

IMHO, the Porta-Bote is less ugly in displacement mode, and a heavy battery, stowed up-front, would help to maintain a level fore-and-aft trim. But I would soon run out of juice - I would plan to be away for a couple of days at a time, visiting friends and generally exploring

Has anybody ever tried running an electric outboard with an onboard 'suitcase' generator? Would such a system run all weekend on a single 'tank' of petrol? Would it be possible to run the outboard directly from the 12v output of the generator, or would it be essential to run the power through the battery at all times?

Rookie
__________________

__________________
Rookie is offline   Reply With Quote
Old 29 November 2011, 15:00   #13
Member
 
Leapy's Avatar
 
Country: UK - England
Town: Sheepy Parva
Boat name: Sadly Sold
Length: no boat
Join Date: Sep 2008
Posts: 1,728
Check that the prop speed of an electric is fast enough/man enough to act as a weedcutter if you may venture on the less popular routes during the growing season, such as the Ashby in May to August. My experience of very small outboards on canals is that the prop quickly chokes if it encounters below the surface weed.

To say nothing of shopping trollies on the BCN ;-) or any urban canal for that matter :-)
__________________
Leapy is offline   Reply With Quote
Old 29 November 2011, 15:29   #14
Member
 
Country: UK - England
Length: 3m +
Join Date: Nov 2011
Posts: 10
Quote:
Originally Posted by Leapy View Post
Check that the prop speed of an electric is fast enough/man enough to act as a weedcutter if you may venture on the less popular routes during the growing season, such as the Ashby in May to August. My experience of very small outboards on canals is that the prop quickly chokes if it encounters below the surface weed.

To say nothing of shopping trollies on the BCN ;-) or any urban canal for that matter :-)
Hi Leapy, thanks for the reply

One of the things that I have discovered in the last couple of days googling is that electric outboard makers seem to be aware of the 'weed-cutting' issue, whereas petrolheads employ all sorts of complicated theorems about propellor pitch and diameter, versus engine speed etc, which surely don't need to trouble an aged hippy like me?

Cheers, Rookie
__________________
Rookie is offline   Reply With Quote
Old 29 November 2011, 16:00   #15
Member
 
SIBer's Avatar
 
Country: UK - England
Town: South Yorkshire
Boat name: Sold it !
Length: 3m +
Engine: Totallyhotsue 9.8 2S
Join Date: Sep 2011
Posts: 258
Quote:
Originally Posted by Rookie View Post



Has anybody ever tried running an electric outboard with an onboard 'suitcase' generator? Would such a system run all weekend on a single 'tank' of petrol? Would it be possible to run the outboard directly from the 12v output of the generator, or would it be essential to run the power through the battery at all times?

Rookie
My suitcase genny puts out 8 amps at 12v so not enough for an electric motor. Plus my suitcase weighs 18kg so add in the weight of a leisure battery at 25kg and you have an outfit as heavy as noisy as an outboard.
__________________
SIBer is offline   Reply With Quote
Old 29 November 2011, 16:33   #16
Member
 
Country: UK - England
Length: 3m +
Join Date: Nov 2011
Posts: 10
Quote:
Originally Posted by SIBer View Post
My suitcase genny puts out 8 amps at 12v so not enough for an electric motor. Plus my suitcase weighs 18kg so add in the weight of a leisure battery at 25kg and you have an outfit as heavy as noisy as an outboard.
The weight is not really an issue - I would be able to use the genny and the battery to adjust the trim of the boat

Noise might be significant, but the noise of a generator is different from the noise of a small outboard, and some people might think it is less annoying... I need to do some more research

The cost of a genny + battery + electric outboard will be high, but I am tempted to believe that electric outboards are more suited than petrol to low-speed, low-stress situations like canals, if only the power supply could be extended beyond an hour or three

I remain open to persuasion!

Rookie

ps - the low power output of the genny would be mitigated by the fact that the battery would be charged during each stop period, such as locks and pubs etc...
__________________
Rookie is offline   Reply With Quote
Old 29 November 2011, 17:26   #17
Member
 
SIBer's Avatar
 
Country: UK - England
Town: South Yorkshire
Boat name: Sold it !
Length: 3m +
Engine: Totallyhotsue 9.8 2S
Join Date: Sep 2011
Posts: 258
I have a Honda Eu20i - Its the dogs but not as "silent" as advertised.

For more power have a mains voltage charger. If you want the best look at the CTEK ones. I've 10 year old leisure batteries still going strong that have been maintained on a CTEK.
The top of the range is the 25amp model but mine is the 7 amp at 100.

For the 600 a Honda eu10i would cost you could get a decent flexible solar panel for a lot less.

Cheap generators aren't worth it. I had a Chinese knock off and after a year it wouldn't start so I bought the Honda I should have bought in the first place.

Keep up the google fu and good luck.

I've done some canal barging in my time and the pubs are great as no drink drive laws on the waterways but don't expect your motor and generator to still be on an inflatable after an afternoon pub session!
__________________
SIBer is offline   Reply With Quote
Old 29 November 2011, 18:30   #18
Member
 
Country: UK - England
Town: NW Surrey
Boat name: Lady Helen
Make: Avon
Length: 3m +
Engine: Out Petrol 3.5 & 15
Join Date: Aug 2011
Posts: 222
Quote:
Originally Posted by Rookie View Post

ps - the low power output of the genny would be mitigated by the fact that the battery would be charged during each stop period, such as locks and pubs etc...
In a lock you would need to stop the genny, presumably because of the build up of fumes. While waiting to enter you would still be able to run it.
__________________
EnglishLes is offline   Reply With Quote
Old 29 November 2011, 18:51   #19
RIBnet admin team
 
Poly's Avatar
 
Country: UK - Scotland
Boat name: imposter
Make: FunYak
Length: 3m +
Engine: 2 stroke YAM 20 HP
MMSI: 235089819
Join Date: Sep 2005
Posts: 10,112
If you want more of a genny sound than an outboard then look at a Honda aircooled outboard. Its causes a different variety of deafness!

A petrol outboard will give out maximum power at 5000 rpm, but it won't do any harm to run it at less than that with a sensible choice of prop. If the aim is never to go fast a "hi thrust" or "saildrive" option might be better (different gearbox aimed at slower speeds).

Using a petrol engine to turn a dynamo to generate electricity some of which gets stored in a battery and then using that energy to turn an electric motor connected to the prop sounds much less efficient than just using a petrol engine to turn a prop.

Most of the electric motors I've seen have plastic props. I'm not sure I'd want plastic props in waters likely to have shopping trolleys etc.


Quote:
Originally Posted by SIBer View Post
I've done some canal barging in my time and the pubs are great as no drink drive laws on the waterways but don't expect your motor and generator to still be on an inflatable after an afternoon pub session!
I don't know what bylaws BW / the EA have - but i'd be surprised if they don't have rules about operating a powered vessel whilst intoxicated. That may not be the same as, nor as easily enforced as drink-driving on the road - but if it all goes horribly wrong I bet they find some sort of book to throw at you, even if it is just the spurious sounding offence of "reckless endangerment".
__________________
Poly is offline   Reply With Quote
Old 29 November 2011, 19:13   #20
Member
 
Country: UK - England
Length: 3m +
Join Date: Nov 2011
Posts: 10
Quote:
Originally Posted by Polwart View Post
A petrol outboard will give out maximum power at 5000 rpm, but it won't do any harm to run it at less than that with a sensible choice of prop. If the aim is never to go fast a "hi thrust" or "saildrive" option might be better
The trouble is, you can't actually get any technical advice from 'official' sources - you can only ever speak to salespeople, who only know how to process cash or card transactions

So far as I can find out, it is best to run an outboard at its maximum power, and the only way to ascertain a 'sensible' size of prop is by (very expensive) trial and error - the options you mention may indeed be better, but, in the 2-3hp range they are probably not available

Rookie
__________________

__________________
Rookie is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off





Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -5. The time now is 22:32.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.