Hawksbill

Thank you Matty, I’ve spoken to AR Parchment but they unfortunately don’t supply them. /Rob Mistype - I meant AR Peachment Mistype - I meant AR Peachment

Thank you David, very helpful I’ll look into the links provided there. /Rob

Hi, I have a BCS bow thruster model BT120N but the prop has just broken; though it’s not often used can be extremely useful eg reverse marina parking in windy conditions on our 68’ narrowboat and I’d like to get it fixed, however spares no longer seem to be available. I need to find an equivalent prop and locking nut to replace it, any help would be gratefully received. Rob

Thanks for all your input which has been incredibly helpful - I will investigate the best way to go over the next few weeks (mainly probably between 1. using a VSR to parallel the BT and domestic battery only when the charger is on, and 2. second mains battery charger at the bow for the BT battery). Just one question re the comment on concern over cooking batteries over a long period, say if on permanent charge: Would leaving a 240V charger permanently (ie when on shoreline, which is 24/7 when not running the engine, as I’m in a marina and not a live-aboard) trickle charging the 24V BT battery really be a risk to the battery - after all, that’s exactly what’s happening with the main domestic 24V bank being charged mainly 24/7 through the Combi charger when attached to shoreline?

Thanks for the suggestion on the Hancock batteries. Re:”Switching between start and BT batteries is a much more sensible option than between domestics and BT, because your start battery is generally fully charged anyway, but I'm assuming like me you have twin alternators?”, yes I have twin 24v/12v alternators feeding domestic and starter battery respectively when engine is running.

Thanks Jen, also an excellent alternative suggestion. Given the engine 24V alternator at stern is currently charging the BT battery, then I’m assuming as Tony says there must (or should) already be thick 24V cables running from stern to bow, however a second independent charger for the BT potentially sounds a more simplified solution. Also sounds like we’re agreed it’s really advised to have that BT battery permanently topped up rather than rely on purely engine charging which is good feedback thanks.

Thanks Tony and Tracy for the really helpful advice. I’ll look into truck start batteries, any ideas on sources for these? I can confirm the domestic batteries are 24V, which are charged by a Mastervolt Mass Combi 24/2500/60 inverter/charger, so your suggestion to use a VSR to charge both domestic and BT batteries in parallel sounds a good way forward. You raise a very good point on the BT thermal cutout which it does have - so can’t rule out cutting out due to seizure / fouled prop, I thought it was unlikely though due to the initial ample 2-3 second ample thrust before cutout, I thought if it was due to a seizure you wouldn’t even get that hence my immediate thought being a shot battery. I haven’t worked out (yet) how to get into the BT tunnel to check if there could be a foiled prop, I’m assuming this could only be done with the boat out of water - as there’s no weedhatch equivalent like on the main prop , sorry if I’m missing something obvious as it’s all new to me.

I have a problem with the bow thruster in my NB and am seeking some battery and charging related advice please so I can decide best way to move forward. I purchased it a few months ago - first boat I’ve owned and loving it, although I’ve rented boats for holidays over many years - and it came fitted with a 24v / 8kw bow thruster. [Aside: I know some folks opinions on BTs , I know they’re not essential but at 68’ long I’ve found it quite useful as a manoeuvring aid at very limited times when reverse mooring etc, so appreciate to keep advice away from ‘you don’t need one’ 🤣]. Current immediate problem is it will provide initially good thrust, but for only 2 or 3 seconds before stopping completely. I believe the reason is, because initial thrust is good before expiring the current batteries are shot - so once I confirm this I will need to replace them. It currently comes fitted with 2 x 12V 180aH dual purpose (which I understand means suitable for both general purpose or starting purposes) leisure batteries, sited very close to the BT. So I have 2 questions: 1. Someone has told me that although the current batteries are ‘dual purpose’ leisure batteries so theoretically should be fit for purpose, they would recommend replacing with dedicated starting/cranking batteries. These would however be a lot more expensive, so does anyone have experience/knowledge of the trade-offs of dual purpose vs dedicated starter type? 2. Once I select and fit the replacement batteries, another dilemma: currently the BT battery is only charged by the engine - not shoreline. But looking at the scenario of using a BT, it’s typically used for a short time with very high power - and often when coming to the home mooring, just before switching off the engine and switching to shoreline power. I’ve heard that unless you can ensure the battery is kept fully charged for most of the time, a new battery will quickly be destroyed. I’m not a live-aboard and can’t typically run the engine for an hour after coming home, so in folks experience should this be a real concern? If so I’ll then look at options for adding another dedicated 24V charger which could permanently trickle charge from shoreline power (main concern being to add more cost/complexity) Any constructive advice gratefully appreciated.

Really useful feedback all, many thanks!

Yes I meant ABOVE Teddington, sorry for causing any confusion in the topic title, thanks Athy for amending. Thanks for all your replies, really good to know. Great forum this, first time I’ve used it, what a great community.

Thanks Dave very much for quick reply. Sorry if I wasn’t clear, yes I’m aware we won’t be able to moor before Teddington. What I meant was, by time we’re past Teddington and so able to moor on non tidal section how easy will it be to quickly find a mooring in failing light. But from your answer it seems it should not be too much of a problem (no problem if we need to pay).

Please advise, fellow boaters to us as relative novices!.... We purchased our NB a week ago on the Grand Union in Northamptonshire (so looking forward to spending time on it with our kids / grandchildren) and making steady progress towards our home on the River Wey. We have booked passage to Thames in main Brentford Lock 101 at around 5.30pm this Wed headed upstream towards Shepperton. But though we’ve had several weeks previously on Thames on hire boats (where we got the river / canal bug) we’ve never been this far downstream on it. My worry is, leaving Brentford as late as 5.30pm so getting through Teddington maybe 8pm and having to moor fairly soon due to light, will we be able to quickly find any mooring on this very busy stretch of river before dark, are mooring spots very limited? Maybe I’m worrying too much but any advice appreciated please.