IanD
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Posts posted by IanD
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26 minutes ago, beerbeerbeerbeerbeer said:
For a few years I used a set of bunkbed ladders to get up on to the cabin. A stool is also good to use as a hop up. A stool also comes in handy as a foot rest when seated up on side steering.
Over time I’ve found ways to avoid using most lock ladders but there are still plenty of occasions when I need to use the lock ladder and something to hop up or down to and from the cabin.
Same here -- luckily I can use the lockers in the semi-trad stern to step up onto the roof (or get down from it), so no ladders or steps needed... 😉
(and the low cabin at the bows, if I ever need to get onto the roof from there -- which I haven't ever had to do so far...)
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30 minutes ago, magnetman said:
So despite the standard shaft cone you can't put a different prop on the E Tech?
Not unless you want to run at much lower rpm and maximum power output -- the problem is that to swing a decent size prop you need high torque, and small direct drive motors don't have it.
And while overpropping might work fine on a diesel boat which has lots of power to spare so can afford to sacrifice some, it's not a good idea on an electric drive which has much lower power.
Sorry but all this is basic engineering stuff, you can't make it go away just because you don't like it... 😉
Let's take the 10 POD for example, because it looks as if this one is torque-limited -- so power drops with rpm:
10.9kW 1470rpm 13.6" x 7.9"
9.3kW 1250rpm 14.5" x 8.9"
7.4kW 1000rpm 15.9" x 10.4"
So yes you can put a bigger prop on it to get lower rpm and noise, but only by sacrificing a lot of the (already small) power output -- and I'm fairly sure 10hp maximum output isn't going to be what most sensible narrowboaters are looking for... 😉
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Just now, magnetman said:
The 10 is better.
It's still a horribly small noisy prop... 😞
15 POD -- 11.5" x 5.8" at 2240rpm10 POD -- 13.6" x 7.9" at 1470rpm
For comparison:
Engiro -- 17.2" x 11.4" at 1080rpm
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10 minutes ago, magnetman said:
What about the E Tech 15kW pod motor referred to earlier?
Do.you think there is a gearbox in there?
Maybe they need one.
I will ask again.
Can you find a pod motor with a geared drive which would push along. narrow Boat? You did suggest earlier that such a thing exists. Who makes it?
No I didn't suggest that, I said that small pod drives were either geared or too high-speed for narrowboats -- with direct-drive ones (like the DIY one in the video) the motor is simply too big.
That 15kW ePOD drive spins the prop at 2250rpm -- if you think that'll be quiet pushing a narrowboat along, I have a bridge you might want to buy... 😉
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3 minutes ago, magnetman said:
Can you point me to a 10kW pod motor which is not direct drive
Good luck finding one.
I'm going to turn that round -- you find one which *is* small and direct drive and doesn't have a small noisy egg-whisk prop... 😉
Those annoying old laws of physics suggest you won't... 😉
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3 minutes ago, magnetman said:
Are you sure about that?
Torqeedo originally did exactly that (RC plane motor and planetary gears) but I don't think the larger pods do. I am pretty sure they are direct drive.
The really large pods -- like are used on ships -- use direct drive. The ones under discussion were the small boat ones which (mostly) don't, at least if you want a relatively low-speed prop like on a narrowboat not a high-speed egg-whisk. See all the discussions about prop size and rpm... 😉
The Mothership and Finesse motors which are seen as "best-in-class" direct drive for narrowboats are far too big to get into a sensible-sized pod -- for example...
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17 minutes ago, Tonka said:
Is that why you don't see solar panels on ballrooms?
Didn't know they were banned
We've played gigs with wooden floors with "No Stilettos" signs on the wall. Not everywhere, but quite a few places. I assumed "some" would be implied... 😉
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3 hours ago, Asteroza said:
I think the pod in the video seems rather large though, though supposedly that's for ease of maintenance as it was a prototype.
Here's some 15KW pods that look smaller
https://alphamarineequipment.com/product/aquamot-trend-outboard-engine-15kw-35-hp/
https://greenboatsolutions.com/shop/motor/outboard/aquamot-a150e
https://shopetechdrives.com/shop/E-Tech-15-POD-Outboard-15kW-72V-p560682575
The Rim Drive Technologies hubless ones do come in both fixed style like the ePod or as a regular outboard.
A typical rudder skeg with half cup bottom bearing, or just needing to lift an inch out of a bottom cup before rotating up, would allow an outboard installation with an pod having a fin below the pod with a bottom nub to interface with a skeg with protection and bottom support for thrust perhaps? For a hubless ring, just having a round nub at the bottom of the ring to interface with the skeg bearing cup should manage...
Won't do anything for cill attacks (unless you had a recessed notch in the stern to place the vertical rod of the outboard farther forward), but you would be facing similar protection issues with existing rudders right?
The pod in the video is large because a direct-drive electric motor is big (high torque, low speed) -- the one in my boat is even bigger than this and weights about 50kg.
The commercial ones with a hub motor (and open prop) use a small high-speed motor and gearbox to reduce the size, but this puts the cost through the roof. The rim drive ones don't need the gearbox but now have to seal the motor while allowing drive to the prop, hubless will make it much less prone to fouling. Both types -- if also steerable -- still have the damage problem unless they're protected by a skeg or hull (see below).
As I said, there's no doubt that a pod drive suitable for canal use (robust and with a skeg/bottom bearing) *could* be made, but it would be even more expensive than the standard marine ones (small volume, high development cost) and almost nobody would want to buy it as a result (boat completely depends on it, nobody would buy it used) -- so it's not going to happen.
Rudders can (and do) get damaged by cilling, but they're just a steel plate than can be either bent straight again or even replaced quite cheaply.
If you sit a 20t narrowboat down on one of these pod drives -- or reverse the boat into a cill or other underwater obstruction, or maybe even ground it on something solid on the canal bed -- it's likely to cause major damage to the drive and/or the bearing/hull fitting, they're simply not designed to take this stress. That's likely to mean a bill of many thousands of pounds for repair/replacement, given the purchase price and the fact that even a replacement ePOD propeller costs about £2000.
The only solution is to hide them away inside the hull (or between pontoons, whatever) which is what is being proposed -- but this will lead to huge access problems if something does get round the prop, including horrible stuff like barbed wire, fishing nets and so on. Putting it behind a grille sounds great but simply isn't going to work on canals full of leaves and weeds.
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31 minutes ago, Rod Stewart said:
Well, thats a relief. I had one of them smooth ones once. It was as slippery as a <insert appropriate slippery thing here> after it got wet. Thankfully, i stepped on it one day and it broke, so I got some sensible rigid ones instead.
I've walked on mine in locks with no slipping or damage, they're designed for this. Wouldn't do the same in hobnail boots or stilettos though, for the same reason they're banned from some wooden dance floors... 😉
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51 minutes ago, Rod Stewart said:
Can they be fitted with that antislip paint stuff?
They don't need to be, the surface is rough enough to be safe to walk on.
The crosswalks between them do have antislip, as you can see in the photo.
50 minutes ago, Tonka said:But we don't know what long term damage they are doing. Bit like vinyl roofs on cars
What kind of damage do you think a fibreglass/aluminium composite panel vacuum-bonded down onto steel over the whole area*** is going to do? There's simply no mechanism for water or air getting in to cause any corrosion, any more than there is with anything else impermeable glued down to a surface.
Vinyl roofs are completely different, just a thin skin of permeable plastic that deteriorates over time and sunlight. You might as well say that because building a boat out of vinyl would be stupid, so is building one out of GRP... 😉
*** assuming they're fitted properly like this, not a DIY bodge job... 😉
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It's perfectly possible to have lots of solar panels which don't spoilt the look of the boat and allow you to walk along the roof in a lock, like this -- green in all possible senses... 🙂
Too expensive for most narrowboaters though... 😞
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3 minutes ago, nb Innisfree said:
Dead easy to weld, but Unobtanium is very difficult to obtain and it's very very expensive, priceless in fact.
I know some people who seem to disagree... 😉
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2 hours ago, magnetman said:
Loads of Boats have outboards weighing well over 100kg. This canal Boat only needs a 10kw pod motor on it. Nothing especially powerful. If it is heavy then hydraulic actuators with an electric motor will lift it out. Just like a normal power trim tilt outboard.
Having a pod motor permanently installed means you have to dock the Boat if there is a propeller problem. Weedhatch needed. Hole needed in hull for the steering..
With a lifting outboard style installation you jack it out and work on it in situ. People like outboards for that. Very convenient.
The transom would obviously need reinforcing and the arrangement would not just be clamped on like a dinghy outboard.
It doesn't take a particularly powerful motor to push this Boat along
It the swim was conventional and you had heavy batteries rather than batteries + ballast the motor could be arranged to turn 180 degrees and thus be a starn thruster as well as a drive motor.
The reason I keep going on about heavy batteries is because you get something which is heavy. That is what you want in order to get the Boat down in the water. Using ballast wastes space. It would be interesting to calculate the differences. LTO would be nice here as they are quite heavy.
Normally people want light batteries but not always.
Almost anything is possible if you spend enough time, money and engineering effort on it, including a steerable liftable pod drive for a narrowboat.
Whether it makes sense to do this -- and whether anyone is willing to pay for it being designed, manufactured and fitted (and repaired if it's damaged!), in a completely custom boat that nobody will want to buy if it doesn't work -- is another issue entirely.
There are many very good reasons why a conventional prop (possibly with a Schilling rudder...) with an inboard motor is by far the most popular solution on narrowboats. To put a number down on paper, a typical 15kW/20hp electric motor will give about 200kg thrust at the propeller, which the mounting and leg/prop has to support. However a much bigger issue is what happens if it catches on a cill as the boat drops or reverses, which is why a bottom bearing on a skeg is a far more robust solution for canal use than a leg-type drive.
If you want to use a (very expensive!) commercial pod/leg drive (steerable or not) on the canals then protecting it from such damage is essential if you're not going to risk possibly ruinous repair bills, and AFAIK all such pod drives just mount to the hull at the top so you have to add extra damage protection -- the DIY drive in the video is no worse for this than a normal prop/rudder since it's open-propped and mounted above the skeg.
And if you protect a commercial pod drive (like the ePOD in the HDPE boat) it becomes even less accessible.
The only sensible solution if you want to go down this route would be a better-engineered version of the steerable pod drive in the video, with an open (or hubless ducted prop) and a skeg/bottom bearing -- either with a smaller better-streamlined motor in the pod (also needs a gearbox, more money...) or the motor vertically mounted inside the boat like a drive leg. But no pod drive supplier is ever going to develop such a thing because the cost would be high and the demand tiny compared to pod/leg drives intended for open-water use, which also often used ducted props for very good reasons which also don't apply to canal use... 😞
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8 hours ago, ditchcrawler said:
Did we have this one on here, I can't remember
We did, but that's rather different to a small outboard and has a lower skeg bearing to take the thrust off the upper one -- and remember one reason for suggesting this was so the pod could be swivelled up out of the water for prop clearing. All fine with a teeny 4hp outboard, not so much with a much heavier duty drive, raising this up would be a major engineering challenge.
The only sane pod-based drive solution for a narrowboat is one which is and stays submerged and is steerable, like the one in the video. And for reduced blocking/jamming it either needs to have an open prop like the one in the video, or if it's a ducted prop it needs to be hubless like some (expensive!) commercial ones -- grilles to prevent this are simply impractical on weedy/leafy canals.
So the ePOD fails in two respects, it's not steerable and it's ducted but not hubless... 😞
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3 hours ago, ditchcrawler said:
If the rotating equipment is 10" above the water level that problem goes away. This old what looks to be a Seagull shows that
The problem with doing that with a prop with enough thrust to propel a narrowboat -- several hundred kg at full throttle -- rather than a weedy little outboard is that you have a large sideways force applied a couple of feet below the bearing. That's a lot of stress on both the bearing and whatever it's mounted on -- which is where HDPE being a lot weaker than steel might well cause a problem...
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2 hours ago, Chris Lowe said:
I've still yet to get the keeper plate off my Sea Searcher, my old magnet is very weak compared to it.
Before struggling with it, take your wallet with any credit cards out of your pocket and put it somewhere safe, they don't like powerful magnets. DAMHIK... 😞
(though in my case it was installing an 18" PA driver with a mahoosive magnet that weighed about 40lbs that did it...)
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46 minutes ago, nb Innisfree said:
Don't forget you can't have a shallower draft without less interior headroom, modern canal boats are usually approx 7' from exterıor surface of bottom plate to top of roof to ensure bridge and canal bed clearance, (when going under bridge) I doubt there is enough space for conventional concrete ballast.
As I said earlier, there are few places on the canals*** where a boat with a bit higher air draft couldn't pass, just like all the boats who cruise around all the time with stuff piled on the roof or sticking up from it -- and most boaters probably won't ever hit (literally...) any of these low pinch points, unless they're rather more adventurous than many... 🙂
If the return for not being able to use these restricted parts of the canal system is that battery power use is halved and/or range is doubled, I expect most people would think this is a price worth paying... 😉
*** yes I've been through several of them, but then how many people ever actually go through Standedge or Froghall or Gosty Hill or...?
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5 minutes ago, hoopdriver said:
That’s another possibility. My main worry is that running the engine doesn’t charge the battery. The consensus here - and I’ve had some wonderful support and advice today - is that there may be a blown diode in the domestic alternator
A £10 DVM will confirm whether the voltage is 1.4V or 14V... 😉
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27 minutes ago, magnetman said:
You will notice I never mentioned lead acid 'domestic' batteries.
Anyway just out of interest how much did the battery bank on your Boat cost and what is the capacity in kWh?
I think you said you went for LFP which does seem to be a good choice. LTO might be better but is quite expensive.
Example
GF06180V Sonnenschein Gel Battery 6V 200Ah
£314.99 Inc VAT
Guaranteed next working day delivery on orders before 1pm
GF06180V Sonnenschein Gel Battery 6V 200Ah quantityAdd to basket
PRODUCT DESCRIPTION
The GF-V range of blocks are suitable for hard industrial use. This includes applications for advanced guided vehicles, mobile elevating work platforms, cleaning machines, walk-behind pallet trucks, electric cars and buses.
This means that no maintenance whatsoever is required throughout the entire service life of the battery. The special advantage of this Sonnenschein dryfit battery lies in the batteries’ suitability for extreme operating conditions and the highest demands on reliability.
I don't know what the actual cost was, I bought a boat not batteries... 😉
IIRC the retail price for the Winston 700Ah cells (2.24kWh) at the time was about EUR800+VAT, call it £800 inc VAT -- that would be £13k for 16 of them (36kWh, £360/kWh), but I somehow doubt that Ricky paid the retail price.... 😉
Sounds a huge amount, but to put it in context it's roughly 4% of the total cost of the boat, which isn't a lot given that it's an essential part of the drive system. I think the generator cost about the same... 😞
(and for comparing with LA, don't forget effective capacity of LFP is getting on for 2x higher accounting for usable SoC and LA capacity losses/inefficiency)
14 minutes ago, shaun15124 said:We will show a picture of our work on the ballet set, which I assume will use breeze blocks. The water ballast is only for the two tanks.
I would hope the ballast uses engineering bricks, not breeze blocks!!!
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10 minutes ago, magnetman said:
Yes but they are ballast.
This is a Boat being built for customers.
Ballast is cheap. LA domestic batteries with shorter lifetimes which need charging for hours and hours regularly to prevent sulphation, can only use half their capacity, don't like fast charging or discharging, waste a chunk of the input energy (e.g. solar) due to round-trip losses, and cost more per lifetime kWh have no place in electric boats nowadays. Or maybe any new boats... 😉
(they're fine for cheap starter batteries, high current occasionally for very short periods)
Their only advantage is that they're a bit cheaper to purchase upfront than LFP -- though I'm not sure even that is true nowadays for the same *usable* capacity, especially at high charge/discharge rates like electric boats or boats with heavy-duty 230Vac on board.
Using LA batteries for this purpose is misguided short-term penny-pinching, which will cost more in the long-term -- the "British disease", in other words... 😞
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2 minutes ago, magnetman said:
It is interesting to observe that even really quite expensive electric Boats are still fitted with Gel type lead acid batteries.
Obviously we all know that lithium chemistries are far better but the Boat does need to sit down in the water.
Another point about using an inbuilt outboard is to make the customer feel happy about potential repairs.
You can point out that the motor can be removed and substituted for another the same in 5 minutes if it stops working. The product (HDPE canal Boat) is aimed at people who want convenience
I know it seems odd but most people can vaguely understand an outboard. Its convenient. You see them in films. Everyone's uncle has one in his shed.
A high tech inboard is a bit of a mystery. An outboard is 'accessible' to more people.
I really hope they're not seriously proposing using LA batteries, these have *so* many disadvantages compared to LFP -- they're not even cheaper over lifetime any more...
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6 minutes ago, shaun15124 said:
Oh, that is interesting as well; it's very similar to what we have done. I will show better pictures in due course to clarify what I mean.
If each cellular compartment is watertight (with small access holes at the top to fill/empty them) you could get about 300kg of water ballast in per 1m of boat length (about 5t total) for trimming which could be adjustable after fitout... 😉
(aren't you going to need to get ballast into here anyway?
Welding on the inner beam skin would be the ideal, but you could also use multiple bolts through into tapped holes in each beam with epoxy glue at the rib/plate joints-- or maybe into epoxied-in tapped metal bushes to stop the thread stripping?
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22 minutes ago, shaun15124 said:
[snip] -- but completely agree 🙂
Your suggestion of using a cellular beam structure by adding a second HDPE skin on the inside of the ribs is fascinating.
The concept of increasing stiffness this way while regaining internal space is very appealing, and it’s something we’ve actually explored in part during the design phase. However, as you rightly note, the challenge lies in execution. Welding HDPE in such a configuration presents significant difficulties, particularly in ensuring consistent strength and a watertight bond between the skins and ribs.
Ultimately, we’re focused on finding a balance between maintaining hull rigidity and optimizing the internal space without making the manufacturing process overly complex or cost-prohibitive. Your insights reinforce that this is a critical area for innovation, and we’ll definitely take these ideas on board as we continue refining the design.
Thank you for sharing this—it’s precisely the kind of thought-provoking input that helps drive improvements!
You don't necessarily need to do this for the sides of the hull; if you can work out how to make just the "baseplate" a very stiff (e.g. 150mm) relatively thick cellular beam, then this should give enough bending and torsional stiffness to the hull as a whole to allow a single skin with ribs for the sides, which will also make fitout much easier -- like the bottom half of the bridge cross-section. You could also make each gunwale from a thick-walled square-section tube to add rigidity here.
IIRC the ribs in the cellular beam should go crossways (not lengthways) for maximum torsional stiffness, which is probably what you want in a boat... 😉
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24 minutes ago, shaun15124 said:
the boat fitter was happy with this as we showed him all these sizes
which we can change for the next one thank you for pointing this out
we can reduce the width in the' ribs' for the next one
If you reduce the width of the ribs this will also significantly reduce hull strength and rigidity, as I'm sure you're well aware -- square of rib depth, so half the depth means 4x as many ribs (or 2x as many each twice the thickness).
The best way to restore this while reducing depth is to turn the hull structure into a cellular beam (like the Britannia bridge over the Menai Straits) by adding a second HDPE skin on the inside of the ribs, this hugely increases stiffness compared to a single skin with ribs -- you can probably save something like 3" on each side and get back the stiffness with a similar internal space to a steel hull.
Might be difficult to build though, I can't see how you can weld the second skin on... 😞
(the option Robert Stephenson used of sending a boy with a rivet gun down the 21" square cells isn't going to work...)
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HDPE canal boat
in General Boating
Posted
It does, and it has a reasonably high-torque motor and a ducted 7-blade prop, all good for low noise -- as Vetus rightly claim 🙂
Two huge negative points though; it's not steerable (surely the entire point of a pod drive?), and if debris damages the "easily replaceable" prop -- which can't be bashed back into shape, it's composite not bronze -- it'll cost you about £2000 for a replacement.
Always assuming you don't damage the pod itself, which will cost you about £10000 to replace... 😉