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To go with what router -- 4G or 5G, 2x2 MIMO or 4x4 MIMO? What's your budget? As a rule 5G antennae cost more than 4G and 4x4 MIMO cost more than 2x2 MIMO, but in both cases you get either better coverage or higher data rates for the extra money -- assuming there's a 5G signal where you are. However a decent external 4x4 MIMO 5G antenna (e.g. Poynting or Panorama) is likely to cost more than £200... 😞 https://www.3grouterstore.co.uk/product-category/5g-antennas/4x4-mimo-5g-antennas/

Most modern routers and devices switch automatically between 2.4GHz and 5GHz depending on signal strength -- 5GHz has a lot more bandwidth and channels so much higher data rates when you're nearby but signal drops off faster with distance than 2.4GHz, which gets used for devices a long way from the router. Some devices can bond both bands together for better speeds in the "in-between" ranges, but many don't bother. There's no data rate prioritisation of one device over another by the router except on signal strength, ones with better signal get higher data rates. Newer devices also tend to support higher data rates, especially on 5GHz where they can bond channels together. Different devices can have better or worse RF performance as well, depending how much effort the manufacturer has put into this as opposed to appearance and flashy features... 😉

That's not what the numbers show: the GiffGaff MiFi is on O2, if you compare the iPhone with the Lyca MiFi (both on EE) it's faster. Phones nowadays use MIMO, and are pretty good when outside a boat -- but a good MIMO router with an external antenna can be better if the antenna is a good one and cables are short, which they often aren't. Also not all phones are equal, some have better RF performance than others but this isn't one of the things that is usually tested -- same applies to laptops and tablets. I compared my boat setup (4x4 MIMO 5G router with external antenna and <1m cables) to my Samsung 5G phone (outside the boat) -- both on EE -- and the router had higher data rates. A different router/antenna and/or a different phone could easily give the opposite result -- but a phone inside a steel boat will almost always be worse than a router with external antenna.

First rule of narrowboats : the optimum size of *anything* is always bigger than you can fit into the space available... 😉

Why is a tensioner needed, so long as the alternator can be swivelled (as normal) to set the belt tension? (one would he needed if the end pulley positions are fixed, like when driving a camshaft)

Yes it is, so long as you're happy with Three -- which many are, but UK-wide coverage (especially rural areas) is not as good as EE. I'm going to try using it as my main SIM and see what coverage and data rates are like compared to EE, which I have on my phone -- and also on the 1pmobile SIM as backup.

Unless I'm missing a Scancom special offer, £99 for 17 months (until 8/8/2025) is £5.80pcm... https://www.amazon.co.uk/Three-500GB-Data-SIM-Preloaded/dp/B0BDSH3V49 (always cheaper via Amazon since this includes VAT, prices direct from Scancom are + postage + VAT) (also available is 80Gb is £70/16mths = £4.40/pcm, saving doesn't seem worth it) All these are on Three, EE is *much* more expensive...

If you can send 100G/month to another EE SIM and this SIM is cheap (has to be directly from EE not an MVNO like 1pmobile or Scancom) that could well be your best bet. If not, you can put any SIM from any supplier in the router, whatever gives you the best deal on the best network -- all routers are unlocked nowadays.

How much data do you want/need, do you want it every month or only when on the boat for shorter periods, and do you want to stay on the EE network? To try things out on the EE network I suggest getting a 1-month SIM from 1pmobile, you can top these up with any amount of data as and when you need it. Mine drops back to £3/month for 1G when I'm not on the boat (for remote access/monitoring), when I'm on it I buy a 1-month data boost -- £6 for 4G, £8 for 10G, £13 for 50G, £18 for 200G. For longer-term if you want data all the time, a prepaid SIM from Scancom is considerably cheaper than an EE contract, and a bit cheaper than 1pmobile.

Don't forget that the "unlimited" Scancom SIM has a 600GB "Fair Use Policy" anyway... I got the 500GB one, which is considerably more data than I use from home with multiple PCs and WFH and phones and TV streaming. How much data do you use? AFAIK there's no way to see how much data you've used, at least not easily (right now the 1pmobile SIM is still in the router).

True, but on a single-cylinder engine (with a heavy flywheel) a lot of the vibration coupled into the hull is shaking due to imperfect rotational imbalance (not just firing strokes) and this is the same for both at the same rpm -- when I watched the stern dance it looked pretty much constant every rotation, not bigger on firing strokes (bonk-pause-bonk-pause-pause-bonk...). If the Bolly has a bigger heavier piston than your Kelvin (does it?) this would make the problem worse, also they run *very* slowly at tickover bonkover... 😉

It's a single cylinder (with a big and *very* heavy piston) which means the firing frequency is the same as a 2-cyl 4-stroke at the same rpm but with much poorer balance, and also runs at very low rpm at bonkover -- the whole stern was shaking up and down by several inches several times a second, I certainly wouldn't have liked to be the one standing on it... 😉

Looked like an unconverted working boat, presumably the hull with no steel cabin was more flexible than yours -- hit a resonance and things go horribly wrong, which I think is what was happening... 😞

Not so charming when the entire stern shakes up and down by several inches, like the Bolinder-engined boat I saw on the Trent -- I wish I'd videoed it, the movement was massive... 😉

The idea is to get a large rigid set of bearers/bedplate directly bolted/welded to a massive and rigid part of the hull (often via wood to absorb a bit of high-frequency vibration and add some damping) so that the bearers/hull don't flex -- though as anyone who's been on a boat fitted with a Bolinder will testify another view is that the whole boat doesn't "absorb" the vibrations so much as spread them out throughout the whole hull, which can shake badly in some places at some rpm -- or indeed have the whole stern shake up and down by several inches at tickover (well, bonkover...) going by one such boat I was in a lock with... 😉 It works with slow-speed engines especially if well-balanced -- IIRC the Sabb has an internal balancer shaft to cancel out the vertical secondary vibration -- because the out-of-balance forces which cause vibration go up with the square of rpm, and the resulting vibrations are quite low-frequency so not so offensive. With higher-speed modern engines the vibrations are higher-frequency and would tend to trigger rattles and buzzes all over the boat, so flexible feet are used instead of rigid mounts. But even so there's quite a bit of vibration gets past the feet into the hull which often causes noise and vibration inside the cabin which is worse when the boat is travelling (higher rpm than idle) -- and generators do the same, even with internal flexible mounting feet. The fix for this is the same one that is used for generators in noise-critical places like hospitals, mount the generator on a massive inertia frame which itself sits on flexible feet -- the vibration then stops at the inertia frame instead of being transmitted into the building/boat. This works best with soft feet but is more difficult with engines than generators because of the varying rpm, increased engine movement (Aquadrive or similar essential) and the need to avoid creating new and bad resonances between the engine and inertia frame at some rpm -- and also the inertia frame needs to be at least as heavy as the engine/gearbox which means several hundred kgs. We did this with my generator, it was a PITA (and costly!) to both build and fit in underneath -- the frame weighs about 200kg (almost 2 inches of steel plate!) and is mounted on soft Aquadrive feet, and the extra weight caused some ballasting issues -- but the reduction in vibration and noise inside the boat when it's running is very obvious compared to normal generator mounting. None of which matters to most boaters who are not installing an onboard generator, but those who are could consider doing this if they value peace and quiet... 😉

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