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We have a 500mm domestic cooker complete with electric ignition which needs the inverter  on to operate, we also have a domestic sized shoreline fridge capacious and very good. Incidentally the cooker came with the necessary jets and has a glass lid which acts as a flame cut off as well. Some over zealous BSS  inspectors wont allow a cooker unless it actually states in the cooker bumf that it can be used on a boat. Go figure. 

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If you have such an inspector, I suggest you ask him to show you the precise passage in the BSS that says such a thing!! Or perhaps someone on here could point me in the right direction if I am wrong!!

I believe thats a hangover from the days when "boat cookers" had FFD,s and ordinary household cookers did not but nowadays all household cookers seem to have them as I suspect they are a requirement in tenanted properties now and as such I believe they are no longer an issue!

No doubt someone will come along and perhaps tell me otherwise.....?

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2 hours ago, marshman said:

I believe thats a hangover from the days when "boat cookers" had FFD,s and ordinary household cookers did not but nowadays all household cookers seem to have them as I suspect they are a requirement in tenanted properties now and as such I believe they are no longer an issue!

This raises several points which I hope I can help to clarify.

About 5 years ago, Electrolux brought out a room sealed gas fridge, which they announced as suitable for use on boats. Indeed it is, but it would be prohibitively expensive to install. Before then, Electrolux always specified in their tech sheets that their fridges were not designed for boats. This was their "get out of jail" card, since there were thousands of these installed on boats all over the Broads and (I am ashamed to say) most of them were installed wrongly anyway. Not all of them survived. Very many, in the late 60s, became the ignition source for gas explosions on boats.

Nowadays, I would suggest that a gas fridge on a boat is no longer practical, which is a shame as they were very efficient.

In 1996 it became European law that cookers on boats had to have a FFD (flame failure device) on all the burners as well as the oven and grill. This was a very good idea, since the big risk on a boat is the gas flame blowing out, due to the draughts when you are going along with the canopy open, and have just put the kettle on! Problem was, no British manufacturer, at that time, made cookers with FFDs! Nowadays there are several suppliers of which SMEV is a very good one.

To answer your question, if any cooker is installed in a boat with due regard to its gas supply piping; its siting away from other flammable materials; its firm fixing and the fixed ventilation in the living space, then as long as it is fitted with FFDs on all burners there would certainly be no problem with ERCD regs, which (I assume) correspond with BSS in this respect.

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Personally speaking I would go with a cheap and cheerful domestic fridge - there so much cheaper than marine versions (about £100) to £120) and can be considered 'disposable' when they eventually kick the bucket. All the time you are in the marina power to it is not a problem, however once you depart on your cruise you would need to have an Inverter to power it.

You could get a new battery (or 2) and an Inverter and your domestic fridge and still not have spent as much money on a Waeco 12v marine fridge. The only thing you would need to consider is that you would be using 36Amps every 24hrs - may be more and at that sort of rate, coupled with say heating use, lighting you must run your engine ever day to replenish the power from your batteries.

I wrote a bit piece about a freezer set up but on 24v DC with an Invert a couple years ago, below is the findings to give you some food for thought:

This is only my view, but I seriously consider 12v power use on a boat as no longer required.  I would much prefer to see all DC power use being run at 24v because this reduces your amperage needs, and in many cases reduces the gauge of wire needed.  I know sometimes what you have (in your case the bow and stern thrusters) will be 12v and so that would not be much helped by the rest of the boat being on a 24v system.  But when you look at everything from electric toilets, bilge pumps, lighting, engine gauges etc they all come in 24v versions these days and often at no more cost than their 12v cousins.

Disclaimer: My Maths is not that great so anyone wishing to correct all this please do so...

Now back to Freezers (or Fridges) if you bought a domestic 240v model you would need to run it off an Inverter, and that should be and a Pure Sign Wave one too.  I’ll say for the sake of this example you’ve stuck with 12v so what you need to do is find out the wattage the unit consumes (I’ve seen a compact one on Amazon that uses 0.45Amps @ 240v). Link: http://www.amazon.co.uk/dp/B013R42QD4 

This means your running wattage would be 108w but the compressor motor also needs a jolt of about three times its running wattage to start up, usually provided by a hefty Capacitor, this surge is needed for only a fraction of a second but the inverter needs the beans to provide this so just to start the freezer you would want to factor in say 400w which would reduce once running.  A nicer 2,000w pure sign wave inverter therefore would be handy. Even nicer if it incorporated a 70Amp battery charger – so here is the beast – and it is coming in at 22KG. Link:  http://www.amazon.co.uk/dp/B00PYK573G  (You will see these branded as Sterling combi Inverters for £995.00, no kidding!)

Now, you need to know how much DC battery capacity you’ll need to have to run the Freezer.  I would personally have dedicated batteries for this task so in the worse case you lose some food not a bunch of other more vital equipment if the batteries are drained.

So, let’s convert the Freezers AC running Watts to DC Amps. The starting wattage doesn’t last long enough for me to worry about, but we know our AC wattage is 108w because it uses .45Amps at 240v. Divide this by 12 (our DC volts) and multiple the answer by 1.1.  So 108/12x1.1= 9.9 - you would therefore need as good as makes no difference 10Amps DC to run the Freezer.  I understand that you should multiply by 1.1 to take into account the loss an Inverter (or inefficacy) it causes thus actually would require slightly more DC Amps than a ‘pure calculation’ of Watts/Volts = Amps

Now the above is only valid if the Freezer ran for an hour continuously, and in such time drew 10 Amps – so with this in mind  this would equate to 10Ah (Amp Hours). Now this if it were to run for 24 hours that would use rather a lot of amps - to break it down to a nice round figure I will say that the Freezer might run for 20 hours continuously (highly unlikely) which would equate to 456Ah!

Freezers do not run consciously for 20 hours though (if your does you have an issues lol) – some say when calculating power with regard to Fridges and Freezers to work at a 50% run time per 24 hour period. I’ll go along with this for now but I am not so sure this is true. So, our 456Ah would reduce down to a more ‘manageable’ 228Ah being taken from the battery bank.

This is still not making me happy; because the above is like saying that a Freezer will run (on and off) but effectively, none the less still be running for 10 hours in every 24 hours.  I just don’t believe a compact A+  rated appliance would run for 10 hours every 24 hours.

So let’s dig deeper into the specifications of the Freezer and see if this helps matters. I find its Kilowatt Hour use per 24 hours is 0.4 (Kwh/24H): 0.4) or in ‘easy speak’ that is 400 Watts.  This is reference to a 240v supply, but it gives a good idea that in a 24 hour period it would consume 400w if plugged in at home.

With this information we can now find out just how many Amps the Freezer is actually likely to sap out of your batteries in a 24 hour period and if my math is right, that means 36Amps. (400/12x1.1=36)

On the face of matters that appears you could just use a single 110ah Battery and with careful thermostat control run the Freezer off this. Personally, I would opt for two to split the load over them and take into account the 88 – 90% efficiency an Inverter can provide and that you cannot comfortable discharge more than 50% out of a lead acid battery. Your usable capacity with just a single battery is 55Ah (110ah with two).

As most boaters these days wanting  higher wattage  Inverters  (and often chargers too) these are now a given to be on board the modern boat. Why then does the modern boater still need to pay hundreds of pounds for a 12v version of a Fridge or Freezer when you can use cheaper, easily replaceable domestic varieties.

So, it goes to show however, if you had a 24v system, with an Inverter that took 24v in and gave 240v out your amperage need would not be 36Amps each day for the Freezer to run but come down to something like 18Amps which is why I like more volts at DC and keeping the Amps down

 

 

 

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Thanks Vaughan - the truth is out!! In the UK now it is virtually impossible to buy a new domestic cooker without FFD's and I think that is following the fact, I believe, that tenanted properties now need them too. As a result all manufacturers now produce them and a quick look on Currys website will confirm that.

Therefore IMHO the statement by Vaughan is absolutely correct and as a result you should not be conned into buying an overpriced "boat" cooker - just buy a bog standard one but make sure it has FFD's. Oh and save probably the best part of £300!!

Myth exposed!!! Boat cooker manufacturers can now stop coining it and reduce prices! Some hopes, plenty of mugs still around!!

 

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13 hours ago, marshman said:

- just buy a bog standard one but make sure it has FFD's. Oh and save probably the best part of £300!!

I think I ought to qualify that the cooker will still need to be installed to the manufacturer's instructions, which will show what distance horizontal and vertical, will be needed away from flammable materials such as bulkheads and the deckhead. It will need to be type-approved with a kite-mark or CE (Communité Européen) mark. It will come with jets for natural gas and these will have to be changed to butane or propane. It will need piping of the right size for the length of run from the bottles and it will need a testing point beside it, to ensure that gas is at the correct pressure when 2 burners are alight. Plus several other points of detail.

In other words, it is a job for a qualified fitter on a boatyard!

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 I did my own gas piping, it's not difficult, before the boat going all electric. Living here in Norfolk, home cookers are available already set up for bottled gas, as natural gas is not available outside of the major towns and Norwich.

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Thanks for all the advice, ended up going for a Voyager 4500 as its a similar size to the old Flavel so nothing will have to be modified to fit it, still undecided on the fridge as the space we have is very narrow and I'm not finding anything that will fit at the moment..

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Did you buy a boat to be within 24 hours of a shore power hookup or to go boating? I'd go for the option that means you can spend a couple of days without having to run or be within hookup distance, you've paid more than the cost of a good fridge for the boat so why scrimp now and be reliant on inverters and big battery banks.

Forget the 3 way options as on 12v they are absolute battery killers, 12/24v compressor fridge every time for me.

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