240v Submersible Pump?

[richardm47]

I was looking to buy a Honda WX10 petrol driven water pump for emergency use to help bilge pumps eg with flooding from stern gland or bust sea cock etc. But there's a letter in this month's YM on this subject, suggesting a 240v submersible pump instead. Don't know anything about these pumps but I think it would connect to my Honda suitcase generator, which I already have for charging flat batteries and running fan heater, power tools etc.

What do people think of the 240v submersible pump idea? And what spec pump would I need. Any recommendations on brand and model? I've googled submersible pumps and seen 50L per min pumps for £50 and 300L for £100. Is that about right?

 

[sarabande]

I'd be tempted to stick with the petrol driven ones.

We have a couple on the farm for use on emergency fill ups when the main spring goes dry. They are standard cheap Mole Valley Farmer ones, with a solid alkathene intake pipe and some rollup flexible pipe. One has been in the shed unused for at least three years, and was brought back into service with the original fuel (plain petrol) in the tank. It started a fortnight ago on the third pull . Ricoh is the make.

Some pumps are self priming, so you need to check the draw head first.

A disadvantage would be the fumes if using it below deck, though.


Having said that, I have just seen a Draper 240v 200w Submersible Water Pump With 6m Lift & FloatSwitch, putting out 120l.min for £49.18. Seems like a good buy!

 

[pvb]

Firstly, I think you're being excessively cautious. However, if you're seriously interested in an emergency pump, you should go for the biggest flow rate your genny will power. I'd suggest you look at the Machine Mart range of pumps. These are good, hefty pumps. For reasons I won't go into, I have one of their 2" stainless steel pumps permanently mounted in an inspection chamber in my garden, operating as needed on a float switch. It's been there for years and continues to work efficiently. I have another one which I use on odd occasions when we suffer flooding.

You need to consider how you would get the water from the pump to the sea. Presumably you're not considering permanently installing it. Ideally, you need proper circular hose. If you use the convenient, layflat hose, it will kink at extreme bends and greatly reduce the flow rate. So you might also need to find stowage for a few metres of pipe.

 

[Bobobolinsky]

I bought a new 1" pump off ebay for £12, works like a dream, cost me more for the layflat hose, which I bought at the same time. Any petrol pump is going to have a size disadvantage on a boat, plus you need to carry more petrol. I prefer the 240v route

 

[DownWest]

Be aware that the starting current for the motor will be several times the listed amps. As for size, I have one that is rated at 1,100 watt and shifts up to 15 cu mts/hr. A small petrol one would be my choice, partly because the idea of 240v and a serious leak makes me nervous.
A

 

[Strathglass]

As has been said the drapier type pump are readily available.
Their are many sources around including Screwfix and Toolstation.
But get one without a float as even with the float tied down it would leave too much water in the boat and is something else to go wrong.
They are not the most reliable of pumps and do not like running continuously. I have used them in industrial drainage systems (with floats) but use three pumps which have to be replaced on a regular basis.
Pumps made for ponds are much more reliable and power efficient than the Drapier type but they are very much more expensive power for power.
All of the pumps are fairly well insulated as they are intended to run under water.

I think that it would have to be a very large craft indeed to justify the real estate, weight and cost of a large 240 volt pump out system. (or a very dilapidated leaky old tub)

Iain

 

[mattnj]

for what its worth, i have a Honda WX10 and its brilliant, 6.1kg i think, very compact and easy to use, would be great in a flooding boat situation.

The other option i am looking to do this winter, is change the raw water inlet on the engine so that it has a pickup internally for use as an emergency bilge pump too (move a 3 way ball valve of similar)...just an idea. I dont fancy a running genny and 240v on a sinking ship.

 

[prv]

I'd have thought that in the ultimate emergency situation, the direct self-contained petrol-driven pump is the ideal answer. However, they're big buggers to stow, and I'm guessing not cheap. So unless you have a big enough boat (and hence space and money) it seems an unfavourable bargain against the odds of actually needing it.

If you already have a generator on board, though, I think a decent electric pump makes a much better compromise between cost+stowage and utility in emergency. The pumps aren't all that expensive, and can tuck away somewhere in case it's ever needed.

It hadn't occurred to me before, but I think if I carried a generator (I don't) I'd now be having a good look at the Machine Mart catalogue for a pump.

Pete

 

[richardm47]

Thanks all, some good points I hadn't thought of there.

The dodginess of a running a genny and 240v on a sinking ship had occurred though. I agree with the reservations but thought it would be a useful last resort when desperate. I'd put the genny in the sheltered part of our cockpit, under the hardtop bit. And assume that the pump does what it says on the tin - "submersible" with watertight electricals.

Hadn't realised that the £350 Honda WX10 weighs only 6kg. That's tiny - half the weight of my Tohatsu 3.5 2-stroke outboard! and only 2kg heavier than an equivalent (140 l/min) 240v submersibles. That takes away the weight advantage that I thought electric would have. Electric is still much cheaper though.

I've also researched the size of the WX10 on Honda's website. Found it isn't huge, its roughly a 12 inch cube. Probably not much bigger than an electric pump.

Hadn't realised that lay-flat hose might kink and stifle the flow. Think I'll try one out and be prepared to stow a few metres of rigid hose if lay-flat doesn't work.

In case anyone is thinking on these lines, I came across one electric pump specifically designed for salt water - this one:
http://www.machinemart.co.uk/shop/product/details/csw1a-saltwater-pump That is £100 or so. If it was only for emergency use, I'd probably get a cheaper non-seawater one.

 

[mattnj]

Thanks all, some good points I hadn't thought of there.

The dodginess of a running a genny and 240v on a sinking ship had occurred though. I agree with the reservations but thought it would be a useful last resort when desperate. I'd put the genny in the sheltered part of our cockpit, under the hardtop bit. And assume that the pump does what it says on the tin - "submersible" with watertight electricals.

Hadn't realised that the £350 Honda WX10 weighs only 6kg. That's tiny - half the weight of my Tohatsu 3.5 2-stroke outboard! and only 2kg heavier than an equivalent (140 l/min) 240v submersibles. That takes away the weight advantage that I thought electric would have. Electric is still much cheaper though.

I've also researched the size of the WX10 on Honda's website. Found it isn't huge, its roughly a 12 inch cube. Probably not much bigger than an electric pump.

Hadn't realised that lay-flat hose might kink and stifle the flow. Think I'll try one out and be prepared to stow a few metres of rigid hose if lay-flat doesn't work.

In case anyone is thinking on these lines, I came across one electric pump specifically designed for salt water - this one:
http://www.machinemart.co.uk/shop/product/details/csw1a-saltwater-pump That is £100 or so. If it was only for emergency use, I'd probably get a cheaper non-seawater one.

yes, the wx10 is tiny and light, i got mine, secondhand a while back on eBay for £120, think thats the best option.