Automatic bilge pump

Amcarrapatoso · 28 July 2013, 08:31

I have a 5.20 m Valiant Rib with a bilge pump (non automatic).
It it rains and the boat is not covered, the aft almost sinks.
I am thinking installing a second bilge pump, with automatic switch, maybe a "removable" solution, just to avoid this situation.
Any comments? Any pump model recommended.
Thanks

ShinyShoe · 28 July 2013, 08:36

Why not just fit a float switch to the pump circuits? Only advantage I can see to a second pump is redundancy if one fails. But I'd say an elephant trunk or something simillar would be a better redundancy option when out of the water and a bucket for if you are stationary.

jambo · 28 July 2013, 08:46

Quote:

Originally Posted by ShinyShoe

Why not just fit a float switch to the pump circuits? Only advantage I can see to a second pump is redundancy if one fails. But I'd say an elephant trunk or something simillar would be a better redundancy option when out of the water and a bucket for if you are stationary.

Would second that. I am on a swing mooring for six months and use a float switch.

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ribber · 28 July 2013, 08:54

Replace it with one of these

RULE-MATE FULLY AUTOMATIC BILGE PUMP 500 GPH 12V - Rule Electric Bilge Pumps - RULE-MATE FULLY AUTOMATIC BILGE PUMP 500 GPH 12V - Rule Electric Bilge Pumps - Discount Marine Chandlery and Sailing Equipment. Bargain Boat Spares and Clothing

ShinyShoe · 28 July 2013, 08:59

Or one of these:
RULE-A-MATIC FLOAT SWITCH - Float Switches - RULE-A-MATIC FLOAT SWITCH - Float Switches - Discount Marine Chandlery and Sailing Equipment. Bargain Boat Spares and Clothing
Available elsewhere (fleabay etc) for half the price, and save £30 for the next bit of kit..
Doesn't sound like there is anything wrong with his pump

Nos4r2 · 28 July 2013, 09:48

Personally I'd prefer to add a float switch-pumps and switches don't usually fail at the same time and replacing both is more money.

Amcarrapatoso · 28 July 2013, 09:51

Thank you all.
I will try the switch option (or the automatic Rule pump).
The transom of the Valiant PT-520 is very low and the Suzuki DF 90 is heavy. Already had some situations where the transom was below water level (after one night of heavy rain). I was lucky the engine started and could drain the water by driving at slow speed.

ShinyShoe · 28 July 2013, 09:56

Bear in mind the pump if its got that much water to shift will drain a fair bit of power. You'll want a different battery or you wont be able to start the DF90...

Cover?

Amcarrapatoso · 28 July 2013, 10:06

If I leave the boat on the water for a long time, I will use the cover, but just for one or two days...

Thanks for the note about the battery capacity.

DGR · 07 August 2013, 15:55

I use Rule 800 gph auto pumps on mine - they switch on for a second every few minutes, and switch off again if there is no resistance (i.e. no water).

However - left on the mooring for a month last autumn (for reasons I had no control over

) - two pumps completely flattened the batteries on the boat...

hadd · 07 August 2013, 20:22

Quote:

Originally Posted by Amcarrapatoso

If I leave the boat on the water for a long time, I will use the cover, but just for one or two days...

Thanks for the note about the battery capacity.

I fitted one of these last year great little pump i put mine on a switch so it can be turned off when the boat is not in use it kept the boat dry the last time i left the boat on mooring over a few days & night at Oban

RULE 500 12v Bilge Pump 25S - FULLY AUTOMATIC - | eBay

Amcarrapatoso · 08 August 2013, 14:51

Some automatic pumps have built-in switches, others start every few minutes to check if there is water.
Any comments on pros and cons of the two approaches? Reliability, battery usage?

DGR · 08 August 2013, 15:07

The ones with the built in switches tend to be bigger to house the float switch, but will only pump when there is water present - so won't drain your battery on 'standby' (unless it's raining/seawater getting in so it's pumping anyway).

The electronic auto ones that switch on every couple of minutes to see if there is any resistance (i.e. water to pump) tend to be smaller, but can drain your batteries, even if it's been dry, if left for a sustained period.

I like the electronic auto ones - they take up much less space - even if it did flatten my battery once.

Edit about reliability - all 4 of mine are the electronic (no float switch) Rule 800 gph auto pumps, 2 are 8 years old, 1 is about 3 years old, and 1 has been on the boat for about a week. The ones that needed replacement are the deck pumps - so get used more than the two in the engine box.

D...

jambo · 08 August 2013, 17:53

I have answered this thread before. But I must advise that I had two rule matics and they both ran my bats down and did not last a season. Went back to a rule 1100 and float switch plus the best set up IMO

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SimonCh · 08 August 2013, 18:44

with a float switch, approx how much pumping are we talking to kill a battery?

PeterM · 08 August 2013, 18:49

Rule auto lasted six years. Ran the bat down once, but I had two batteries. Loved it..very simple.

ShinyShoe · 08 August 2013, 20:28

Quote:

Originally Posted by SimonCh

with a float switch, approx how much pumping are we talking to kill a battery?

Depends on your pump and your battery.

Assumptions: small pump like this: RULE BILGE PUMP 500 GPH 12V - Rule Electric Bilge Pumps - RULE BILGE PUMP 500 GPH 12V - Rule Electric Bilge Pumps - Discount Marine Chandlery and Sailing Equipment. Bargain Boat Spares and Clothing
Will pump 500 gal/h
Draws 2.1A
You'll probably find starting draws more power and pumps less so if on and off a lot then it may be less.
So if you have a 100Ah battery you can only really run it it to about 40% of that before the voltage drops too low. So you have about 60Ah. That means you've got less than 30hours of pumping. Then depends how much water you are shipping. A big wave would easily be the quivalent of chucking a gallon bucket at you. Will depend on the hull and where you are moored etc. If that happened every minute you'd be shipping 60gal an hour. So you'd probably be pumping for 9minutes in every hour. So you'd keep pumping from a fully charged battery for 200 hours at that rate... So just over a week. And thats not in a major storm...

If there were no waves or leaks and just rain.... Assuming you have a 6m Rib x 2m Wide so have a 12msq (120,000 sq cm) free surface. Last year we had an average of ~1300mm rain. 1mm of rainfall is 1litre over a msq. So 1300mm is 1300litres per metre, so 15,600litres over the boat --> ~ 4000 gallons So I don't think there is a major problem with rain alone... Even if you had a months rain in a day you'd get 400gallons so only an hour of pump running which would only use 2Ah of battery...

SimonCh · 09 August 2013, 19:27

Quote:

Originally Posted by ShinyShoe

Depends on your pump and your battery.

Assumptions: small pump like this: RULE BILGE PUMP 500 GPH 12V - Rule Electric Bilge Pumps - RULE BILGE PUMP 500 GPH 12V - Rule Electric Bilge Pumps - Discount Marine Chandlery and Sailing Equipment. Bargain Boat Spares and Clothing
Will pump 500 gal/h
Draws 2.1A
You'll probably find starting draws more power and pumps less so if on and off a lot then it may be less.
So if you have a 100Ah battery you can only really run it it to about 40% of that before the voltage drops too low. So you have about 60Ah. That means you've got less than 30hours of pumping. Then depends how much water you are shipping. A big wave would easily be the quivalent of chucking a gallon bucket at you. Will depend on the hull and where you are moored etc. If that happened every minute you'd be shipping 60gal an hour. So you'd probably be pumping for 9minutes in every hour. So you'd keep pumping from a fully charged battery for 200 hours at that rate... So just over a week. And thats not in a major storm...

If there were no waves or leaks and just rain.... Assuming you have a 6m Rib x 2m Wide so have a 12msq (120,000 sq cm) free surface. Last year we had an average of ~1300mm rain. 1mm of rainfall is 1litre over a msq. So 1300mm is 1300litres per metre, so 15,600litres over the boat --> ~ 4000 gallons So I don't think there is a major problem with rain alone... Even if you had a months rain in a day you'd get 400gallons so only an hour of pump running which would only use 2Ah of battery...

Wow, wasnt expecting that! great answer, thanks very much!

ajstars · 11 August 2013, 00:18

Anyone tried the Water Witch electronic switch?

Looks to be promising from the description and it is used on lots of foreign rescue boats so I guess it is well thought of. Plus it can be easily added to an existing pump.

BumbleAbout · 11 August 2013, 20:09

No - but I changed a float switch which lasted a season for the Whale sensor switch (no moving parts) and it has been very reliable so far ...