Of Bilge Pumps and Float Switches......serious...

[boatone]

Been a bit of banter with rumtigger re floatswitches but actually got me into some serious thinking re this whole issue.

Bilge pumps can be activated automatically or manually for two main reasons....
1. Routine removal of minor water....sterntube drip etc
2. In anger cos exceptional inflow of water in an emergency

If a float switch is fitted they will operate automatically and in situation 1 cut off again. Howver in situation 2 the bilge pump may be unable to cope with the inflow and the boat will be at risk of sinking. In both cases without some sort of additional alarm you may be unaware that the bilge pump has actually cut in. If the boat is in the marina and connected to shore power the pump may operate indefinitely but on battery power will eventually run down the batteries and stop.

Had a situation in my marina recently where by pure chance someone noticed a neighbours boat low in water and could hear pump running and just managed to avoid sinking due to ruptured skin fitting.

So heres an idea for debate.............
If boat usually dry inside and only reason float switch likely to trigger because of emergency water ingress then have audible alarm also connected to switch so goes off when pump triggered. If float switch triggers under normal circumstances then fit secondary float switch at higher level which will trigger audio alarm if water reaches that level. Either way audio alarm loud enough to attract attention whether on board or not.

Simple idea but I think it has merit.....What say you.....?




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[KevB]

Yes, sounds a good idea but forget the buzzer, wire it up to the horn.

I have a float switch and also a manual switch. If the float switch turns the bilge on, the light on the maual switch lights. Not sure I'd notice it on a sunny day though.

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[terryw]

Our boat has 2 pumps. One is at the bottom of the bilge and is Auto/Manual. The second one is about 2 inches higher and is Auto only, but has an alarm which goes off the whole time it is pumping. Seems to solve all your queries.

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[boatone]

Wasn't thinking of a buzzer or lamp tho no reason why couldnt have them as well....something really beefy like horn or screecher. No doubt someone will say might annoy neighbours but bloody good thing too I think...../forums/images/icons/laugh.gif
Actually could also trigger flashing strobe light......

Seriously....should be good for a few bob off the insurance premiums dontcha think?

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[boatone]

Well done but was it standard fit?
Also, is alarm loud enough to wake the neighbours?

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[Its_Only_Money]

Re: Of Bilge Pumps and Float Switches......serious

Sure - my water-in-bilge alarm is seperate to (and lower than) the float switch. This is because the boat is dry-berthed so any water in the bilge warrants investigation - but I can't mount the float switch or pump any lower.

You could mod a float switch/alarm system for a boat left afloat with a selector switch to select loudish audible buzzer when onboard and hugely loud marina-wide klaxon when unattended.

I would mod your last suggestion though by adding a second pump along with the second switch, my reasoning is that for the second switch to trigger it means there is water to that level coming in at a rate that has already overwhelmed the first pumps ability to remove it, so this indication is a good one that your boat is sinking quite fast! Of course this second switch needs connecting to a klaxon or similar as you haven't got long for the problem to be dealt with before your pride and joy goes under.

<hr width=100% size=1>Rgds

Simon
Its Only Money
Fairline Sprint
Solent-based

 

[terryw]

Yes it was standard fit, and it is load enough to be bl**dy annoying when travelling at 25 knots (not as serious as it might appear), so I would guess that at night it would be heard.

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[KevB]

Re: Of Bilge Pumps and Float Switches......serious

I think I'd want to know why the first pump is going, not wait for the second to start before being alerted.

Still not seen someone come up with the retro fit engine pump as suggested by TCM some years back. Something to convert 460bhp of V*&v* power into an emergency water pump.

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[boatone]

Re: Of Bilge Pumps and Float Switches......serious

I had a Yanmar (YE10?) diesel on a raggie boat once that was fitted with a Y changeover valve on the raw water intake side so could switch it between sucking bilges or direct intake. Brilliant it was. Something like that could be fitted with an electrically operated changeover valve I think?

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[boatone]

Re: Of Bilge Pumps and Float Switches......serious

<blockquote><font size=1>In reply to:</font><hr>

You could mod a float switch/alarm system for a boat left afloat with a selector switch to select loudish audible buzzer when onboard and hugely loud marina-wide klaxon when unattended.

<hr></blockquote>

Cant see point of that ..more cost and and could easily forget to switch over between alarm levels......if it means trouble blast it loud and wide ASAP.


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[Its_Only_Money]

Re: Of Bilge Pumps and Float Switches......serious

"Still not seen someone come up with the retro fit engine pump as suggested by TCM some years back. Something to convert 460bhp of V*&v* power into an emergency water pump."

I would have thought straightforward, just have a Y connector in the raw water pickup with a second seacock pipe/strainer in the bilge, as required open bilge seacock then shut "sea" seacock and the engine will draw its cooling water from the bilge. Select appropriate throttle setting and away you go. To reverse (while there is still water in the bilge), open the "sea" seacock and then close the bilge seacock so the pump will never run dry.

Bit of a manual process I'll give you but a big label close to the bilge seacock that reads "Emergency Bilge Evacuation Only. Open BEFORE Closing Raw Water Seacock, Open Raw water seacock BEFORE closing" should do the trick. I'd even go so far as to wire the bilge seacock shut and have some wire cutters on a lanyard close by, maybe seacock and wire cutters mounted in a red box which alarms when opened.....

I have tested this theory in reverse when a cooling hose blew on my engine, the raw water pump appeared capable of filling the bilge quite efficiently!

To have sonmething that could actually use the output power of the engine you'd need a proper centrifugal pump mounted off the nose of the engine, maybe the fire pump off a Green Goddess perhaps????

<hr width=100% size=1>Rgds

Simon
Its Only Money
Fairline Sprint
Solent-based

 

[Its_Only_Money]

Re: Of Bilge Pumps and Float Switches......serious

Good point but I find with my crew I need just enough of a warning to cause the necessary investigation...and it let's you fit a really BIG klaxon as you know you should never be next to it when it goes off....also if you are going under then the CG need to be able to hear your mayday over the alarm noise!

Wouldn't take long to get into a "Klaxons to manual and cross-check" type routine on leaving the boat...

Of course you could take it all the way and have aircraft style spoken warnings broadcast throughout the boat, imagine (in a Joanna Lumley type voice): " Wake the skipper, the boat is sinking....Wake the skipper, the boat is sinking....Wake the skipper, the boat is sinking...." of course at some point the boat will become self-aware a la 2001 /forums/images/icons/smile.gif

Worth noting that apparantly visual warnings are the easiest for us to mentally ignore even if we have seen it, audio are less easy to ignore and combination audio/physical the hardest (eg a stick-shaker stall warning on an aircraft).

<hr width=100% size=1>Rgds

Simon
Its Only Money
Fairline Sprint
Solent-based

 

[halcyon]

But this is history, the helm panels we supplied Sealine from around 89 to 96 all had engine bilge pump alarms, that came on with pump running. Also all the pumps had manual or auto operation. To-day we supply them with a unit for the larger fly bridge boats that monitors 4 bilge pumps and sounds an alarm at lower and upper helm stations with a built in delay.
The problem is that the other manufacturers have not followed Sealines lead for customer care.
Same with all things marine takes years to filter through.

Brian

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[boatone]

Thats great but I think you are missing my point.
What is different here is that the alarm would be triggered by a 'serious' condition rather than a routine one. Many boats have bilge pumps which routinely kick in to remove 'normal' water ingress due to stern gland etc. You would not really need an alarm under those conditions although a dash mounted indication that the pump was running would be 'nice to have'.

The idea of a secondary switched circuit indicating that there is an ABNORMAL bilge pump operating condition is what I am advocating....and I am not for one moment suggesting that it hasn't been thought of before.

I have had enough boats and know enough other people with boats to know that it is not a common configuration. In fact many boats seem to have woefully inadequate bilge pump/alarm installations of any colour.

Having just re-read your post carefully I presume that it is the 'built in delay' feature that meets my objectives?


<hr width=100% size=1><A target="_blank" HREF=http://www.boatsontheweb.com/> Website, Photo Gallery, Chat Room, Burgees</A><P ID="edit"><FONT SIZE=-1>Edited by boatone on 22/11/2004 13:43 (server time).</FONT></P>

 

[Its_Only_Money]

Re: Of Bilge Pumps and Float Switches......serious

Maybe history but I doubt whether Fairline are going to come along and retrofit their current bilge pump alarm system to my boat, let alone Sealine and their version.....hence the need to discuss it regularly to achieve it "filtering through"....so us on older boats with such an interest can adopt the latest and greatest ideas.

<hr width=100% size=1>Rgds

Simon
Its Only Money
Fairline Sprint
Solent-based

 

[andy_wilson]

I can\'t see YOUR point!

If the primary bilge pump can't cope, why not have a secondary to come on automatically when the higher float level is activated.

By the time you have installed a secondary sensor it would be a piece of cake to add a secondary pump in too.

Why just have it sounding an alarm to tell you that the boat is about to sink, when it could have already started the pumping process before you get the VHF / angry buckets / beaching legs / life jackets out?

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[jfm]

B1 you miss halcyon's point. Many boats (Fairlines since at least 1999, and Sealine as per halcyon) have a hooter that only cuts in after the pump has been running for a set time, about 30 seconds. Ordinary clearance of sterntube drip takes less time than that, so hooter doesn't sound. but if there is serious coindition and pump cannot keep up, then after 30 seconds running the hooter sounds . Fairline have this hooter and dashboard red light at both helms on their flybridges, have done for years. There's also an LED panel on larger boats to tell you which pump is sounding the alarm

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[boatone]

If you read tale end of my last post you'll see I did recognise that.

If some manufacturers are already doing something like this thats great. I suppose my real point is that this is something thats actually quite easy to retrofit on ANY boat so why not start thinking that way? The instances I've come across where it would have helped have all been older boats (not that surprising in terms of wear and tear failure).

andy_wilson's point is well taken re why not have a second pump as well........much will also depend on what battery power is available as to how much time you have to react.

Also be interesting to ask how many boats fitted with intruder alarms have half way decent bilge pump arrangements?

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[mjf]

Princess do this too - except that I reckon the buzzer going off on the flybridge really ought to be a hooter with a visual beacon thingy too. Would only do this say when the ignitions are off ie boat not being actively navigated - to warn marina security chaps or indeed yourself when away from boat at anchor that she about to sink!

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[brianrunyard]

Then a third float switch, that operates just before boat sinks, to fax claim form to insurance company.


<hr width=100% size=1>Brian
http://homepage.ntlworld.com/brunyard