Tuesday, 23 November 2010

Talking Bilge Again

Earlier this year, I built a Bilge Alarm and blogged about it - "Are We Going Down" (Jan 2010)

Problems like a weeping stern gland, a faulty weed hatch seal and rain water ingress (especially through a cruiser stern decking) can cause you to have water in your engine bilge.

Having once had a weeping stern gland, I used to lie in bed at night mentally visualising the drip-drip into the bilge. Logically, I knew it was a slow drip and the bilge area large and it wouldn't sink us overnight, but it used to bother me all the same.

It wasn't possible to repack the seal straight away (I wasn't confident enough to do it in the water), so I lived with it until the boat came out of the water.

A weed hatch that hasn't been replaced properly or which has a damaged or dislodged neoprene seal, can ship lots of water. Once the thrust of the propeller pressurises the water above it, the weed hatch can spurt water into the bilge at an alarming rate.

I decided an alarm that would sound when the unwanted water reached a certain depth might be a sensible precaution. Then, at least, I might get a peaceful nights sleep.

Looking around on the internet, I struggled to find what I wanted.

So I built my own - the Mk1 model.
It worked well.
Some other boaters were encouraged by what they saw and asked me to build them one, which I did.
That was all nearly a year ago.

Recently, a new group of boating friends asked me if I would build some more.

The problem is that the Mk1 version was very "hand-matic" - each one took me a day to build.

I decided to re-examine the design and see if I could reduce the component build cost and more importantly, remove the intensive labour content.

In parallel to this, I conducted some research to see how many boaters use or see any value in bilge alarms.
I initiated polls on two of the canal forums.
Response was poor on both - few people bothered to reply !!!
However, even with the relatively small sample taken, I was surprised to read that only about 30% of canal boaters had one.

Only about 28% of the sample were interested in having one.

The product description "used" for the purpose of the survey was a brandless bilge alarm that provided visual and audible indication of water in the bilge at a cost of less than £50.

Apparently, it is possible to buy a readymade off-the-shelf unit from Johnson Pumps at £47 (the Johnson Bilge Alert). One disadvantage I can see with this model is that its sounder is VERY loud.

Whats wrong with that, you say ??

Well it's good in one way - if it sounds while your boat is in the marina and you're not, then everybody in the marina will know that your boat has a problem.

However, if it's the middle of the night, your boat is moored to the towpath miles from anywhere and you are onboard, curled up and in the land of nod, a 100dB alarm might actually make you wet yourself in shock...

The other thing is that it is designed to operate at a maximum voltage of 14.4V - some canal boats with wet lead acid batteries have battery charge controllers that output more than this.
I'm sure the 28% and probably many of you reading this, would be quite satisfied with this product, but something stirred restlessly within me.

I quite like the thrill of the chase.

So, I decided to make my Mk2 version.

A couple of things still bothered me though about "soft" or "loud" sounders.

A soft sounder will be fine to wake you from your slumber or even break you out of your trance at the tiller, but if you're not on the boat at the time ???

A very loud alarm will alert the marina, but will it do you any good ??

The occupants of other boats probably wouldn't know what it meant or what to do - do you leave your phone number with every other owner - can you rely on somebody calling you ??

What if you're moored online on 14-day moorings, surrounded by open space or strangers - what then ??

Mmm - dilemma.

So, my decision was to build the Mk2 Bilge Alarm for less than £50 with a soft sounder.

My unit has the ability to work on a voltage range of 10-15VDC and it can be mounted at any depth - some boaters want to know about ANY water and some just want to know when it overcomes their bilge pump.

The added option of a loud switchable 100dB alarm would be an extra £5-10 (could be mounted in the engine bay with an external switch that allows it to be armed when leaving the boat and switched off without marina staff having to enter the boats cabin).

A possible way round the dilemma is to also use an SMS Messaging Unit with the standard "soft" sounder bilge alarm system.

I blogged about this before - "My Boat Just Sent Me a TEXT" - (26th March).

The bilge alarm goes off on the boat, waking you up if you are onboard. If you're not, it triggers the onboard SMS Message Unit, which it is hard-wired to.

The message unit then automatically sends a text to your mobile telling you that the boat is taking on water.

The unit that I have created will not only tell you that the bilge alarm has been activated, by texting you, but it can be connected to one other input such as a burglar alarm and will therefore text you saying a door has been triggered.
So, this is how it works in the boat to boater direction.
It can also be used the other way i.e. boater - boat - it can be asked to remotely switch something on from your mobile.
For example, you can switch your boat fridge on, long before you arrive at the boat.
You can switch your heating on in advance, so the boat is toasty when you get there.
Finally, it can text you and tell you the state of charge of your batteries.
If your batteries have discharged because you have:
- bad electrics
- someone left something on
- your shoreline has tripped on the pontoon, turning your charger off
You will know !!
You will get a text from the boat telling you the exact voltage of your batteries whenever you ask it.
All sounds good doesn't it ?? - we live in an SMS text age.
Unfortunately, this option costs £150 - the price of this technology is not really coming down in monetary terms - the processors just do more and give you more bang for your buck.

Happy pumping.

No comments:

Post a Comment

Note: only a member of this blog may post a comment.