Adding a Deck-mounted Switch to the Attwood Waterbuster Pump [40]

By Nick Gill

There have been a number of pump discussions in the NSWSKC newsletter. The Attwood Waterbuster (WB) has been among those listed as used by sea kayakers. It costs around $100 from marine shops. The WB is a submersible 200gph (US gallons per hour — about 700 litres per hour) pump powered by three ‘D’ cell batteries. Attwood claims 5-hour operation with alkaline batteries. I have been told of a Victorian paddler who has found a rechargeable 6V battery that works with the pump and fits in the battery compartment. The main advantage of this pump is that it is self-contained. The batteries are housed within the waterproof pump housing itself. This makes it a relatively simple affair in comparison to the l2V marine pumps.

The main disadvantages of the WB are its low output relative to a 12V pump and its switch. The most popular l2V pump is a 500GPH pump. I have also heard of an 1100gph pump being used in sea kayaks. This larger pump draws more power when it operates but pumps proportionately more water for a given power draw. I’m not sure why it’s not in wider use. Perhaps someone can enlighten me. The WB pumps 200GPH. This is much lower the 12V pumps but the amount pumped from a sea kayak is relatively small. This morning I filled my cockpit with water equivalent to the amount I get from a wet exit. The WB took just under five minutes to pump the water out. This seems reasonable to me given the complete lack of effort required.

The WB has a waterproof pushbutton switch on the pump body. This is not adequate for sea kayak use, which requires a deck-mounted switch for operation with the sprayskirt on. There are some alternatives to a deck-mounted switch. These include float switches that automate pump operation when the water reaches a level that activates the switch. I haven’t seen these used in sea kayaks (but maybe someone out there uses them). The other option is the switchless, automatic pumps. Rule makes two types. One is their computerised ‘Platinum’ series. These pumps check for water at regular intervals, pumping if water is detected. They draw power to conduct the checks. Rule claims a draw of 0.25 ampere-hours per day for the 500gph pump. They also make a ‘Rule-mate’ series with a built-in float switch. These require 2 1/8 inches (55mm) of water to operate. Too much for a sea kayak, I suspect. If anyone has tried these automatic pumps I’d be interested to hear from them.

The remainder of this article is about modifying the WB for use with a deck- mounted switch.

Attaching an External Switch to the Waterbuster

Anyway, I had a WB and didn’t feel like spending more money. I modified it as follows. One of my principles was to mount everything in the cockpit, avoiding drilling holes in my rear compartment. First I needed a switch. Initially I thought a pushbutton switch would be most desirable; low profile and relatively robust compared to a toggle switch. However, I had trouble locating a waterproof pushbutton switch. I did think of various ways of sealing existing pushbutton switches such as painting them with marine varnish or Sikaflex. I could have used the switch from the WB but Attwood will not supply the switch alone and I expect to have to replace the switch. I have since written to Judco, the WB switch manufacturer in California. I haven’t heard back but it all seemed a bit complicated. Eventually I went for a readily available and off-the-shelf waterproof toggle switch from Dick Smith Electronics ($11.95, catalogue no. P-7664), as used by the redoubtable Tasmanians and others.

I unscrewed the switch from the WB and removed it. This left a hole in the pump body. I also removed the battery housing. At an auto shop I purchased a packet of 3/8 inch blanking grommets. With coarse sandpaper I roughened the pump body inside and out around the hole. This was to provide a better surface for Sikaflex adherence. I fitted one to the hole in the pump body and pierced it with a hot nail. This provided a snug hole through which to later insert the wires running off the switch.

I then soldered insulated electrical wire to the wires on the waterproof switch. Over the joins I smeared Araldite. Once dry I put heat shrink over the join and then smeared Sikaflex over the whole lot. I then put some larger heat shrink over both wires to bring them neatly together. I then cut the wire to length and inserted it through the hole in the blanking grommet.

If you don’t have soldering equipment don’t buy it. Buy crimping connectors and join the wires using these. You can even buy “waterproof” ones from marine shops. I’d still heat shrink/Sikaflex them though. In fact the waterproofing seems to come from heat shrink which is integral to the connectors.

Now I had to connect female spade connectors to the end of the wires. These then connect to the male connectors on the pump. The WB has different sized spade connections to rule out incorrect wiring when replacing batteries. You will need some 4.8 mm and 3mm female spade connectors. I am going on memory here for sizes; I threw out the packets. The sizes needed are, however, standard so you will have no trouble getting what you need. Take the original WB switch to show to sales staff if in doubt. If possible get insulated connectors. They are easier to attach to the wires, especially if you have a crimping/ wire-stripping tool. Such a tool makes this sort of small-scale electrical work much easier. You can get cheap ones for about $12-$20 from electronics stores.

Crimp the connectors onto the wires, put the batteries back in, and attach the switch wires to the appropriate points in the pump — this is obvious — just have a look at the connection setup prior to undertaking this job. Check that the pump works by turning the switch to “on”.

Assuming the pump works, take out the battery housing again and get the connectors and wire adjusted to a good fit. Then take some Sikaflex on the tip of a nail and smear it around the inside of the lip of the grommet. You can use a nail to raise its edges. Then generously smear Sikaflex around where the wire passes through the grommet. Do this on the inside and the outside of the pump. On the inside be careful not smear so much that the battery housing won’t go back into the pump. Allow this to dry .It might be worth smearing Araldite over the wire/grommet join first to provide some strength. I’m not sure if this is better than the flexibility of sikaflex alone or not.

The battery compartment can then be placed in the pump and the pump lid replaced. You now have a WB with an external switch. It now needs to be installed. You will need to devise some sort of mounting system suitable for your boat. I use shaped foam to place the pump and use shock cord (and olive cleats) run through ‘P’ clips (an electrical cable fitting available from marine and electrical suppliers) to hold it in place. The ‘P’ clips are bolted to my hull and rear bulkhead. Having removed the metal base plate, I have also shaped the base of the WB to fit my hull shape using a Stanley Surform tool.

Drill a hole in the deck where you want the switch. Drill a hole slightly smaller than the switch thread to get a nice snug fit as you insert it. Smear Sikaflex over the top of the switch, at the base of the thread and, from below, insert it into the drilled hole. Then smear a little Sikaflex on the base of the toggle ‘boot’ and screw it onto the switch. The supplied boot has a round base. Dick Smith Electronics also sell a boot with a hexagonal base that can be tightened (carefully) with a spanner or socket. I bought one of these for a couple of dollars, keeping the original as a spare. Even flasher are the military spec boots from Farnell electronics (www.farnell. com, choose ‘Australia’; Sydney 02 9645 8888) which are high quality rubber/silicone of some sort and have a metal hex nut in the base ($10.20, $7 p&h). I haven’t bought one but as far as I can make out you want the boot with 15/32 inch diameter thread -catalogue no. 146-843. They also sell milspec pushbutton boots. I have seen one of these milspec pushbutton boots and they certainly seem to be of more robust. material than the standard boots. Farnell claims salt, weather and UV resistance for these boots. Such boots may be worth it as I have been told the standard boots need replacing regularly.

I wanted to protect the switch. I didn’t have a stainless steel stirrup big enough to go over he toggle but I had some black foam. I shaped a ‘doughnut’ to go around the switch but thought it too bulky and ugly on my red boat with fashionable black fitout. Dave Winkworth suggested a black plastic stirrup used for securing garden irrigation hose. At my local garden centre I found one for 25c. They seemed to come in two sizes. The smaller one won’t fit over the toggle. This is about to be put on my boat using some 3/16 stainless steel screws and nyloc nuts that I had. I’ll use an 11/64 drill bit to drill the holes.

The installation works well so far. Only time will tell if the pump remains sealed.

What You Need

  • waterproof switch (Dick Smith Electronics, catalogue no. P- 7664).
  • insulated electrical cable -3/8″ blanking grommet -spade connectors -sikaflex
  • Araldite or equivalent and Sikaflex marine sealant or equivalent
  • heat shrink -you can buy packets with multiple sizes
  • plastic/stainless steel stirrup and screws/nuts
  • a wire stripper/crimping tool is handy