chieftiff

In marine applications bilge pumps are always fitted with what's termed a riser loop (sometimes called a venting loop) which ensures that syphoning can theoretically never take place, many people also fit non-return valves but there is a school of thought that says non-return valves are prone to failure or blockage and can be the seat of many problems, that said the risk of syphoning at sea is significantly higher than it is on a canal. Rule don't differentiate and recommend the fitting of a riser loop in all of their bilge pump installations regardless of where the outlet is. There are plenty of articles about the correct fitment of bilge pumps but most like this one refer to marine craft: http://www.yachtsurvey.com/bilge_pumps.htm

Crudely speaking all non protected centrifugal type pumps can allow back syphoning, just to confuse the non-engineering types centrifugal pumps have an impeller and the terms are often used interchangeably but an impeller type pump can be something else like a propellor pump which isn't centrifugal but does have an (propellor shaped) impeller. This type of pump (impeller or centrifugal) is used in situations when the pump isn't needed to create pressure (pressure being resistance to flow) ie they are used to move fluids from one place to another normally two places at atmospheric pressure. In order to create pressure the pump either needs to be of a different design such as a variable swashplate pump (or one of many others) or it needs to have a non-return valve fitted at the outlet. If there is any danger of a syphon being created on shutoff (when the mass of fluid in the inlet pipe is drawn by gravity to create a partial vacuum in the inlet) a non-return valve can be fitted but you need to be careful as they can create resistance to flow (pressure) and reduce output or stop flow altogether. A simple flapper valve would be enough to stop back syphoning in this case and probably cost about 30p. Edited because spelling isn't my strong point!

I've seen a couple of narrowboats with these motorhome type units fitted: http://www.mobilegas.co.uk/caravan-camping/air-conditioning/ I haven't got a clue if they are anygood, reliable or even practical over long periods given the drain of 2.4 -7.4 Amps, expensive too.

After initially dismissing electrical systems because I wrongly assumed we were talking about a remote cockpit type installation I think you could go someway with an off the shelf electrical system for less than £500 to "power" the tiller, unfortunately this link doesn't provide much in the way of torque information but there are certainly plenty of systems to choose from. http://atvpowersteering.com/ If they were man enough for the job this idea could be ok, manual reversion in the event of power failure could be built in by design, lots of ifs, coulds and maybes! It would be an interesting project, unfortunately with the way vehicle design is going though it's possible that in 5 or 10 years time when the system needs replacing or repairing you'd have to start from scratch with whatever is on the market at the time so re-bracketing etc maybe necessary. Edited to make the link work.

An EPS system would probably be impractical on a boat although not impossible, most smaller cars with power steering have EPS (electrical power steering) fitted because it's cheap and despite the manufacturers claims that it's better for this reason or that it really does fall down to cost. You'd want to look at a hydraulic system such as this: http://www.nauticexpo.com/prod/jefa/boat-s...040-106389.html which isn't going to be cheap and requires at least a basic level of mechanical engineering knowledge (I'm not suggesting you don't have that just pointing out that this isn't really a DIY option unless you have some basic mechanical knowledge and skills) Hydraulic systems are generally very reliable and relatively easy to maintain coupled with the fact that most hydraulic components are available off the shelf and reasonably standardised like washing machine components, they offer a long term solution as they can be overhauled and repaired without fear that they have become redundant. Edited to add: The link I provided is for a transmission system only and depending on your installation you will only need some of those components, look around the site I linked to and you'll find all the other bits required like a hydraulic pump, servo/ power piston, operating valve etc. Potentially it's a big job but the more I think about it; if you just wanted hydraulic assistance from the tiller it could be fairly simple!

Difficult to tell given the depth and distortion of the snow but almost certainly a rabbit, hare tracks are very similar but the front tracks are usually proportionally wider than the rear tracks, both animals run with a similar gait as opposed to squirrels who appear to hop around but leave 4 distinct prints evenly spread but in similar front to back arrangement. Hare aren't renowned for hopping around slowly and are usually stationary or running - rarely anything in between, whereas rabbits amble around picking at bark and twigs this time of year with a nibble at grass when they can get to it, so the short spacing of 30cm also suggests rabbit, a hare would generally be further apart and the track spread. Rabbits are also far more common than hare so would I have to put a bet on it the odds are in favour of a bunny. The other print is a well melted and spread (making it look larger than it was) common dog, you can see the nail arrangement which you wouldn't see in a large cat, odds on again of course unless you took the photo at Longleat in which case I suggest you get back in the car! Yours Davy Crocket king of the wild frontier and renowned tracker

I have a Garmin etrex legend HCx which I use on a handlebar mount for mountainbiking, and keep in my rucksack for emergencies (ie getting really lost when the fog comes on the Glyders, the only time I've actually needed it) when climbing or walking, it's perfect for me. I changed my mapping software from memorymap last year to use: http://www.mapyx.com/ which is excellent in my opinion especially if you are just starting out as you can cheaply build up your digital maps by buying tiles (essentially 1:50000 or 1:25000 OS maps) one at a time or buy the lot on one of their special offers. It's great for planning rides/ walks and climbs as it has more functionality than memorymap but on the ground there is no real difference.

Not quite! I was also a mechanician having joined as a mechanic and reached the dizzy heights of PO before artificers course, "Chief Mechanician RN (rtd)" would have looked like a conundrum above my avatar space! But that's off topic Perhaps you didn't mean it to be patronising but I assure you I read it as such and it appears that the poster did too from his reaction.

I recently had this problem with my work laptop, took it to the IT guy at work who put the office cleaner's vacuum hose up to each of the vents under and on the side with the laptop switched off........ problem solved seriously it took 2 minutes, the amount of dust and hair (dog, daughter, wife.... I don't have any) that becamse evident at the outlet grill was incredible. Worth a try just make sure the laptop is off!