Bob Tidy

Now then Interesting document, The prop calculator https://www.vicprop.com/ document earlier in the thread says "Failing this, you can reduce the diameter and increase the pitch at the expense of your propeller efficiency. The rule of thumb is 1 inch of diameter is equal to 1 1/2 to 2 inches of pitch". therefore the opposite must apply ie increase the dia and reduce the pitch to achieve the correct loading. This leaves me with approximately the correct prop once you allow for the large alternator we are driving. If we hit a tough patch or have a bit on the prop whilst the Alternator is bulk charging, we get black smoke and a slow increase in revs when opening her up, but it,s fine with a clear prop and a bit of water. Pity we can't have access to a dock and a selection of props when theses decisions are being made.

Now then I would hazard a guess that a 27x25 would be fine on an empty boat, and be able to cruise at tic over, possibly a bit fast into locks and prop walk for England though. Big props are great for getting a grip on the water (including stopping), but when loaded/towing/dragging through the mud, the engine needs to get enough revs on to create the power otherwise it will bog down smoke for England and knock. I wouldn't buy a car that was so over geared it couldn't hold top into a head wind, but at least in a car you can then change down. A 24x17 will have the same theoretical speed as a 27x17 but less grip on the water (not good for stopping) which could cause you to go slower, or achieve higher revs and possibly go faster , however Battersea will pull max revs in decent water. Using a turn to much throttle in a restricted channel sucks you onto the bottom and looses about 1mph per turn as measured with a navigation app If you permanently run empty, don't tow or go onto narrow/shallow canals then a 27x25 might be fine. On 16-8-18 Battersea should be leaving Great Haywood going to Gayton Junction she is trimmed to approximately a 10 ton load, unless they have dredged the bit after Fradley since I last passed, it provides a good demo of why I don't run a bigger pitch. We aim to leave the war weekend at Stoke Bruerne Sunday 9th Sept in the evening heading back to the Caulden you are welcome to have a go on either trip. I believe the only practical answer is to try as many working boats with a National or RN and go with whatever you feel is right for you. Happy hunting Bob Tidy

Now then Battersea is running a National with Bruntons 2/1 box and a 27" x 17" Loaded and towing a 16" pitch was recommended to me, my experience is that with deep water we could pull more pitch however this one is enough at times when running shallow bits of the cut along with modern alternators. I would recommend as big a prop (Diameter) as is safe to fit as you get more grip and stopping power, be very cautious of trading smaller diameter for more pitch cos you will get more prop walk. you are welcome to come and try ours or get together to compare, feel free to get in touch. Bob Tidy

True, current balasting is about half way down from Empty so I suppose I have a choice, Top clearly works ok now the strainer isn't flat so more than 4 holes can work and the bottom valve opens fully with pipes not blocked by the remains of something long dead. I will try the bottom next trip on my way round to the Audlem gathering and see how it goes.

Interesting you are to far down to get blocked, we were in dock at backend of last year and reinstated, cleaned/overhauled the bottom pipes and valve on Battersea intending to use it as a backup, and reshaped the sieve on the top intake. On the way back to the mooring the top intake didn't block (well it wont now we have a 2nd option ) but the lower one did remain clear when i checked it, I thought it would get full of dead leaves/mud off the bottom. I would be interested to know which one others use and their views, possibly I should run the bottom with the top as reserve, at least i can reach it from the lockside with my shirt sleeve well rolled up.

Hi all Just a thought as stationary engines they were cooled by a large tank, the quote is "should not exceed 130 t0 140 deg F (55 to 60 deg C)" Ideal temperature is not quoted, RN may have view on this but we are dealing with a variation on a Mk1 RN and the RN design has been improved over the years all RNs are not equal My personal preference is to use raw water directly (with a tap to restrict the flow if required), using a thermostat is fine if the spare water then continues overboard without going through the engine. I would be concerned if a thermostat system results in no water exiting overboard until operating temperature is reached. My reasoning for all the pump is able to provide to go overboard is:- by being able to visually monitor the output you can then identify if the inlet strainer is becoming clogged before you start to overheat. A temperature check by hand is always available. You can check for a good flow when entering a lock when it is easy to clear the strainer with the screwdriver kept in the ticket drawer for the job Given the choice I would have an inlet on both sides of the boat because when the mop fails to clear the leaves etc the towpath is without fail on the wrong side and at 6ft 1in tall the strainer is way out of my reach from a town class engine hole door. Having a tap gives the ability to remove the restriction when things start to warm up however running into a shallow stretch causes a noticeable rise in temperature with or without a bit of rubbish on the strainer all taken care of by the spare cooling capacity, Battersea never overheats unless the outflow has dropped to a trickle, when its getting dark you can hear the outflow splashing back into the canal, very reassuring. Battersea runs without restriction and maintains an exit temperature that is pleasantly warm until the strainer starts to clog when it can soon reach as hot as you can keep your hand in, if the mop fails (never a bridge when you want one) it will soon start to steam, which running old cars in my youth always seemed to cause the thermostat to fail. Keep things simple works for me.

Now then The "Instructions for Erection and maintenance of national "D" series engines" says "The temperature of water as it leaves the engine should not exceed 130 t0 140 deg F (55 to 60 deg C) at which temperature it should just be possible for the hand to be held on the outlet water pipe." The oil cooler as per your diagram is a good idea, if my inlet blocks causing an overheat the water temp soon comes down once flowing properly however the oil pressure at idle remains lower than before not really recovering until the engine has been stopped for some time and the heat dissipated. Hope this helps Bob Tidy

I know its an old thread, however people use them to research. Little ends are fed oil up the hollow conrods.

Blow off pressure in the book is 1750 lbs per sq inch or 123 kg per sq cm. It is well worth getting them set accurately, I bought a tester cheap from the internet and now start on 2 cylinders. https://youtu.be/6NbPN91plIE Is worth a look for anyone new to injectors, if the injector pump is in good condition with the injectors out but connected you can see the pattern and turning the engine slowly get an indication of a dribbling injector. Warning for anyone new to this 1750 lbs will inject diesel straight under your skin! If things are near to being running and it is cold, a hair dryer, hot air gun or blow lamp (in order of risk) across the air intake manifold with the filter removed will often be enough to get her to fire. If compression is a bit low a squirt of oil into the cylinders will often increase the seal on the rings for a few turns. Swapping an injector from a running engine (or borrowing someone's spare) would prove whether it is the injector or not, it is a pity you are not nearer! I don't know who could check you blow off pressures in your area but they will need to be set for the engine to run at its best, the time it takes the pump to get to blow off will I believe vary with the pressure and effect the timing, I had a lazy cylinder until I set mine, you could currently have two!

Hi The pump arms can be swapped

Tony and Paul Redshaw stock the service kits and may have the part you require, you will need a photo though cos there are several variations. The lever is transferable to a new body if you have to go down that route with modifications to your pipework. Unit 13, Riley Close. Royal Oak Ind Est NN11 8QT Daventry, Northamptonshire 01327 700219

Now then. I have a small gear to copy from which is better than yours, where are you moored? I will look for it in the morning and take a picture. All best Bob

Hi Only you can tell if the oil filter has been bypassed, by following the pipework. As i said before there is a stud and lock nut on the side of the rotary self cleaning filter which is the adjustable pressure relief valve, exess oil returnes to the sump though the crankcase door. however some pumps also have this valve. Assuming the filter has been by passed for a modern (better) one, you must have the pump with the valve Bob

Just as long as the rockers are getting a little oil they should be fine. Bob

Sounds like you have a remote oil tank, and therefor a 2 part oil pump and dry sump. The object you pictured is a self cleaning oil filter, I have several spare ones. inside is a series of plates the oil has to force through them leaving the particles behind. turning the handle moves alternate plates, the particles gather in a clump and fall to the bottom of the housing. I have some info filed away somewhere, Bob