Well, as we reach March 2024, I should jot down some notes on the work being undertaken this winter.
Work done
We made a list of jobs to be done back when we fetched Befur out last autumn. The completed work is shown below in Green, still to be done in Red:
Cleaning the inside of the boiler, removing oil t0 improve efficiency (reduce fuel consumption) –Done – notes and video here
Cleaning the inside of the condenser, for same reasons and improve vacuum – Done – notes with Boiler Work above.
Remachining the LP crosshead and glands as it is now clear that this is the principal source of the hateful knocking the engine makes. – LP Done – see below
Replacing the pump drive worm box, as this is at the point of failure, and adding “assistance springs” to reduce the torque requirements on this box, to extend its probable life! (probably another post here too). – See below
Replumbing the condenser to be “contraflow” as this should improve it’s efficiency too.
Attempting to design and fit a clutch to the prop drive to allow it to freewheel when sailing.
Attention to paint and varnish
Possibly fitting a reinforcing inner fore-deck and removing the anchor chocks and resealing to improve weatherproofing.
Well, as mentioned elsewhere I have found it very hard to make a whistle that sounds nice (in fact one that sounds at all!) … the principal is simple enough, but the practice is much harder with quite fine tolerances and dimensional “magic numbers”.
Making a nicer whistle – version #4 (at least)
I had one noticeable success with a three-chime whistle for the 5″gaugeloco, and the one for the Windermere Kettle is pleasant, but the main whistles for the boat just screech (very loudly, or not at all).
We need a Siren!
This idea has cropped up several times, but finding a set of drawings was hard, and with the “whistle experience” in mind, I really wanted a “guaranteed” design.
Well, as is often the case, the SBA provided an answer via their house magazine Funnel, with an article from 2007 (Issue 112) by Peter Cowie from Auz. This provided the basic idea and design for Befur’s Siren, which I can guarantee works! (Other boaters classify it as “deafening” even from many metres away!)
It does take a fair quantity of steam to set it off, on Befur it’s plumbed in via a 1/4″BSP ball valve and at 200psi that works very well. Here’s a video of it running on air (quietly!)
You should be able to download this article from the link above. I found the drawings provided hard to decipher, so with the drawings in this post and the pictures perhaps all will become clear. You will notice that mine is less shiny, and still awaiting a “trumpet”, there is talk of casting some in bronze!
Drawings
Pete’s original drawing from the Funnel Article
As I noted above the drawings in Funnel are quite hard to interpret (I think there were probably more sheets, which would have made it clear.
However, I decided the simplest approach was to re-draw in viaCAD, so there are links below to a viaCAD file and exported version in .dwg (Autocad file), and .png (graphics picture) file too…
(If you have trouble downloading the drawing files (WordPress doesn’t like them) then just message me (at foot of this post) with your email address and I will send them to you)
These drawings are metric (apart from the threads that are either BSP or TPI threads (because I happened to have the imperial change-wheels fitted to the lathe at the time!!)). The drawings show the components, a sectional GA , listing of the stock materials used to make the siren and a drawing of how the distribution plate was originally drawn (but not how I made it!).
Perhaps the key bit of understanding (which took me a while to spot) was that there is a steam space between the Porting Cylinder and the Body, which is supplied through the spaces in the Distribution Plate and delivers steam to the ports in the Porting Cylinder.
Manufacture
The material for the siren (from M-Machine metals in Darlington and on-line)
The siren is built from phosphor-bronze cored bar, all sourced from M-machine Metals in Darlington.
M-machine will take phone orders and are happy to supply small quantities for home-workshop user. The picture shows the stock used to make the siren, at a total cost of about £75. (in 2023)…
These are stock-sized cored-bar from their catalogue, and the sizes purchased are shown in the drawings I prepared.
The majority of the manufacture is simple lathe work. The larger threads are all screw-cut on the lathe. I usually cut the internal threads first, then cut the male (outside) thread, using the other part as a gauge.
The most challenging parts of the build are the Porting Cylinder and the Rotor.
Rotor
Siren porting cylinder and rotor assembled in the cap.
The Rotor slots are just slots cut vertically (radially) into the rotor with a slot drill, while the rotor is held in a rotary table on the milling machine.
The slots in the rotor can be seen in the photo on the right, inside the porting cylinder.
There are eight (8) evenly placed slots in the rotor.
The REALLY important factor for the rotor to work effectively is its fit within the Porting Cylinder, which needs to be quite loose. The bore clearance needs to be at about 5 thousands of an inch (sorry for mixed units!), and it’s axial clearance when the Porting Cylinder is clamped within the Cap is again about 5-thou. Clearances any tighter than these numbers will mean that the siren will not start, as the starting torque is quite limited, and any contamination or particles in the steam will jam it in place.
Porting Cylinder
The Porting Cylinder is, without doubt, the most complex component. It houses the rotor, with a retaining lip at the lower end, and the rotor is located by the cap at the top. The Porting Cylinder is held in place by the Distribution Plate below it, as the Cap is screwed down tight on top.
The porting cylinder has two sorts of slots/holes machined into it. The long slots (4 off) probably provide most of the sound. They are machined tangentially into the Porting Cylinder, this is so that the steam passing through these ports causes the rotor to spin and produce the siren sound, as the steam is released and cut off.
As it is possible that the Rotor stops with the above 4 slots covered, and thus no steam would flow to start the Rotor spinning. For this reason 10 “starting ports” (holes) are also machined into the Porting Cylinder walls. These are also tangential, and “ensure” that some steam flows to start the Rotor.
A good view of the tangential starting ports/holes and slots in the Porting Cylinder – note three starting ports between these two slots.
A spreadsheet showing the angular positions of the 4 slots and 10 ports in the Porting Cylinder
The Porting Cylinder is machined by holding it in a rotary table on the milling machine, while the ports and slots are machined by plunging a slot drill into the walls of the Porting Cylinder.
The location of the ports (10 off) and slots (4 off) are dimensioned on the drawings, but the angular positions are shown in the adjacent table. My maths was not good enough to produce a symmetric and even spacing, but actually I think the asymmetric spacing probably adds to the sound quality!
Tangential Positioning
The tangential billing is achieved by off-setting the centre-line of the Porting Cylinder from the centre-line of the drill, by 19.8mm. These dimensions can be seen on the drawings.
Final Observations
It is a very satisfying object to make and to use – even drawing admiring comments from other berth-owners at Befur’s marina. It is VERY loud, so some restraint is needed to avoid becoming a nuisance. Feeding it via a ball valve allows the siren to be played very effectively, from low growl to deafening howl. – who knows, maybe if we complete the Trumpet it will be louder yet!
It does generate a deal of condensate, so aim the outlet away from the the passengers, to avoid giving them an impromptu hot shower.
I’ll probably continue trying to make the perfect steam whistle, but for now we are happy!
Picture Gallery of Components
Porting Cylinder and Rotor installed in the Cap.
Three starting ports and two “sound” slots in the Porting Cylinder. You can see the edge of one of the rotor slots at the bottom of the sound slot at the right.
Siren porting cylinder and rotor assembled in the cap.
Cap and Elbow
Cap showing threads
A set of partially complete components
A good view of the tangential starting ports/holes and slots in the Porting Cylinder – note three starting ports between these two slots.
Well we had quite a good year, but a rather wet summer and too much playing with old motorcycles meant that Befur saw a lot less sailing and steaming than planned… but she performed pretty well.
The pictures below provides a summary of some of the activities we undertook.
Projects
During the year we undertook a couple of projects, firstly to make a better whistle, and when that failed making a siren for Befur (and that’s the subject of another post). and some maintaining things, (remaking the auxiliaries manifold, hunting for vacuum leaks) still that search for vacuum and silence!
Winter Work
In overview we are planning to do the following things in the next weeks:
Cleaning the inside of the boiler, removing oil t0 improve efficiency (reduce fuel consumption)
Cleaning the inside of the condenser, for same reasons and improve vacuum.
Remachining the LP crosshead and glands as it is now clear that this is the principal source of the hateful knocking the engine makes.
Replacing the pump drive worm box, as this is at the point of failure, and adding “assistance springs” to reduce the torque requirements on this box, to extend its probable life! (probably another post here too).
Replumbing the condenser to be “contraflow” as this should improve it’s efficiency too.
Attempting to design and fit a clutch to the prop drive to allow it to freewheel when sailing.
Attention to paint and varnish
Possibly fitting a reinforcing inner fore-deck and removing the anchor chocks and resealing to improve weatherproofing.
Wow, that looks like a lot of work when you write it all down!!!
A pictorial review of 2023
Hover over image to see caption, or click image to access full size versions.
Famous at last – front cover of the 2023 Windermere SBA Layup Supper.
Hauled out and in the Lane’s barn ready for some winter work
Making a nicer whistle – version #4 (at least)
A set of partially complete components
Swans bring new Signets to introduce them to Befur (the bread & cake boat)
They are getting the hang of it!
Steaming with friends – Russel & Maurine on Obsidian
The Maltbies – a day out with Grayling
Steaming with Shamrock – a nice steam down the lake
A new boat in the fleet: John Knapton with Anachronism!
The Skipper in the sunshine!
Back in Heggerscale – ready to be washed and ready for Winter work
Back at Heggerscale, waiting for a wash and some maintenance
Finding a new Generation of Steamboaters – “Keeping your feet dry” at Fell Foot
The KYFD class of ’23
Wasting boating time on old british bikes and sidecars!
As a last post on the subject of correcting the valve timing on the Leak Compound in Befur (prior to “sea trials” later in the year), here we will look at the results from the static (blowing) valve timing tests, and compare to the results prior to rebuild. But first a video of it running on air with the new timing…
I just updated this post to improve the pictures and ordering to allow simpler comparisons between old and new timing data.
Well, Befur is back in the fells for some winter work.
The pull-out and trip home was uneventful, thanks to Simon and Dean’s help, and the garage finally finding and fixing the leak in the Land Rover’s turbo pipes! Much less smoke and much more go!
Work to do
We have a tentative list of work we want to do, and the game plan is to try to get back into the water before Heggerscale freezes (the lake is a milder climate to over winter in)! However, as I write this post, and document the work, it seems questionable if we will finish the work in 2022!!!
The work falls into several groups, some just inspection/maintenance and some fixing/improving: Continue reading →
A memorable week: variable weather, lots of friends,
some mechanical mayhem
The first week of August is “Windermere Week” for the SBA, where a number of members gather, with their boats, and a number of marine and social events occur. This year it marked the 50th anniversary of the SBA, so more jollity was ordered and delivered. Continue reading →
While these are not drawing errors, they have emerged over the first 3 seasons with the engine, and should be considered by builders.
HP Valve Chest to Cylinder Joint
In the BOOK the designer suggests using Araldite? as a jointing/sealing material… its not a solution, particularly for this joint.
The joint between the HP Valve Chest and the HP cylinder is problematic, as the sealing faces are very thin, and the two components are only secured by 4 bolts, which are hard to tighten and not well positioned to ensure a steam tight joint.
My first attempt was using “SteamSeal” jointing compound – this failed quite quickly.
The second attempt was using “Heldite” jointing compound – this failed within a few hours.
My last attempt was using “Oakenstrong” gasket paper, I had resisted this, not wanting to affect the overall block dimensions. However, rebuilding with gasket paper and jointing compound (Heldite) does seem to have cured this problem.
Lubrication of “small ends”
I spent a long time chasing a knock that appeared to come from the LP small end. Rebushing the piston rod and a new pin did not cure this, and it was clear that the pin was suffering.
This was finally cured by increasing the size of the Lubtech pump units feeding these bearings and slide ways. A “black” one (0.1cc/stroke) silenced the knock instantly.
I am sure that a better builder than me might make the sideway fits better, but the lubrication points at the bottom of the piston rods have to lubricate the “small end” and the slide-ways, and so need a heavy oil flow to ensure that both bearings are supplied on each cylinder, as I think the oil preferentially flows to the slide-ways, starving the bush at the lower end of the piston rod.
As April begins the weather returns to snow and cold, so it seems a good time to provide a progress report.
We are working towards getting Befur into the water for 2019 – I was hoping for April 1st, but (as always) I am behind plan. However, it really is too cold to be on the water, so we will remained chilled about our position.
So, here is a list of the main activity of the last few weeks:
This post continues/concludes the story of manufacturing a new crank for Befur from the last post.
Here we can see the re-assembled engine with new crank. We are still to install all the ancillaries (reversing gear, lubrication, condenser and feed/air pump & alternator drive.)
It took 6-man days from receiving the crank back from the grinders to reach this stage.
Once we have tested it on air, we will reinstall it on the boat and undertake this year’s boiler test and check all is as it should be.
Those of you who have been following Befur’s progress will know that our first year in the water was marred by the failure of the crankshaft in the Leak Compound engine I built.
This post deals with the manufacture of a replacement, and the results of my research/experience into the approaches to building cranks for “small” (<20HP) marine steam plants.
SY Befur 