Saturday, 17 June 2017

Propulsion Machinery - Final mechanical post for now, I promise

This will be the last of the posts I have done about Enfys' machinery - until something else goes rusty or falls off! 


I had to get the engine up to replace a very rusty sump-oil-drain tube and whilst the motor was up out of the bilge I tacked a few other jobs. Having no facilities or need to remove the engine completely from the boat I devised a pair of 'A' frames that stood on the side decks with a strongback between them, over the engine. From this I slung a basic chain hoist with a 500kg capacity (the Beta 20 has a stated weight of 105kg). After disconnecting the engine's pipes, cables and wires and spending a whole afternoon unbolting the rusty clamp coupling and getting the mounting screws out the engine was ready to lift.
The engine was lifted up and turned through 90degrees and placed on blocks that spanned the cockpit floor frames.
Lifting engine


Engine now reasonably accessible
The sump oil was drained and the after a bit of a struggle the rusty elbow and pipe was persuaded to part company with the sump.  New parts were obtained from Beta marine and elsewhere to renew these and also the flexible engine mounts.
Now, I have to say that in my opinion, none of these parts is really suitable for use in a damp salty marine environment; the drain hose is a standard industrial hydraulic hose and the crimped ferrule was just crumbling. Three of the four flexible mounts were totally 'minty'. I found that they were of Italian manufacture and are most commonly fitted to air compressors; made of pressed mild steel and cad plated. To try and prolong the life of the replacements I painted them thoroughly with zinc-rich primer and a few coats of machine enamel.
Rotten sump oil drain connection

Beta engine mounts disintegrating in the marine environment
The whole lot of rusty engine parts were cleaned, treated and painted in some 'Carmine Red' enamel to match the supplier's original spec before being reassembled.

New engine mounted loosely fitted
Whilst the engine was accessible I fitted the Beta-supplied (and very expensive) 'upgrade' of the poly-vee auxiliary belt and pulleys to rid her of the curse of the 'black-dust' and tri-annual re-tensioning of the original 'V' belt. I stripped the alternator again to clean the belt dust from its innards.
Front of motor caked in belt dust - a well-know problem with these early Beta engines

New parts obtained and ready for fitting

Poly-vee kit fitted. A chunk had to be ground off the raw-water pump to let the belt pass.
Whilst the engine was out the bilges were cleaned and painted and the prop shaft was withdrawn to enable replacement of the outboard 'cutless' bearing. The propeller shaft was found to be worn and we were concerned at how badly the propeller had been corroding.
Bilges cleaned...
....and painted.
 
Badly pitted prop, and worn shaft
The 'cutless' bearing was chopped up and pulled out and the housing polished inside with emery on my electric drill. A new sleeve was pressed in as shown...
Method of getting the old 'cutless' out
Winding in a new bearing sleeve

New 'cutless' in place
A new shaft and propeller had been ordered and reeling from the cost I was determined to find out what was wrong with the existing galvanic (cathodic) protection (or lack of it!).
Enfys has a pair of zinc anodes bolted back-to-back through her sternpost that appeared to be connected to the outboard bearing housing. Inboard there was a wire connected between the stuffing box and engine's gearbox.
I made some continuity checks and found that although there was a circuit between the anodes and outer bearing there was no circuit through the stern-tube - it was open circuit, which was quite a surprise! This fact, coupled with the fact that the cable between stuffer and engine was also O/C and that there is an insulating flexible member in the propeller shaft coupling meant that the prop had probably been fizzing away merrily.
What I did to mitigate this was to fit a 'new' anode to the hull with through-hull studs (more holes in the planking.. arrgggh!) which was connected to the stuffing box and engine by new cables. At the prop shaft coupling a stiff copper wire bridges the flexible member. Now, checking continuity the propeller and shaft are all bonded to the anode.
Something odd - sterntube is corroding inside shaft log/sternpost - no continuity to the outboard end, too.
New zinc 'pear' anode fitted to hull

Connecting wires fitted to studs - backing pads will be needed at a later date.

Cable clamped to stuffer with a jubilee clip

Bonding wire connected to gearbox - flexi coupling was also bridged.
Engine back in place, lined-up and coupled
Engine back in place
 The lifting frame was rebuilt and the engine lowered back into place and carefully re-aligned with the shaft coupling.
Another job that I did whilst the shaft was out was to renew the stuffing box packing. A horrible fiddly job that required kneeling in the bilges - but I'm glad I've done it as the annoying drip from the gland has now gone!

The 'plumbing' and wiring was all re-connected, fuel tank refitted and filled, fuel pumped and system bled, batteries switched on, water hose laid on and she started and runs!




Thursday, 23 March 2017

Engine Work 2

Here is the second of a few non-Finesse specific posts but as a practical boat owner who does all their own repairs and maintenance I thought I would share on the blog..


On re-commissioning Enfys last season we discovered that the engine's alternator was not charging. A quick check of engine wiring loom and controls revealed that the alternator was receiving its excitation voltage but the output was dead.
N-D Alternator - Loose wire protruding from rear cover is a direct connection to one phase
of the AC windings and provides a pulse-train for the tachometer


I removed the alternator and took it home.  Usefully (not) the engine mariniser had sprayed paint all over the data plate making it illegible so it took a bit of detective work to find out that the alternator is a 'Nippon-Denso' with an output of 40A.  It was the internal voltage regulator that had failed - there was no visible damage or corrosion - it just decided to stop working after the winter lay-up. I must say how poorly and cheaply-made this machine is; not really suitable for the marine environment, in my opinion. Pricing up a replacement showed that it was not cheap to buy though... despite being the same as used on plant-based Kubota engines.
The regulator is the module on the left with a heatsink on its back.


Regulator assembly


After a couple of attempts a correct replacement regulator was sourced from an auto-electrical parts supplier and the machine was re-assembled and tested on the bench by spinning it with my electric drill. Whilst in the vice I blew copious amounts of black dust, from the 'V' belt, out of the machine's internals.
Connected up for test. My 'test' battery is a little tired.

Thursday, 9 March 2017

Engine Work 1

Not unique to a Finesse but Enfys' engine is a 20hp Beta based on a 3-Cyl Kubota industrial engine.  Sometime prior to our purchase of the yacht there had been a water leak at the raw water outlet at the back of the engine probably caused by a poorly-fitted hose. This would have been typical of the shoddy standard of this particular engine installation that was noticeable elsewhere too.
The exhaust outlet was heavily corroded and I noticed a crack had appeared in it - time for replacement.
Finally got the old elbow off leaving three broken bolts in situ.





The fixing bolts were M8 mild steel and might as well have been made of chocolate as three of them sheared off as soon as I put the spanner onto them. After a bit of sawing and hacking I got the elbow off.


Remains of the elbow after my hacksaw had done its stuff




The reason why the corrosion was so bad soon became apparent; the heat exchanger and elbow are made of aluminium alloy and were jointed by a copper-faced gasket.. doh!


Copper faced gasket had been used on original assembly


I had to remove the whole heat exchanger from the engine and put it on the bench to tackle the removal of the broken bolts.  It was assumed that these would need to be drilled out and the trashed holes would need to be 'Helicoiled', however, to my surprise I got all four out and cleaned up the blind holes with a tap. A new elbow and joint gasket were sourced from Beta Marine - the new gasket was fibre. Instead of using new bolts I 'Locktighted' M8 threaded studs into the holes in the casting and bolted it up with nuts and washers - hopefully making it easier to remove next time.


Studs fitted once mating face had been cleaned up

New elbow fitted to heat exchanger

Next post will cover another corroded pipe and fittings on this engine...

Monday, 14 November 2016

Hatch slider repair

Whilst working on Enfys' deck and grasping hold of one of the hatch runners I felt my fingers dig into the forward end of the port side one - a soft-spot had been developing adjacent to where a fastening holds it through the cabin top.  I didn't want to leave this freshwater decay too long in case rot spreads into the ply cabin top - much more difficult to repair - in my opinion.
Tell-tale blackened timber
The slider top was removed and the runner cut down and back to sound timber. A single screw fastening was removed - driven through from below. Once cleaned up I found that the runners had been fastened down on top of the deck sheathing so the plywood deck had only been getting wet in the area immediately around the single screw fastening and seems sound. The original glue was very dark - Resourcinol?
Cutting back to good timber
A simple 'scarf' was cut and a new piece of Iroko was worked to suit. This was epoxy glued and screwed into place.
New section glued and screwed
Job done. A bit of sandpaper and varnish was then all that was required.
There is a similar patch forming on the forward end other rail and this will have to go on the next winter 'worklist'.

Wednesday, 18 May 2016

Finesse 24 Standing Rigging replacement

The existing standing rigging on Enfys was more than 10-years old, possibly even older.  Although it looked in good condition the surveyor had 'recommended' its replacement.
At the end of the bad winter weather we chose a time to get the lay-up cover off and with the boat on hard-standing I arranged a small team of helpers and we lowered her mast.  A ladder lashed to the pushpit was the landing place and it came down without incident.
The six shrouds, backstay and forestay were removed together with their bottlescrews - all marked to show their original in-service lengths.  There was a bit of head-scratching as to how the headsail furler came apart but eventually I worked it out and dismantled the inner liner allowing the wire to drop out. The complete set was sent away to the riggers and a couple of weeks later a nice new set arrived by courier.
Forestay inside lower end of furling tube
Whilst I was waiting for the new rigging to arrive I took the furler top swivel and furling drum apart to service their bearings since they both felt stiff and a bit 'gritty'.  I like their design; being able to completely strip them down to clean and re-grease the ball bearings before re-assembling them.
Furler top-swivel in bits

Furling drum bearing assembly removed for overhaul
Another job that was done with the mast down was to remove the wind speed and direction unit - the anemometer had lost its cups shortly after we bought Enfys and I decided not to spend £120 on a new one! I pulled a new cable in for the masthead light and as I did so an electrical cable tie was wrapped around every yard or so and left full length in an attempt to wedge the loose wires in place inside the mast to stop the annoying cable slap we had been enduring whilst afloat.
Nice shiny new rigging. The bottlescrews are chrome-plated bronze

Cap shrouds re-fitted to cross-trees


Re-fitting forestay. The liner is an open figure '8' of plastic that had to be slid in 1m sections into the tube
With all the rigging re-mounted and a new staysail halyard and block shackled to the fore side of the mast a party was assembled and the mast was re-stepped. To my relief all the lengths were spot on - thanks to the care taken by the riggers.  They had informed me that although both cap shrouds were identical in length, all four of the lowers were different! They re-created the differences and one can only assume it is to do with variations in the heights of the boat's chain plates.


Preparing to raise her mast..

She's up.



Thursday, 21 April 2016

Repainting the boat's bottom

Once stripped of old antifouling (which I think is the first time since she was built since the thickness and weight of paint was staggering), three coats of underwater primer (International Primocon) were applied to the timber, the first coat thinned by about 10%.  She was lightly sanded between coats and one or two fastening heads were filled and faired.  To my great relief, despite the boat's age, the bottom planking is in great condition, no damage, splits or shakes and all the fastenings look good and tight. Painting the bottom of a clinker hull lying on one's back is quite fiddly, making sure that the plank edges all get painted. I see the GRP yachts being roller-painted in a few minutes but I used a 2" brush and took my time to get a nice smooth finish.
Once the timber was primed I chipped and de-rusted the ballast keel (iron) and bilge keels (steel plate) to the best of my ability.  I would dearly like to have the bilge keels properly grit-blasted and then galvanised - as they possibly were when new - or have new ones fabricated since these are now getting quite deeply pitted in places. However, for now the iron and steel was given two coats of zinc-rich primer and then a coat of Primocon. There is a zinc button anode on each side of each keel, through-bolted. I fitted new ones this season since the previous ones were pretty much exhausted after five years part-time immersion.
I applied two coats of 'Cruiser' antifouling.  It states on the tin that one coat should last all season but examining the small print reveals that when antifouling from scratch i.e. not recoating, then two coats must be applied.  One 2.5l can was enough to give the hull two-coats and the rudder also.
The boot-top was then masked off and two coats of hard antifoul applied (International Trilux)

Primer - three coats applied over a few weeks as other works were being carried out
First coat of antifouling paint
Antifouling completed, boot-top applied and anodes fitted to bilge keels.
The bottom of the boat will never look better.






Tuesday, 19 April 2016

Bottom paint preparation

After numerous sessions of stripping off the old antifoul back to bare wood, including taking the boot-top off. I found that the topsides paint overlapped under the boot-top and that the builder had actually scribed a waterline in - although completely buried in the paint.
I left the areas nearest the waterline till last especially near the bows that got the afternoon sun since I was concerned that she would dry too much and open up.
Stripping the old bottom paint - she was carrying a huge weight of paint
On some of my stripping sessions the weather was so damp that there were was salty water dripping from the planking. The bottom was sanded and looked so good that I considered giving her bottom a varnish finish! - Only joking!



Bottom sanded ready for primer.


The weather was dry in late February, early March so I started to get some primer on, thinning the first coat with about 10%. International Primocon was used.



Primer going on the areas that were already bare.