Tuesday, 29 October 2013

Craftsman Marine Diesel Trial Fit

Hi everyone,
Our engine replacement is continuing slowly but steadily.  Coping with the inevitable problems and cheered by finding solutions - often with the help of other yachties here at Rebak.

The second half of last week was spent completing the refurbishment of the engine compartment.  It now has three coats of two-pack polyurethane topcoat over two coats of undercoat.  Looks good.

Ready for new engine
On Saturday Barry from Nefertiti and John from Sea Mist assisted with the lift of the engine from the cockpit sole into the cabin, and from there into place for a trial fit.  Looks better!

New engine in place for trial fit
The trial fit showed that we really do need the special low-profile PolyFlex mounts I brought with me from Perth.  In fact we thought even they would not be low enough.  On Sunday I was contemplating cutting the tops off the engine beds to lower them.

Yesterday (Monday) I received good advice from shipwrights Alan and Martin.  Both thought the low profile mounts should work if the standard nuts were replaced with half-thickness nuts and an obstruction taken care of.  If the half-height nuts don't work then the engine can rest on washers instead of the adjusting nuts, but then we'd need to use shims under each mount to align the engine.

So today I took the ferry to the main island and eventually found a metalwork shop which could take four nylock nuts and turn them down as required.  Best of all the work only cost RM20 (A$7).  A little more metalwork to do, and then we'll offer up the engine again to see if it lines up with the propellor shaft.

By the way, photos have been added to the preceding post (below).

Thursday, 24 October 2013

Craftsman Marine Diesel Aboard

Hi everyone,
Our new engine is now aboard Zen Again, and the old Yanmar has departed. Out with the old, in with the new as they say. The new engine looks as good as the marketing photos. One or two issues with the supplied documentation which may be the subject of a separate post.

New engine enroute to Rebak

Please note this is a fairly detailed description of how we removed the old engine and got the new on aboard. Intended audience is those considering or planning a similar job.

I arrived in Langkawi on Monday afternoon last week. On Tuesday I disconnected the engine from its instrument panel, from its high-current 12V power and ground cables, from its fuel supply and return, from its raw water supply, from its raw water outlet vented loop and from its exhaust muffler/water-lift box. I drained the oil and coolant, then removed the alternator, starter motor and exhaust mixing elbow.

On Wednesday I was laid low by a dehydration-induced headache from the above work! In the tropics one needs to pace one's self. Particularly when not yet aclimatised. Painful lesson learned (yet again).

On Thursday I removed the instrument panel from its recess in the cockpit and the exhaust manifold from the engine. Removing the engine subsystems lightened the engine and also greatly improved access to the engine mounts and mounting bracket bolts, which I gradually managed to loosen. Used a lot of Releasing Agent. Requires a variety of sockets and spanners, including extended sockets and offset ring spanners. Loosening bolts which haven't moved for 22 years, some of which were very rusty, was the hardest part of removing the engine.

On Friday I removed the last of the four bolts securing the shaft half-coupling to the gearbox - with a hacksaw. That was the only bolt I had to remove "unconventionally". Of the four main engine mounts I managed to remove all four 24mm nuts, although one was very rusty. I also tried to remove the smaller bolts securing the mounting brackets to the engine itself, but one of those was so rusty a ring-spanner turned the hex head of the bolt into a nice circle! Sadly that one was inaccessible to a hacksaw (but an angle grinder might have done it). Small lesson there is that a similar depth or rust does less damage to a larger nut or bolt - pretty obvious on reflection.

On Thursday and Friday I also installed four through-bolted deadeyes, one forward and one aft, high up on each side of the engine compartment. To these I attached 4:1 tackles across the compartment, one under the forward part of the engine and the other under the aft part. I proved these by using them to lift the engine a few mm, and left it hanging on the tackle.
Old engine in the slings

On Saturday morning I removed the mainsail and its boombag from the boom, and rolled up the boom tent. I rigged two heavy 2:1 tackles kindly leant by Diana from The Doctor (actually their running backstay tackles) down from the boom. One was rigged over the companionway and other aft of our mainsheet arch. Barry from Nefertiti II and Alan from Langkawi BSS assisted the actual engine removal, with Alan supplying his fibreglass dinghy into which we lowered the engine alongside. ie We did this entire preparation and removal in our pen. We have a PSS shaft seal which is coping with the work all around it very well, but needs to be watched carefully nonetheless.

The actual engine removal was very easy, proving once again the pilot's "5P's" (Prior Preparation Prevents Poor Performance). The tackle in the engine compartment allowed us to lift the engine the ~30mm to clear the top of the mounting bolts, and then to swing the engine forward. We then attached the forward boom tackle to the front engine hoist point and moved the forward engine compartment tackle under the rear of the engine, and swung the engine further forward. We could then take a strop from the rear engine hoist point to the boom tackle and then the engine could be hoisted up and out of the companionway.

From the companionway it was easy to attach the rear boom tackle, swing the engine aft, remove the forward tackle, hoist the engine higher to clear the s/s lifeline and then outboard and down into the dinghy. From there Alan took the motor away. 15 minutes later the rain started - good timing!

Vacant engine compartment - ready for cleaning up
On Sunday I got to work cleaning the engine bay. First I removed the old mounts, which proved to be simple but hot, sweaty work.  Then I used a scraper on the walls and deckhead to remove the sooty remains of the contact cement which once secured insulation panels. Lastly for the day I sanded the floors which are an "interesting" landscape of frames, stringers and engine beds.

On Monday (this week) I finished sanding the compartment floor, and sanded the lower parts of the side walls which I intend to paint. The rest of the walls and the deckhead will eventually have insulation panels so I've left them alone.

On Tuesday the motor was booked to be trucked from the airport to the Langkasuka ferry terminal and from there by cargo boat to Rebak Island Marina. The truck arrived only 30 minutes late, and the boat about 20 minutes later. Manhandling the 150kg palette holding the engine onto the boat was an adventure. No crane or gantry of any kind, so 8 of us had to lift it down the ramp, onto the boat and position it aboard. Pity only 2 of the work party understood the concept of balance and centre of gravity, but ultimately we got the palette aboard the fishing boat without incident. Once aboard the crew showed no interest in tying the package down, so I found a rope and lashed the engine down (as the photos illustrate).

The trip over to Rebak Island was uneventful. We arrived during lunch hour so had to wait 45 minutes for the forklift. In the meantime I returned to Zen Again and readied everything to lift the new engine aboard. The forklift drivers appeared on time and we lifted the engine from the fishing boat to Alan's dinghy and motored around to Zen Again. Lifting the engine aboard was straight-forward and we lowered it onto a plywood board on the cockpit sole, where it will stay for the time being.

New engine in the cockpit

On Wednesday I continued cleaning. Used copious amounts of degreaser to remove 22 years of oily, sooty grime from the floor, particularly those parts one just couldn't reach with an engine present. Finally I washed down the floor with acetone.

Today I applied a first coat of two-part polyurethane undercoat to the floor. I'll apply a second coat this afternoon, then several coats of topcoat tomorrow.

All in all the removal process took about as much long as I'd estimated - 5 days, only working 5 hours a day in the heat. The process would have been quicker if I'd had all the right tools at the start - perhaps 3 days. No doubt a mechanic would have got it out in a single day, but it was a useful learning experience.

Sunday, 6 October 2013

Craftsman Marine Diesel Ordered

Hi everyone,
We've now selected a new engine for Zen Again.  We have ordered a Craftsman CM3.27 (3 cylinder, 27HP) and will keep the existing propellor.

Craftsman Marine is a quite new supplier of marine diesels.  They marinise Mitsubishi industrial engines in the Netherlands.  I've read plenty of positive comments about them and can only hope we'll be equally pleased.  Here's why we chose the Craftsman:

  • Fits in our engine compartment (and is smaller overall than existing engine)
  • Lighter (113kg compared to 123kg new Yanmar and 138kg existing engine)
  • 430mm mount spacing which matches our mounting beds.  It turns out our existing Yanmar has custom mounting brackets which extend their standard 370mm spacing.
  • Regular service items (dip-stick, filters, impeller etc) all on starboard and forward sides
  • Nice IP67-sealed instrument panel with hour, temperature, oil pressure, voltage and RPM gauges
  • Preheater (just in case we ever go anywhere cold!)
  • Nice looking engine with hoses NOT painted!

Craftsman Marine CM3.27
We expect to fit non-standard engine mounts since our engine beds are quite high.  We selected PolyFlex mounts which allow a minimum height of 65mm vice the standard mount minimum height of 85mm.

PolyFlex Engine Mount

We also plan to install a flexible coupling to provide a little "elastic" in the drive train.  We've chosen a PolyFlex...

PolyFlex Flexible Coupling

Our existing shaft half-coupling is rusty and its bolt hole pattern doesn't match modern gearbox couplings.  Again PolyFlex offers these, and drilling out to match your shaft diameter is included in the price.  So we'll get one of these...

PolyFlex Half-Coupling

We looked into the possibility of a smaller engine with a new propellor but that proved difficult due to issues matching available gearbox ratios to new propellors, and also a possible clearance problem between the P-bracket and an AutoProp propellor.

It will be interesting to see whether the new engine can drive our 16" Varifold propellor up to the engine's full rated RPM of 3600rpm.  The existing engine can only get to 2500rpm, but we suspect that's because it is producing less than its rated 27HP.

We used Nigel Calder's excellent book "Marine Diesel Engines - Maintenance, Troubleshooting and Repair" to calculate engine and propellor parameters for Zen Again.  Section 9 "Selection and Installation" provides all the necessary information.

For a yacht with the following characteristics:
  • 6,800kg (15,000lb) displacement;
  • 8.65m (28.4ft) waterline length;
  • 3600rpm maximum engine revolutions; and
  • 2.72 gearbox ratio
the calculations showed:
  • 15HP needed for a "racer", but 30HP recommended for a "cruiser"; 
  • Recommended propellor size of 16.5" (ours is 16"); and
  • Recommended propellor pitch of 14" (ours is 12").
So, if anything the boat should be slightly "under-propped" rather than "over-propped" with a new 27HP engine.  And so the new engine should work well.  Time will tell!