Another hot and busy week onboard the Good Ship Möbius here in the Finike marina as we continue to work on the seemingly endless ToDo list of jobs we need to complete to get Möbius fully ship shape to the degree that we can be confident to go to sea on her. Weather here continues to be wonderful although the daytime temps have been creeping up to the mid 30’s (mid 90’s for those who are metric challenged) but we have the AirCon working very well now and use that to cool down Christine’s office during the daytime, the SuperSalon for dinners and our Master Cabin just before we head off to bed. The “eXcessive” EPDM insulation we installed throughout the boat is really paying great dividends now as it keeps the heat out and the cooled down temps in so the loads on our AirCon chiller system are minimized.
This great weather, which is normal for us in this part of Turkey, also inspired Captain Christine to take to the air as she started to log more hours with our DJI Mavic Air 2 drone. We’ve had it for quite a while but have both been so busy with boat work that we just have not had the time to fly it and become familiar with it. Christine will put together some videos she took with it and post these a bit later for you to enjoy and I can give you this aerial view of Möbius as a teaser.
This is where we are tied up at Finike Marina and will give you a different perspective on what Möbius looks like from above. Easy to see the 14 solar panels from this viewpoint.
Flying a bit further away to give you this view looking back at Möbius to help orient you as to where we are within the marina. You can Click to enlarge this or any other photo.
This pano shot from a bit further out will give you a better sense of our surroundings and where we go for our evening swim after quitting work every day.
You may recall that back in June we drove up to a big hardware store north of us to pick up a new air compressor for the Workshop and after testing it out and thinking over the best location, I got around to permanently mounting it this week.
This is one of the newer types of compressors that has two motors each with two compressors so four compressors all together. This enables each one to be smaller and run at lower RPM’s and run eXtremely quietly! I can hear it come on when I’m in the workshop but it doesn’t interrupt a conversation and you can’t hear it at all outside of the workshop.
This air compressor is a super handy bit of kit to have and in addition to using it to power some pneumatic tools, clean tight passages out and blow up inflatable kayaks and the like, we use this to provide air to breathe using our Hookah or Snuba gear to work underneath or dive down to about 20m/65ft up to 100 feet around the boat.
It was definately a shoehorned fit with less than 1cm to clear at the top but this location keeps the compressor out of the way, easy to service and uses an otherwise not so usable wedge shaped space.
And of course we continue to have some “infant mortality” jobs on the list such as when this seam in our brand new sand filter burst and started spraying seawater all over the Workshop.
While I hunt down a newer and better version I have just bypassed this for now and run the seawater supply to our Delfin 200L/hr watermaker through just our primary and secondary sediment filters for now. These “media” or sand filters are most commonly used for swimming pools so many of you will recognize this. However they are the secret weapon for dramatically reducing the maintenance of a watermaker by filtering out almost everything down to about 5 microns prior to going to the two sediment filters. We would normally need to clean those filters every 10 hours of use and replace them every month or so whereas with the media filter in front, the sediment filters last for over a year.
What I will do for the rest of this posting is go through the belt drive system I designed and built to power the seawater pump and Electrodyne alternator mounted on the front of Mr. Gee. I’ve been reminded by several of you that I promised to do this many months ago so my thanks for your patience in waiting until now. Hope the wait will have been worth it.
To put this all in context, I had a relatively large seawater pump and two very large alternators that I needed to mount on Mr. Gee our Gardner 6XB and then drive them both from his crankshaft.
The seawater pump weighs about 7kg/15lbs and each of the Electrodyne 250A @ 24V alternators weigh 40kg/88lbs so the mounting system needs to be eXtremely strong and solid. Both the pump and the alternator require a good bit of power to drive them so the drive system needed to be equally as tough and to be up for this task of years of trouble free service.
I won’t go into much detail on this but the seawater pump pulls seawater direct from the sea chest in the Engine Room and then pumps this water through three heat exchangers/coolers, one to cool engine oil, one to cool the engine’s water/antifreeze coolant and one to cool the Nogva gearbox oil before it finally and perhaps most importantly gets sprayed into the exhaust elbow to cool down the exhaust gas and then exit out of the boat.
If this pump fails for any reason, the engine would overheat quickly and cause some extreme damage. Both of these bits of kit are therefore very critical to keeping the boat running, the seawater pump in particular so I needed to come up with a design that would be as bullet proof as possible.
There are two of these big red Electrodyne brutes which have a de-rated output of 250A @ 24V and each one weighs in at 40kg/88lbs and can take up to 20HP to drive at maximum output so their mounting and driving systems have to be equally as eXtreme.
However this essentially gives us the equivalent of a 12kW “generator” whenever Mr. Gee is running so these ensure that we never have any shortage of amps to keep our batteries fully charged and power all our electrical systems whenever we are underway.
Of course we are at anchor much more than we are underway so our 4.4kWp solar array keeps the batteries fully charged the majority of the time.
But how to mount them and drive them was the big question?
Direct PTO Mounting for Electrodyne #1
Mounting one of the #1 Electrodyne alternator was relatively easy as Gardner LXB engines have a dedicated PTO driven system for driving one alternator. I had a short jack shaft in my spare parts that I was able to machine some adaptors for that connect the end of the jack shaft to the PTO output and the input shaft of the Electrodyne.
Then I was able to machine some other adaptors for these ribs where the alternator body bolts directly to the side of the Gardner crankcase.
Using this Black metal band strap to hold it all together. KISS and eXtremely strong, what’s not to like?
As you can see this was quite the shoehorned fit but was relatively straightforward to do compared to coming up with a way of mounting the second Electrodyne.
Mounting Big Red #2
Physically mounting the second alternator was actually not too difficult thanks to the nice large flat mounting pad that the Gardner 6LXB’s have on their front Left corner. This was originally used to mount things such as air compressors on the automotive version of LXB’s used in trucks or to mount water pumps on the marine versions. I had another place in mind for the seawater pump so I used this mounting pad for the second Electrodyne instead.
Pretty straight forward, I machined two 25mm thick AL plates and drilled them to match the spacing of the four threaded holes that were already in the mounting pad.
Then I machined and drilled the riser for the through bolt on the bottom of the Electrodyne and welded this all together.
This created a super solid mounting system for this second Electrodyne. Then I fabricated a SS bar that connects to the red tab you see just in front of my knuckles here, which holds the alternator in its final position and it was now fully mounted.
But how to drive this second Electrodyne AND the sea water pump was the big question!
Mounting the Jabsco 6400 Series Sea Water Pump
As you can see the pump has a simple flat mounting pad on the bottom with four bolt holes to fasten it down and wanting to KISS (Keep It Simple & Safe) I decided to go with an equally simple flat bar of 25mm thick AL which I could quite easily mount vertically over on the Right side of Mr. Gee.
Didn’t take me long to fabricate this mounting bar, bolt the Jabsco pump to it and create some simple mounts for this bar to bolt onto the front right side of Mr. Gee.
As with the Electrodyne alternators, the mounting part of this puzzle was relatively easy, now on to the bigger challenge of driving both the water pump and the alternator.
Designing the Drive System
I spent a LOT of time sketching out ideas on my favorite medium; old cardboard boxes! I would sketch up very rough ideas of every possible drive system I could imagine and pulled lots of dimensions off of Mr. Gee, the Electrodyne and the Jabsco sea water pump as I refined the design.
As my idea took shape I started searching for the components I would need for the actual drive components such as the pulleys for the belt and what their requirements were for power, RPM, etc..
I knew this was going to be a rubber belt drive system but traditional V-belts were just not up for the job even if I used two or three of them and they tend to slip quite easily if the belt tension is not just right and very tight. They also require very close alignment or else they start to wear and through black rubber dust all over the engine room.
Ask me how I know all this?!!
For a long while I thought I was going to use a multi V serpentine belt drive setup, As per this nice lineup of different V belt types of pulleys, you can see that these multi rib belts and pulleys are able to handle much bigger loads and are more durable. These are used on millions of cars and trucks around the world to drive their alternators, water pumps, etc. so they are well proven.
Better yet, I already had two of these as they came with the Electrodyne alternators I already had on hand. You can see one inside the white rectangle on the left.
However, this still left me with having to custom build a multi V groove pulley to drive all this off of the front end of Mr. Gee’s crankshaft and one to mount on the keyed shaft of the Jabsco water pump. Not a big deal in and of itself, BUT if I was going to have to build custom pulleys, why not go for an even better belt drive system?
Good – Better – Best
Traditional V belt drives are good and serpentine multi groove V belts are better but cogged belts are THE best when it comes to driving high power shafts. My Harley Davidson motorcycles used these instead of chain drives so I was very familiar with them and how well they worked.
Many of you might know of these and refer to them as “timing belts” as they are used in millions of gas and diesel engines in cars, trucks, busses and boats around the world to very accurately drive the camshaft in those engines. In that job they are required to have zero “slip” or else the timing of the valves opening and closing won’t work and they need to be eXtremely long lasting as replacing them can be very expensive due to all the labour required to remove and replace them on most engines.
Once I got onto that line of thinking the choice was simple. Amongst other benefits these cogged belts gave me the following benefits:
- Tried and True having been used for decades in millions if not billions of exiting engines
- Readily available to buy new ones around the world if ever needed. (I of course have two spare on hand already)
- Zero slip = zero belt dust = super accurate tachometer sensing on the alternator
- fast, easy, tool-less belt changing
- automatic tensioning with readily available spring loaded tensioners used in those millions of other engines
- low axial (sideways) loads on the bearings of the alternator and water pump which in my experience is the #1 cause of failure.
- Dead quiet operation; no belt squealing or squeaking
As you can see, this decision was easy, now on to designing a way to make this all work and find the cogged belt drive pulleys I would need to buy or make.
McMaster-Carr to the Rescue!
Within seconds, I got to this page that had eXactly what I needed.
A full range of these beautifully machined cogged belt pulleys. Took me a few more hours playing around with different sizes for the three pulleys I needed to get the RPM just right for the outputs of the water pump and the alternator;
* one large 142mm pitch diameter for the main drive off the Crankshaft,
* one medium size 142mm pitch diameter to drive the Jabsco pump at its sweet spot of output when Mr. Gee is at 1400 RPM cruising speed
* and one smaller 66 Pitch diameter pulley to drive the Electrodyne at its Goldilocks RPM.
In addition to the three pulleys; I also ordered the just right sized cog belts made by Gates. Only one belt is needed but I ordered 3 so I have two for spares in the unlikely event that one belt breaks at some point.
The real Pièce de résistance though came when I happened to notice down at the very bottom of the McMaster-Carr page you see up above, these “quick disconnect bushings”.
Took me a few minutes to realize just how ingenious this design was and the short story is that the smaller diameter of the quick disconnect part in my hand has a slight taper to it which fits into the matching inner hole of the cogged pulleys.
This allows the Quick Connect to slide all the way inside the cogged belt pully and you’ll notice that these Quick Connects are slit on one side opposite the keyway.
Holding the two parts together you tighten down the three bolts which forces the tapered QC to expand and jam itself tightly onto both the keyed shaft and the outer cogged pulley.
You will be forgiven for not sharing my eXcitement but for me this mounting system to attach the cogged belt pulleys to just about any size of keyed shaft was was like a gift from the mechanical gods. I quickly added three to my order and it was on its way to me.
Putting All the Puzzle Pieces Together
I now had all the pieces for this fun puzzle but still had to design it all up so that it could be installed on Mr. Gee. So I turned to my favorite 3D modeller, Autodesk’s Fusion 360 and was able to convert all my cardboard sketches into 3D models of each of the pieces and then accurately position them.
McMaster-Carr provides 3D model files for everything they sell so I could quickly download the three pulleys and three Quick Connect fittings. Took a bit longer to create the 3D models for the Jabsco pump and the Gardner parts surrounding the crankshaft but with those on my screen I could then try out different positions within the constraints I had from Mr. Gee.
This was additionally challenged by the fact that I had also designed a custom version of the Gardner chain drive hand starter system which is the black line diagram you see overlaid here.
Things were particularly “interesting” and close fitting down around the crankshaft where I needed to fit the red chainwheel for the hand starting chain and then come up with the Blue AL adaptor for it to spin on which in turn would be just the right spacing for the cogged belt pulley mounted on the custom Olive Green adaptor to attach the cogged pulley to the crankshaft.
As you may have figured out by now I don’t throw ANYTHING away and so I had kept the original 4 V belt pulley that came with Mr. Gee, even though it had a large piece of it broken away. But this gave me the center piece that was already machined to just right fit on the keyed end of Mr. Gee’s crankshaft so I cut it out with a plasma gun and used it ….
….. to quickly machine it into this part which is the Olive Green part in the 3D model above.
After making a few more parts, I could now dry assemble everything to see how well my 3D modeling transformed into the real world on the front of Mr. Gee.
Now to test how the belt fit and if all the pulley’s aligned with each other in all three planes so the belt would run true and free with no binding or chafing.
Worked out great!
BUT, there was still one critical part missing.
To mount this onto the front of Mr. Gee in just the right fore/aft position so that the black idler pulley rides exactly in the center of the rubber cogged belt, I needed to space it out about 38mm so I quickly used by drill press/milling machine to build this solid AL spacer.
Next I made up a template for the 10mm thick AL plate that this would mount onto.
Bolted that to the Gardner cast AL support bracket supporting the cast AL cooling water holding tank, held the spring loaded tension wheel out of the way while I slid the cogged belt into lace and released the tensioner.
Et Voila! It all came together and works like a charm.
Final piece of this multipart puzzle was to add in the chain drive hand crank system to make sure all the many players in this very busy front end all played nice together.
You can see just how tight some of these clearances were in all this but it worked out just as I had modelled it, all the belt pulleys and chain wheels aligned with each other so they were all happy and it has been running like a charm for the past few months now.
Whew! Sure glad I was finally able to put this all together for you and for those who were brave enough and preserved to get to the end of this long and winding explanation. Congrats to all of you who did and for the smart ones who just skipped to the end.
I’ll leave you with one parting shot from Christine’s recent photo shot with the drone. It is a bit distorted with such a wide angle but this is looking across the entrance to the marina where Möbius is a bit left of center along that stone breakwater.
Thanks for joining me here again and don’t forget to add your comments and questions in the “Join the Discussion” box below.