Category Archives: Hands-On Tips

EXHAUST ELBOW MAINTENANCE

If you have a Yanmar engine and have been reading the manual,  I´m sure you know that the elbow (Riser) on the exhaust of the engine should be cleaned every 250 hours or once/year.

I got this picture from a friend with a Hallberg-Rassy 34.  As you can see the elbow is plugged to   98 %. Only a small hole left.

Plugged elbow on a Volvo Penta 2030

Plugged elbow on a Volvo Penta 2030

The exhaust elbow is living a tough life, and is one of those parts that will have to be replaced on most engines.  The exhaust elbow is the mixing point of very hot exhaust fumes and salt water.  A very hot and corrosive environment with carbon deposits.  (Another reason you should do the Italian tuning)

Volvo Penta does not mentioned anything about inspection in their manuals.  Nevertheless,  I recommend that you include a check of the elbow independent of the engine manufacturer.

REPLACING CUTLESS BEARING (part two)

When removing the cutless bearing, corrosion was discovered on the propeller shaft. During the winter I contacted VETUS in Athens.  They provides excellent service and delivered a new shaft in Duplex steel to Leros.

In March I spent a week in Leros installing the new shaft, and doing some other maintenance work.

The new cutless bearing was glued in place with epoxy.  In addition 2 set screws secures the bearing in the GRP tube.

New bearing sticking out 20 mm from the tube.

New bearing sticking out 20 mm from the tube.

Then it was just to fair the area around the cutlass bearing with a filler.

Cutlass bearing installed

Cutless bearing installed

Back in the engine room it was obvious that the shaft was not centred in the stern tube.  I realized I had not checked this when removing the old shaft.  But after looking on the wear in the shaft seal it was obvious that the shaft had been sitting low for a long period.

Shaft touching the tube

Shaft touching the tube

The fact that the shaft is not centered in the shaft tube does not necessarily  mean that the engine has been misaligned.  It is possible to align the engine perfectly even when the shaft is not centered.

A proper alignment includes two steps.

1. Center the shaft in the shaft tube. This is done to make sure that the shaft does not touch the tube when motoring. When centered there is about 5 mm clearance on each side of the shaft.  Normally you use 4 wedges in order to center the shaft.  Another easier way is if you manufacture a tool that fits in the propeller tube with a hole for the shaft.

2. Next step is to align the engine to the shaft when it is centered in the tube.   Make sure that shaft is centered in the tube with the help of 4 wedges or the tool. Then it is time to adjust the height of the engine.  You have to adjust the engine until it is aligned vertically and horizontally. Then you have to make sure that the shaft coupling is parallel  with the gearbox.

Realigning the engine is something that requires skill and proper tools.  I had the intention to do this myself, but soon realized I did not have the proper tools.  I asked Nikkos on Artemis Boat Yard if he knew anyone that could help.  A local mechanic, Chris, came down and discovered that shaft was off-center and the engine misaligned.

Chris declaring , job is done!

Chris declaring , job is done!

Even with the misalignment the engine has run smooth. That just show how efficient a Centaflex  take up misalignment.  Or perhaps is it a proof that alignment is not that sensitive?  I did find this interesting article about free floating semi self-aligning system.

Centaflex CF-M 160

Centaflex CF-M 160

When loosening the bolts that holds the flexible mounts, all came loose but one.  The one that was stuck, was the one under the water pump.  Water from the pump had dripped down in the thread and caused corrosion.  Heavy tools were needed to loosen those bolts.

After 2 hours Chris said, “now it is perfect”.

This all started as a “simple” job. Without complications it would have been a 3 hours job.  But as always surprises showed up:

1. Shaft needed to be changed due to crevice corrosion.

2. Shaft not centre which meant alignment required.

3. One bolt holding the flexible mount was frozen in the thread.

Dealing with complications are much easier if you have time and are in a place with good infrastructure. This is why I prefer to schedule this type of work when the boat goes in to storage.

If you missed part one “How to replace cutless bearing. Click here.

 

 

 

 

AIS SART

When the AIS SART devices became available 4-5 years ago, we bought two RescueAIS. They are clipped on to our life vest.  The unit we have can be activated in two different ways.

1. Automatic activation when you fall in the water.  I think this is very important as the person will most likely be in shock.  Finding a small button in the water would not be easy.

2. Manual activation.

The idea with a AIS SART  is that the crew on the boat should be able to find and rescue the person in the water.

The AIS SART  is a portable device that includes a AIS transmitter and a GPS.

EasyAIS

When activated it sends identity and position on the frequency for AIS.  If you have a AIS on-board  a target will show up on your plotter.

I have always wondered how this target would look?  

This summer we got the answer.  The AIS SART  was activated by mistake as it was jammed into the hanging locker.

I was looking at another AIS target that was lying more or less on our boat.  We sailed and this target sailed as fast and in the same direction as Bella Luna. No other boats were in sight!

After 1-2 hours the coin fell down, and I opened the hanging locker.  Sure enough, the little LED on the AIS SART  was flashing.

So now I know how the target looks on a Furuno Navnet 3D plotter. 

It looks no different from other targets (boats) on the screen.  The only difference is that the MMSI number starts on 9.  Off course it would be better if the target would be displayed as in the example below.   But as long as you understand how it will look, I do not consider it as a big problem.  How the target looks on your plotter, depends on the software in your plotter.  According to Furuno, the new software version 2.11, will display a proper SART icon.  

How it looks and sounds on a Raymarine Plotter you can see below.

Other options for finding MOB and boats are PLB and or EPIRB.

The main difference between a AIS SART  and PLB/EPIRBS is following:

AIS SART  transmit position and ID to your own boat which means you can find and rescue the crew member yourself.  Other boats with AIS receivers that are also close to the MOB will also be able to help in the search & rescue.

EPIRB and PLB send ID and position over satellite to a rescue coordinator.  That might be the best alternative when you are in the life raft, but not swimming in the water as.