AquaDrive Thrust Bearing Running Very Hot

[sailingmonica]

Our sailboat is equipped with an Aquadrive system (CV 15 with a B10 thrust bearing). The thrust bearing area gets hot while under power (4 knots) and gets so hot it starts to smell if we increase the speed to 6-7 knots. Then, if we reduce the speed the smell is gone, so I assume the temperature goes down a bit. Still, it is so hot you cannot touch it.

Then, last year we actually ordered a new bearing and replaced it. Still, it is as hot as ever.

If it matters, I even changed the transmission from a 2:1 to a 3:1 to reduce the number of RPM to the shaft so as to keep the Aquadrive temperature down. It did not change anything.

We asked around and were told these systems do get hot, and it's OK.

I was wondering, however, if anyone on this forum has experienced this.

Here is the unit.

ModuLine B10 Series - Marine - GKN Service International GmbH

[DeepFrz]

Some time ago, like 3 or 4 years ago, I found some specs. on the Aquadrive that rated them for different hp. They were rated for pleasure up to commercial and the units that were rated for X hp. were only rated for limited time use under those power ratings. Does that explanation make sense? In other words, the power rating was for intermittent use and you needed a larger unit if you were going to run continuously at that power.

Anyway, I would suggest you take some temp. readings and get in touch with either Aquadrive or the distributor and find out from them if the temps. are within spec. for continuous operation.

[goboatingnow]

surely an email to GKN's aquadrive would sort this, its seems excessive

dave

[boden36]

We have an earlier version of this system on a heavy 36 ft yacht. Motor power is 36 hp Yanmar JH3 with 2.8 reduction.
Over many years we have not been aware of any heating issue. In fact the system seems pretty well bullet proof.
If you haven't already, ou might want to check the alignment of the thrust bearing mounts. If one side is taking up more of the thrust than the other, that uneven loading could cause a problem. Maybe the rubbers are uneven in size or the distance between the two bits that squeeze on the rubber is unequal.
Regards, Richard.

[DeepFrz]

This PDF has a graph showing that the slower the shaft speed the larger the unit for a given hp. Seems counter intuitive but it probably is because of assumed propeller diameter/pitch.

http://www.lancingmarine.com/Aquadrive.pdf

This one clearly lays out the max. continuous power ratings for power boat and for sail boat.

http://www.poseidon-pde.nl/docs/aquaDrive.pdf