Bow thruster props

[Pitou]

Just a follow-up report from awhile ago. I have the Vetus 55 bow thruster and I did order and install the new 6 bladed prop. Much quieter / the power seems fine. Glad to have done it.

[george]

Anyone have this problem?
I have a 2004 28 with a Vetus 55 thruster. I ordered the new prop and found that it doesn't fit in the tunnel! The diameter of the prop (146mm) is too large. I looked at the old 3 blade prop and noticed that it too said 146mm (about 5.75 inches). However, a close look at the blade ends showed that it had been cut down (not exactly perfectly round either) to a bit less than 5.5 inches). I bought the boat new, so this was a factory fix.
So I created a jig for my drill press and ground down the OD to something that gives proper clearance when installed. After a bit of light sanding the result looks fine (better than the original and perfectly round) and I expect it will work OK. But I'm surprised to see Albin using undersized tunnels. Why not just use the right tunnel and avoid recutting the props.
I expect my fix will be OK as the thruster has plenty of power for a 28' boat as it is, even if the modified prop is not exactly as designed.

George

ps. The prop shaft is not exatly centered in the tunnel either, but I'm not going to mess with resetting the thruster this year. I looked at other Albins of various vintages in the yard and none of them appear dead on. It means the prop has to be cut even smaller than what it would be if the centering were exact.

Pps. I noticed an earlier message about some delamination in the tunnel. I too had some gel coat chip off the inside last year. The thrust tunnel (basically a PVC tube) was shinny underneath indicating there was no prep done. A bit of coarse sanding would have helped here (is Albin listening?). It was non-critical, so I had it feathered out and bottom painted over. No further problems so far.

[Pitou]

George, sorry to here of your thruster problem. I feel lucky. The inside tunnel dimensions are supposed to be 150 mm or 5.9 inches.
The propeller is supposed to be 146 mm or 5 3/4 inches. Very strange that you should have a problem. The techhnical data from Vetus is very specific. I hope your fix works.

I replaced my original prop one prior time when the yard didn't tighten the prop nut and I spun it right off. New 3 bladed prop fit like a glove with no modifications / now stored in the land of misfit boat parts in my barn with all the other parts of projects past / you never know.

This season I replaced it with the new 6 bladed prop and again no problems / perfect fit. After more beta testing I still say much quieter, but I have noticed a bit of power reduction.

[JackK]

Hey George -

I had the exact same problem. I bought the new 6 bladed prop and went to install it just before launch. No go. I also wonder if that is why my thruster is noisier than others.

This winter I'm going to turn down the 6 bladed prop on a lathe. We'll see how that goes.

Jack

BTW - Stop by and see me sometime. I saw your boat on the hard deck at Brewer's. I'm D-6 in the North yard.

[george]

I thought I'd post a couple of pics of my drill press setup (showing the old prop). Not fancy, but effective. I used a piece of wood, two clamps, a cylindrical grinding bit and a length of 3/8 inch pipe (I think). The pipe has the same OD as the bow thruster drive shaft, so the fit is nice and snug. A little grease on the pipe is a good idea. I just keep the base of the prop core flush to the wood, and turn slowly using multiple passes to remove material. A bit of fine sanding and ready to go. I should be launched early this week, so if you want to see what the prop looks like, you should check it out quickly.

George
ps. I'm normally in the South Yard - E20





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[Richard]

I just installed the new "Super Quiet" Vetus six blade prop on my 55Kgf bow thruster (it fit fine) but am very disappointed with the results. It is just as noisy (if not a bit more noisy) than the three-bladed original prop. Any body else tried the new prop and if so what were your results in terms of noise reduction? The ads claim up to a 50% noise reduction and more thrust per Hp.

[Pitou]

After almost a full season with the new 6 bladed prop, as reported earlier in this thread, Mucho quieter! This season the heads of other boaters have not turned as they did with the rattle sound of the old 3 blade prop.
As far as power / maybe a little less, but not significant to make any difference. Overall, very happy I made the swap.
Cutting out early today to chase the bluefin tuna bite.