Aquagen towed impellor - replacement

[Ric]

Some pikey nicked the Aquagen ATMB towed impellor last night - sailing along nicely then a bang and it was gone.

Replacements are absurdly priced - over €300 for a 90cm piece of 316 steel.

So I want to make my own. I can buy a new set of 113mm blades for about €40 which is reasonable,

But what I can’t remember is whether the mounting for the blades is pitched? Or do they just mount at zero pitch and all the pitch is in the blades themselves?

I should have taken measurements and photos before it got nicked. If anybody has one they could measure/photo/weigh as a template would be most helpful.

 

[Graham376]

If it's the same as the LVM Aquagen, the blades are pitched - Microsoft Word - Aqua4gen instructions.doc (absak.com)

 

[TSailors]

You can probably eyeball it from the few photos at the site..
Hydro Generator AquaGen 12V and 24V

 

[Ric]

Thanks - yes I can see from the pics that the blades are indeed pitched, which will make it a bit hit and miss to make another one. Maybe not worth the bother.

I guess I’ll have to buy an OEM version but make sure I take all the measurements and angles so I can make another if necessary.

 

[Neeves]

There is a plastic fitting at the end of our shaft and from memory the pitch is about 30 degrees. I made replacement blades from stainless plate for ours, I wanted smaller than the smaller of the 2 blades supplied. If we make 10 knots the shaft leaps out of the water/waves. I simply rounded the leading edge of the new blades and thinned the metal off - works fine. From memory the blades are secured with 2 x 3 or 4mm bolts with a recessed Allan key head

I guess you could machine the plastic fitting to make a new hub/boss (?) but equally you could simply weld a couple of blades on to a hefty stainless rod - its not very sophisticated.

Jonathan

 

[Rappey]

The aerogen blades look like cut down turbine blades.

 

[Ric]

Thanks - if Rappey could measure the pitch angle then I will make my own version. The OEM blades are only €40 so I would prefer to use them rather than just weld on some flat steel blades.
I agree pitch looks about 30 degree - but would like an exact measurement if I can get one.

 

[Rappey]

Hope you can extract something sensible from the pics.
Looks to be 14 to 15 degrees ,ignoring the curved over part