Damaged prop

[Fenders]

Boat lifted today for annual antifoul, anode change, etc.
After pressure wash of hull, keel and rudder I noticed that the prop was badly corroded on the end tips.
Very shocked at what I saw and quite clearly needs to be replaced. After removing the prop I had a good look at it for any markings but none were apparent.
So I am after recommendations for a suitable replacement without going silly with the budget. I have no idea of the size/pitch.
The boat is a 2004 B32 with a MD 2020 and saildrive. I think the saildrive is a 120s but having read extensively on the inter web I believe that there may be other models.
All the boats manuals, etc are on the boat and so I cannot refer to them to confirm the saildrive unit until I go to the boat next week.

My current prop is a 2 bladed fixed one, but I notice that there are also 3 bladed fixed ones as well. It has a rope cutter in between the prop and the anode.
Would I be better off with a 3 bladed one bearing in mind the price difference?

I am guessing the condition of the prop may be caused by galvanic corrosion so should I consider installing a galvanic isolator?

[Symphony]

Corrosion of the standard aluminium prop is not unusual and there is little you can do about it except check that the isolating washer is in place behind the cone. This isolates the prop from the shaft along with the rubber bush in the hub.

Little advantage in having a 3 blade and there is a big increase in drag. However big advantage in fitting a folding 2 blade such as a Flexofold which in every way is superior to the standard prop (but of course at a cost).

The size will be on the hub but is usually hidden under crud and paint. Would not worry over much if you cannot find it because any prop supplier (Keypart, Lake Engineering for example for fixed props of Darglow for folding) will know the correct size.

Remember to tell your supplier that you have a rope cutter so that they can machine the hub to take the drive pegs.

[Escapade]

Hi Fenders
Your engine should be the MD2020-D which was the last series manufactured under said name.
The saildrive could be either the 120S-E or the 130S-A as they were both used with your engine.
What Symphony says about corrosion is correct and apart the checks he has suggested there is not much you can do.
By design the saildrive should be electrically isolated from the engine and the ground of the boat electrical system, hence a galvanic isolator may not produce much effect.
When I purchased my boat 3 years back I have found a Kiwiprop feathering prop installed and it is made by a DuPont composite material and a Stainless steel hub.
You may read about at the following link

http://www.kiwiprops.co.nz/cms/index.php

I realise it may not be the most performing prop when compared with Autoprop or Flexofold, but in turns it is not affected by corrosion.
However Personally I am happy with the performance, about 7kn @ 2600 rpm (MD2030-35 foot boat 5.5 tons displacement flat sea- no wind).
Being a 3 blades it has a bit more thrust, while being feathering it performs very well in reverse and it has less drag than your prop when sailing.
Look at the picture, It is about 10 years old now.

Only draw back .... about 1000 pounds + VAT.

Cheers
Oliver

[Symphony]

Regarding the saildrive your boat was built around the time that the 130 was coming in (2004/5) but suspect it will be a 120. Important to know which as the reduction ratio and therefore prop is different. However very easy to tell. If it has a one piece anode it is a 120 and two piece bolt-on a 130.

[Fenders]

Escapade
You are correct in saying that my engine is a MD 2020. I believe that 2005 onwards Bavaria started installing the new D1 series.


Symphony
I believe the saildrive is a 120 series. It does have a one piece anode which I cut out a notch so as to accept the rope cutter.

The prop has the markings 17-15 stamped on it which I understand to mean that the diameter is 17” and the pitch is 15”.
Having looked at the Volvo propeller guide I cannot see a propeller with these dimensions. Of the 17” diameter propellers there is only an 11 or a 12, so no direct replacement for my 2 blade fixed propeller.

I will contact Volvo and Keypart and see what they suggest.

Thanks again for your replies

Fenders

[Fenders]

I have just found at Falmouth Yacht Brokers website that they have several different 17” propellers, a 14, 16 and a 17 but not a 15. I will call them and report my findings.

[Symphony]

Highly unlikely it is 17*15 - that is the sort of size for a 50hp+. Pretty sure is should be a 15" or perhaps 16". I have had a 2030 and a D1 30 and they both had 16".

Try www.lakesterngear.co.uk who sell the Radice props which are the same as the factory Volvo ones if you want to stick to a fixed prop. Otherwise Darglow Engineering for a Flexofold folding prop.

[Darren]

I have just removed my prop, cutter and anode from my 2001 34, it has a MD2020D and the saildrive is the 120. The aluminium two bladed prop is marked 16 x 11L and gives a good 6 knots in flat sea.
Hope that helps