DPH props; are newer ones more corrosion resistant ?

[GrahamHR]

OK, I know there were issues with earlier Nibral ones. The props themselves not protected by the sterndrive anodes at all. Connecting the props to the hubs, hence the anodes with a bonding wire or fitting anodes to the props appears to have met with derision.

After 6 months of sitting in salt water with virtually no use, my 2009 ones show corrosion pitting, mostly on the hubs. They go into the water next week. I'll smear them with waterproof grease in a vain attempt, probably futile attempt to slow down the corrosion !

Are later replacement props any better?

Does anyone know if the FH stainless props with the helical splines fit the DPH ?

 

[RogerRat]

Hi,
Don't think they've changed them at all and I'm pretty sure no stainless option available yet. Despite many people asking.:ambivalence:

The pitting will go to holes before long and they will become dangerous as the break down develops. (dangerous as in can break up) Unfortunately, you will need to replace them sooner or later.

Sorry to hear, not good news I'm afraid.

RR

 

[aquatom]

We service many of these drives each year in Mallorca and very rarely see any corroded props.

 

[GrahamHR]

We service many of these drives each year in Mallorca and very rarely see any corroded props.

At the prop repair company where I recently got mine cleaned up/ polished, they had a pallet loaded up with them, too badly corroded to repair and be safe to use ! Corrosion of these props, in North Wales waters is very common according to them. Strange really, I'd have expected the lower water temperatures and salinity compared to the Med would have made corrosion occur at a lower rate here .

My boat will have an electronic active corrosion protection system fitted for this year. Hopefully that will slow the corrosion down.

 

[julians]

We've had two sets of these props in the sea in Mallorca for the past 8 years (in the water 365 days per year) and they've been fine, no corrosion to speak of.

 

[aquatom]

Another good reason to head for the med!

 

[Johntheoil]

Possibly all those 'lovely' Mediteranean barnacles stop the corrosion............

 

[GrahamHR]

We've had two sets of these props in the sea in Mallorca for the past 8 years (in the water 365 days per year) and they've been fine, no corrosion to speak of.

I don't doubt what you write, based on your own real experience. If anything, I'd have expected any inherent problem to be worse in the Med. !t's very strange the reputation these props have in the UK. What can be going on ?

In my case;

Maybe 5 years intermittent immersion in fresh water with little use.

Quite black looking before immersion in salt water.

After 4 months in salt water, pink surface coloration in some areas of the hubs and blades and on soda blasting, some pitting on the hubs ( edit; the hub area of the outer part of the props, not the inner hub that is insulated from the outer and protected by the anodes).

Whilst in salt water, no shore power connected, galvanic isolator in place, no other boats nearby.

I'll take photos before launching and when out of the water in October.

 

[Portofino]

Might be to do with lack of zinc in the ambient sea
In the Med 100's + + + boats are packed into a smaller space each well anoded ( maintained ) so to speak -all fizzing away into to sea keeping the Zn ambient concentration high enough to protect them ?
Remember no tides washing through twice a day