Stern drive barnacles!

[chrisgil]

I have just lifted my (new this season) Marex with Mercruiser engines and stern drives for winter storage. The boat has been in water from mid April and the hull is clean as a whistle but the stern drives are horrid!
All will be cleaned tomorrow but my problem is that Mercury warranty is invalidated if any form of anti foul is used on stern drives (at least as far as the casing is concerned) and I am obviously keen to avoid that problem.
I can at least put something on the props without this problem…propspeed?
It maybe I have no choice but to make sure everything is cleaned properly at the end of each season until warranty expired but am interested to know what anyone else with stern drives has experienced and if there is a ‘magic potion’ I could consider.

 

[jointventureII]

I put a binbag over mine when not in use (in the water), but I can reach it from the platform. A bit of a faff, my arms get wet up to halfway between elbow and shoulder.

It's about 30 years old so I've no warranty to void and as such have covered it in velox, but the bag has had a major impact by eliminating sunlight. It's been in the water comjng up to 2 years and I've lost 1 knot off the top speed.

I don't think the binbag will be enough without antifoul so for you, it might require some manual cleaning in the water mid season

 

[ss2016]

Yes, I have the same problem. 6 months in the water and it looks like this. The Hempel Hard Racing does a pretty good job on the bottom but the drive and tabs after 6 months in the water look like this. The back of the boat is not so good but I doubt that slows it much. The props were polished to 'as new' last winter and I sprayed the drive with Hempel Ecopower. Useless, a waste of money.
I think most of the lost performance is due to the dirty props since much of the growth on the drive is above the bottom of the boat where there is not much water flow.
Even after jet washing there are lots of tubeworms and shells and I push them off one by one with a plastic or wooden scrapper. I am hoping someone will have a good suggestion. It's too far down for a bag to be practical.

It's a VP drive on a Sargo.

 

[moresparks]

Without questioning your dealer who supplied your Mercury Warranty … The section below is taken from the latest Mercury Installation Manual :-

Antifouling Paint
IMPORTANT: Corrosion damage that results from the improper application of antifouling paint will not be covered by the limited warranty.
Painting boat hull or boat transom: Antifouling paint may be applied to the boat hull and boat transom, but you must observe the following precautions:
Important Information
IMPORTANT: Do not paint anodes or pressure wash anodes or the MerCathode System reference electrode and anode, as this will render them ineffective as galvanic corrosion inhibitors.
IMPORTANT: If antifouling protection is required for the boat hull or boat transom, copper base paint, if not prohibited by law, can be used. If using copper based antifouling paint, observe the following:
• Avoid an electrical interconnection between the Mercury MerCruiser product, anodic blocks, or MerCathode System and the paint by allowing a minimum of 40 mm (1‑1/2 in.) unpainted area on the transom of the boat around these items.
NOTE: The sterndrive unit and transom assembly can be painted with a good quality marine paint or an antifouling paint that does not contain copper or any other material that could conduct electrical current. Do not paint drain holes, anodes, MerCathode System, or items specified by the boat manufacturer.
NOTICE:
Washing the MerCathode assembly can damage components and lead to rapid corrosion. Do not use any cleaning equipment such as brushes or high‑pressure washers to clean the MerCathode assembly.
Do not wash the sterndrive unit with a power washer as this can damage the coating on the reference wire of the MerCathode assembly, if equipped, and increase corrosion.

 

[Scubadoo]

I would only worry about the lower half of the drive, the bit in the water flow. I can't see painting antifouling suitable for aluminium drives e.g. seajet 034 would invalidate warranty, and moresparks post above seems to confirm this.

 

[chrisgil]

Without questioning your dealer who supplied your Mercury Warranty … The section below is taken from the latest Mercury Installation Manual :-

Antifouling Paint
IMPORTANT: Corrosion damage that results from the improper application of antifouling paint will not be covered by the limited warranty.
Painting boat hull or boat transom: Antifouling paint may be applied to the boat hull and boat transom, but you must observe the following precautions:
Important Information
IMPORTANT: Do not paint anodes or pressure wash anodes or the MerCathode System reference electrode and anode, as this will render them ineffective as galvanic corrosion inhibitors.
IMPORTANT: If antifouling protection is required for the boat hull or boat transom, copper base paint, if not prohibited by law, can be used. If using copper based antifouling paint, observe the following:
• Avoid an electrical interconnection between the Mercury MerCruiser product, anodic blocks, or MerCathode System and the paint by allowing a minimum of 40 mm (1‑1/2 in.) unpainted area on the transom of the boat around these items.
NOTE: The sterndrive unit and transom assembly can be painted with a good quality marine paint or an antifouling paint that does not contain copper or any other material that could conduct electrical current. Do not paint drain holes, anodes, MerCathode System, or items specified by the boat manufacturer.
NOTICE:
Washing the MerCathode assembly can damage components and lead to rapid corrosion. Do not use any cleaning equipment such as brushes or high‑pressure washers to clean the MerCathode assembly.
Do not wash the sterndrive unit with a power washer as this can damage the coating on the reference wire of the MerCathode assembly, if equipped, and increase corrosion.

Thank you for this….I will double check my warranty which I thought (and advised by dealer) banned any sort of treatment. However, if I can use non conductive paint maybe that’s the answer……otherwise lots of barnacle scraping

 

[chrisgil]

I would only worry about the lower half of the drive, the bit in the water flow. I can't see painting antifouling suitable for aluminium drives e.g. seajet 034 would invalidate warranty, and moresparks post above seems to confirm this.

Thanks…will investigate Seajet 034