More lessons learned Prop maintenance

More lessons learned 

Prop maintenance

Copyright (c) Froo Gal
2014, All rights Reserved

We had Froo Gal lifted and 'scrubbed' yesterday. The scrub was a pressure-wash of the hull below the waterline. She had been in the water for nearly 18 months and a few months ago had picked up a line around the propeller. We'd taken photos of the prop underwater (with a GoPro) and found that the incident had taken a few chunks out of the edges of the blade, but it did not look too bad.We were rather surprised by two things: first, the prop was almost entirely covered with almost a centimeter of growth. Second, the 'slight' damage to the prop seemed to have caused corrosions sites that had gone completely through the metal (aluminum) in several places. The sacrificial anodes would do nothing to prevent this, as they were aluminum too. Even the zinc anodes that we replaced them with would do very little better. The boat lift operator recommended that we paint the prop with Velox.We also were pleasantly surprised by the price of a replacement prop by a local supplier adjacent to the boat yard -- less than 250GBP book price less a discount, with free delivery within a week. We'll probably buy one at least as a space, but will also investigate more robust folding props.A little research today shows that the growth was likely to have been a type of Coral worm possible tubeworm that is not native to the UK. They seem to like metal.Whilst Velox seems to be the right answer, being frugal the crew of Froo Gal will want to look at alternatives, especially the cheaper DIY versions.A yachtpals.com article suggests some interesting approaches: polishing, greasing or applying zinc oxide in lanolin or cod-liver oil. These seems useful for an outboard or trailer-sailer, but not very durable. Propshield is an example of the boat branded products along these lines. Yachtpals.com suggests that a trip to the chemist to grab some nappy rash cream will save you lots of money. Looking the Propshield prices they may well be right.'Pukka' alternatives to Velux include International Trilux Prop-O-Drev (an aerosol -- spray can -- delivered product), Volvo Penta Teflon prop anti-fouling and Propspeed. It is difficult to judge what would work best for us.

Copyright (c) Froo Gal
2014, All rights Reserved

Boating forum contributors suggest anti-fouling plus greasing; candle wax, Owatrol oil, CRC Soft Seal (silicon based), two-part clear, or clear polyurethane lacquer, but there seems to be a definite foolproof answer. This may be because conditions are diverse, so solutions need to be tuned to your mooring and sailing location or there may be no real solution, saving regular scrubbing. We have a snorkel set and wet suit ready in case.A word of caution. Please think of the environment and the law, including local regulations and by-laws when considering your solution.We will also scope out cheaper options to a lift and scrub. Many yacht clubs and marinas have scrubbing piles that can be used during spring tides. We have a pressure-washer, so this is a frugal option for us in the future. Understand the difference between cost, price and value!