I have written before about fishing line and propellers don’t mix here, we now have had another lesson on that subject.
In Sydney it is legal for recreational fishermen to fish from public wharves provided that they adhere to some requirements, Social behaviour, keeping their environment clean and boats have right of way. The majority of fishermen keep respect their privilege.
The picture at left illustrate the results of a prop line mix on the sail drive of G-whizz.
There are times however when a combination of lack of awareness on behalf of the boat master and the fisherman that creates a situation proving that fishing line and propellers don’t mix. Our recent refresher lesson was quite a bit less expensive than the first and a lot easier rectified.
Returning to the GFS pontoon from our mooring our torqeedo powered dinghy did not notice a fishing line deployed from the adjacent Bay Street public wharf. Modesty prohibits me from naming the driver of the dinghy at the time. The result is pictured to the right. Illustrating that fishing line and propellers don’t mix.
The first photo represents a substantial amount of money, the second not so, fortunately no damage to the shafts or seals in either case.
Please read an update to this post, it is about the rectification process undertaken to the unsatisfactory repairs described below.
Or the alternative title to Cast iron keel could be:
Why we love our cast iron keel – A high maintenance affair!
G-whizz, as with all Elan 340s with the deeper 2.1 metre keel is fitted with a composite keel, cast iron foil with a lead (“Elephant’s foot”) bulb. I am not qualified to make assumptions on the benefits of various keel structures, nor do I fully understand the methods used to protect the cast iron in a marine environment. The Broker who sold G-whizz, they were the original Elan agent in Australia, said the reasoning behind the cast iron keel was that it allowed for a finer keel profile, the cynic in me thinks that it allows for a finer profit to the manufacturer. Maybe it is a combination of both.
G-whizz was launched 13 years ago and has performed exceptionally well in those years, requiring only regular maintenance and no repairs due to design issues. However for the past 4 or 5 years the cast iron keel has required a bit more attention than just a pressure wash, sand and repaint during the annual bottom service.
The following photos compare the condition of the keel following a pressure wash just after coming out of the water, the deterioration in 2 years is noticeable.
For the past few year the shipwrights have patched the keel using processes that are a bit beyond my comprehension, however the the cast iron keel continued to deteriorate between the annual services. I must say that the treatments were never promised to be a long term fix, only something to try and get through to the next service – in this regard the were somewhat successful. This year we bit the bullet to do something a little more permanent, we got two quotes from two different yards. These yards suggested different methods:
One; to soda blast the keel and epoxy.
Two; to wire grind then chemically treat the keel.
Quote two was half the price of one. and is the treatment we went for. I guess the success of this decision will be measured when G-whizz comes out of the water next year, although reports from the diver who cleans her on a regular basis will be most anticipated.
Motoring on the way to the shipyard for this bottom service G-whizz was struggling to get to get over 6 knots though the water under motor at 2000 rpm, on the way back to the mooring she was exceeding 7 knots at the same rpm, I wish I took more notice of wind condition on the first journey, but on the return run the was a gentle 3 to 5 knot wind just off the the bow, quite an improvement.
As mentioned earlier we were told that the Cast iron allowed for a fine keel profile, maybe the photo to the right illustrates that.
We are looking forward to our next race, that for a number of reasons is not coming fast enough, just to check G-whizz’s performance against her traditional competitors.
For those with a better technical mind in these matters than mine, the base treatment of the corrosion on the cast iron keel was Feronite, which I believe to be manufactured (or distributed in Australia) be Boatcraft.
I guess this whole process give us an insight into the trials and tribulations of those that have steel boats.
What is described above did not wor as intended read an update here.