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Sunday, 29 September 2013

The Foul Story - Barnacles, Ultrasonics & The Facts From Cousin Glen

Some weeks back I wrote (here) of the difficulties we had experienced with barnacles fouling the sea water inlets on Crystal Blues in estuarine waters.

Keen to find a solution, we started to investigate the new ultrasonic antifouling systems - these use a low power transducer attached to the hull, constantly exciting the hull with acoustic energy which (we are told) prevents algae and barnacle growth.  One leading manufacturer, Ultrasonic Antifouling Ltd., claimed that preventing algae growth also prevented barnacles, because the barnacles fed on the algae. I was somewhat suspicious of this claim -  I just didn't see how barnacles (which never move) could effectively feed on the algae on the hull.  See the story here, on their promotional email.

Cousin Glen at Wilson's Promontory, Victoria
So we turned to cousin Glen Burns, our oracle on all things related to marine biology.  His informative and generally hilarious response is presented here :

"Anyway...in answer to your question, barnacles do NOT rely on the slime/algae growing on the (hull) surface, they are (as you suggest) filter feeders. They don't actually suck water into the body as clams, oysters (ie bivalves) do. Barnacles are actually arthropods not molluscs, so they have legs like crabs. Their legs are hairy and  modified into filter feeding appendages. They open their shell and reach out with their hairy legs to "sweep" any organic particles in to their mouths. You can watch them do this... if you have the patience to sit and watch a barnacle. Who said marine biology wasn't exciting!  Lots of particulate organic matter in estuaries and harbours means lots of food for barnacles and therefore a pain in the bum for boaties, constantly trying to keep the little critters from fouling hulls, intakes etc.

Searching For A Mate - Scary
So what do you do about it? Antifouling paint, either toxic or ablative obviously works on the outside. Scrape them off, dig them out, regularly replace bits...there is no easy answer. I'd be really interested to hear how the ultrasonic system works. What's that saying about "Build a better mousetrap and the world will beat a pathway to your door"...I reckon the same goes for barnacles...come up with a cheap, easy, environmentally friendly solution and boaties everywhere will be on bended knees in thanks!!    By the way, just another tidbit of information for you re barnacles. Being arthropods they practice internal fertilization. 

videoNow, being cemented to the substrate,  barnacles obviously can't get up and go looking for a mate so the penis is actually capable of extending out and over to neighbouring barnacles to facilitate insemination.  Which means that if you're a barnacle, size really does matter!  The further you can reach with your penis the more individuals you can mate with and thus pass on your genetic information to the next generation. Which is why the humble barnacle has the longest penis (relative to its body size) of any animal on the planet! Depending on the species,  the penis may be 10 times the individuals body length. So Ley, thanks goodness Neil isn't a barnacle or you'd be dealing with a schlong nearly 20 metres long!!"

Thanks Glen ... I think.  Maybe too much information.   Anyway, I have noticed that the "algae is barnacle food" claim is not repeated on the company website.  Equally, the product may work really well, even if we don't really know exactly why.  So we'll probably try it soon - stay posted, and please feel free to add your comments or opinions to this post.

Sunday, 22 September 2013

Things That Work For Us # 4 - Caribe C10x RIB Dinghy

Taking our Iban friends for a fast ride on Sungai Tulai, Sarawak
Explaining our cruising lifestyle to land lubbers, we say that we do own a "car", it just happens to travel on water!  We drive the dinghy to the shops, out for dinner and visiting friends.  With the Tohatsu 18hp engine we travel quite long distances, exploring rivers, coastline and small islands where we cannot take Crystal Blues.  Our first experience with inflatable boats was an almost-new PVC Zodiac that came with the boat. It self destructed quickly, slowly deflating daily.  At a boat show in Los Angeles we spotted the Caribe boats, built in Venezuela, and ordered one for delivery to Sydney in 1999.  It had proper Hypalon tubes and a double skin fibreglass hull.  We loved the dry and fast ride it gave us - fitted with lights and extra fuel tanks that boat covered thousands of miles.

Arriving For School On Sungai Tulai - Children From The Longhouse Rumah Lidam
 As my friend Jim Cate would say, it was always "ridden hard and put away wet", but it never complained.

On the rivers in Sarawak (Borneo) it worked incredibly hard for years, and I do remember 12 children (and more) being delivered to "school" on Crystal Blues on most days, for weeks on end.

We patched it when necessary, had canvas covers made in Thailand to protect the tubes, and it served us faithfully for 14 years.  Hats off and congratulations to Caribe.

This year it started to need more frequent care, and we found ourselves applying frequent patches - the Hypalon fabric was failing at last.  Contemplating a new dinghy was daunting.

A Cracked Anchor & Fake Rocna's

Cracking Up!
Planning an ocean crossing, early this year we sent our Bruce anchor and chain to Bangkok to be galvanised.  Tick another job off the list we thought ...... wrong.

Whilst the chain came back looking shiny and new, our anchor came back showing a significant crack above one of the flukes. The Bruce has been great, 15 years of sterling service for us and 8 years on the boat prior to that.  This crack was not evident before it was galvanised - but better to discover it now than when it inevitably fails under load.  Click on the photo at right for an enlarged view of the crack.

So the search was on for a new anchor.  After the usual wasted days of reading and research, we decided to buy a galvanised 33kg Rocna anchor.  It has a number of advantages over the Bruce and other more traditional anchors, including greater holding power, the roll bar for instant setting and it is self lauinching.  

Is It Fake Or Is It Real ?

Rocna anchors are readily available in Phuket, but we just couldn't work out which was an illegal copy and which anchor was the real thing.  We spoke with many resellers and came away more confused.....did a real Rocna have impressed lettering or raised lettering - we saw both types.  Each dealer claimed to have the real Rocna, and warned about fakes every where else.  With rumours everywhere, we found even the Rocna website warned of copies, and the variance in pricing was quite remarkable.

So we contacted the Rocna head office in Canada, first by email and then on the telephone, to clarify the situation.  How could we pick the fakes ?