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We have a small GRP boat that we intend to use on both sea and inland. She will spend a lot of time out of the water on her trailer, but will also be afloat on a saltwater marina for several weeks. I am in a quandary about anti fouling. She is old but the gel coat is in excellent condition.

 

Any advice is welcome.

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57 minutes ago, Jane Cartridge said:

We have a small GRP boat that we intend to use on both sea and inland. She will spend a lot of time out of the water on her trailer, but will also be afloat on a saltwater marina for several weeks. I am in a quandary about anti fouling. She is old but the gel coat is in excellent condition.

 

Any advice is welcome.

If you plan to leave it in a marina for more than a couple of days ENSURE that you have plenty of anodes fitted - Trailer boats rarely have any anodic protection and mooring in a marina makes in a necessity.

Assuming you are outboard powered, make sure that you have anodes on the prop, the skeg and somewhere to protect the leg.

As you are using both fresh and sea water you will need a 'compromise' set of anodes (Zincs for seawater and Magnesium for fresh water) which will be 'Aluminium', otherwise you will be changing anodes each time you change 'waters'.

Zincs will give you no (very little) protection in fresh water, and Mag's will fizzle away in 'days' in Sea water.

 

Had ours Anti fouled last year with Black* "VC Offshore with Teflon" over the top of grey "Primocon"

 

https://www.international-yachtpaint.com/en/gb/boat-paint-products/antifouling/vc-offshore-eu

 

Works in Sea water, Fresh water and Brackish water.

 

Bloomin expensive (about £400) but 'quality costs'

 

* Other colours available

 

 

16-10-19h.jpg

Edited by Alan de Enfield
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31 minutes ago, Alan de Enfield said:

If you plan to leave it in a marina for more than a couple of days ENSURE that you have plenty of anodes fitted - Trailer boats rarely have any anodic protection and mooring in a marina makes in a necessity.

Assuming you are outboard powered, make sure that you have anodes on the prop, the skeg and somewhere to protect the leg.

As you are using both fresh and sea water you will need a 'compromise' set of anodes (Zincs for seawater and Magnesium for fresh water) which will be 'Aluminium', otherwise you will be changing anodes each time you change 'waters'.

Zincs will give you no (very little) protection in fresh water, and Mag's will fizzle away in 'days' in Sea water.

 

Had ours Anti fouled last year with Black* "VC Offshore with Teflon" over the top of grey "Primocon"

 

https://www.international-yachtpaint.com/en/gb/boat-paint-products/antifouling/vc-offshore-eu

 

Works in Sea water, Fresh water and Brackish water.

 

Bloomin expensive (about £400) but 'quality costs'

 

* Other colours available

 

 

16-10-19h.jpg

What's the point of anodes of a GRP hull ?   On props & skegs yes but GRP isn't going to get electrolytic corrosion.

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4 minutes ago, WotEver said:

Fully covered in Alan’s second paragraph. 

No it's not, only the bit about the prop. skeg & leg. The OP has a GRP cruiser and was advised to fit lots of anodes. Alan said :-    "If you plan to leave it in a marina for more than a couple of days ENSURE that you have plenty of anodes fitted - Trailer boats rarely have any anodic protection and mooring in a marina makes in a necessity."

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I'm a bit hazy about anodes - they are attached to metal bits to stop the water corroding them? hence sacrificial, the corrosive chooses the anode over the OB leg or whatever. BUT why is it so important in a marina when the OB will be raised out of contact with the water?

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Sorry to go back to my original post - if the boat is out of the water regularly and not afloat for more than a few weeks at a time, can I not just pressure wash the hull in between? She's a tiny tiny little boat 5.5m 0.4 draft so not much hull to deal with :)

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1 minute ago, Jane Cartridge said:

I'm a bit hazy about anodes - they are attached to metal bits to stop the water corroding them? hence sacrificial, the corrosive chooses the anode over the OB leg or whatever. BUT why is it so important in a marina when the OB will be raised out of contact with the water?

If your outboard is tilted clear of the water, then that's fine. Few outboard powered boat in marinas seem to have their engines tilted.

 

If you have any 'hull fittings' that are in contact with the water (we have 11) then each of those needs to be bonded and connected to an anode - the anodes are not to protect the GRP but ANYTHING metallic.

 

This shows an anode on the GRP which would look to be doing nothing, but internally it is "bonded" (connected by copper cable) to the sea-cock on the forward toilet.

 

 

small.jpg

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1 minute ago, Alan de Enfield said:

 

If your outboard is tilted clear of the water, then that's fine. Few outboard powered boat in marinas seem to have their engines tilted.

Well, if I may say so, that is ill advised. Just call me Mrs Fussbucket.

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4 minutes ago, Jane Cartridge said:

Sorry to go back to my original post - if the boat is out of the water regularly and not afloat for more than a few weeks at a time, can I not just pressure wash the hull in between? She's a tiny tiny little boat 5.5m 0.4 draft so not much hull to deal with :)

 

As far as anti-foul is concerned - Yes you can (but make sure you don't forget as left on too long and it can 'etch' into the gell-coat.

 

You still need anodes tho, when you drop the leg, the prop is in the water and you can / will get cathodic corrosion.

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3 minutes ago, Alan de Enfield said:

 

If your outboard is tilted clear of the water, then that's fine. Few outboard powered boat in marinas seem to have their engines tilted.

 

If you have any 'hull fittings' that are in contact with the water (we have 11) then each of those needs to be bonded and connected to an anode - the anodes are not to protect the GRP but ANYTHING metallic.

 

This shows an anode on the GRP which would look to be doing nothing, but internally it is "bonded" (connected by copper cable) to the sea-cock on the forward toilet.

 

 

small.jpg

Thank you, clear and helpful.

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2 minutes ago, Alan de Enfield said:

 

As far as anti-foul is concerned - Yes you can (but make sure you don't forget as left on too long and it can 'etch' into the gell-coat.

 

You still need anodes tho, when you drop the leg, the prop is in the water and you can / will get cathodic corrosion.

Leg, prop and skeg?

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4 minutes ago, Jane Cartridge said:

Leg, prop and skeg?

 

The 'leg' is the section between the power-head (engine) and the anti-cavitation plates.

The paint is always (?) scratched off the skeg due to coming in and not tilting until you are on the beach - without paint it needs more anodic protection.

 

If you look at the picture, there is a 'lump' bolted onto the top of the anti-cavitation plate, and in front of the prop is a 'ring' held on with two bolts, these ar both anodes and need replacing fairly frequently

 

Outboard Motor Installation Guide - How to Install an Outboard Motor for  Your Small Boat

Edited by Alan de Enfield
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5 hours ago, Jane Cartridge said:

I'm a bit hazy about anodes - they are attached to metal bits to stop the water corroding them? hence sacrificial, the corrosive chooses the anode over the OB leg or whatever. BUT why is it so important in a marina when the OB will be raised out of contact with the water?

An outboard will usually have an anode under the cavitation plate next to the prop.

As for leaving the outboard in the up position,this is not recommended because someone mooring behind you may not realise that your leg sticks out perhaps 3ft and give your outboard leg a rather expensive clout.

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I can confirm that GRP boats do have anodes . I have them on the outdrives , the trim tabs and the bow thruster.

I use  aluminium anodes that are suitable in fresh or salt water. 

Magnesium anodes for fresh water will not last long in salt water. Zinc anodes for salt water may be ineffective in fresh water.

 

I used Seajet  031 which I bought locally . Coverage is 10m2 per litre .  I used a primer from the same manufacturer  to ensure a good bond and avoid any reaction . It was about £60 per 2.5litre tin.

 

20200151.jpg

 

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10 hours ago, Alan de Enfield said:

Thankyou - some folk read and cannot comprehend what is presented to them.

 

Perhaps it was the "lots of anodes" part that caused the confusion. The prop (shaft?), outboard leg and skeg wouldn't really require "lots" of anodes, just 3 which are replaced regularly.

Edited by blackrose
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14 hours ago, Mad Harold said:

An outboard will usually have an anode under the cavitation plate next to the prop.

As for leaving the outboard in the up position,this is not recommended because someone mooring behind you may not realise that your leg sticks out perhaps 3ft and give your outboard leg a rather expensive clout.

Fair point but we are on finger pontoons.  The main hazards a people who moor far forward and leave their pulpits and anchor rollers for me to walk into ;) 

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4 hours ago, Jane Cartridge said:

The main hazards a people who moor far forward and leave their pulpits and anchor rollers for me to walk into ;) 

My wife's pet hate on the marina in Plymouth where we keep our sailing boat, usually they are about head height She has been known to tweak their springs to push them back in the berth !

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  • 1 year later...
On 28/09/2020 at 09:26, Jane Cartridge said:

We have a small GRP boat that we intend to use on both sea and inland. She will spend a lot of time out of the water on her trailer, but will also be afloat on a saltwater marina for several weeks. I am in a quandary about anti fouling. She is old but the gel coat is in excellent condition.

 

Any advice is welcome.

 

We are all in a quand in Derry about anti foulup paint, (Hereinafter the letters AF will be used in all legal posts). It's just a side effect of owning, skippering or even just contemplating using a small to medium size boat of any description!

 

If there is one type of job or reposibility I never got right and caused me more grief in my life than almost any boa related activity, it was the dreaded Anti foulng task. I've really got it seriously wrong almost every time I opened a tin of AF paint. So the following rant and advice should be ignored:

 

1/ Sell the boat just after it has been pressure washed and cleaned!

 

2/ Read the instructions on the AF paint tin, then ignore them. They are written to make the job sound easy, alas it's not easy or simple if you want to get it right, or wrong if you do not like the owner of the boat you are painting.

Serious note: Take note that some types of AF do not like spending too long out of the water, they were designed to fail to increase sales figures!

 

3/ Preparation, preparation and preparation, they are all important. If you get it wrong by using the wrong primer, failing to clean off any tiny traces of grease from grease monkey  finger prints, you will become the laughing stock of your marina or canal lovers club. Paint that falls off really does not work.

 

4/ Stir the tin, let it it rest, then stir it again and never stop stirring until there is a risk of a whole in the can.

Serious note: Never try and use a spoon to stir a 2.5 liter tin of AF paint. Just steal your significant others Kenwood mixer and extension cable when they are not looking!

Another serious note: Never ever, (Much more serious in financial terms), buy 20 liter tins of anything except alcoholic drinks, if you are intending to decant that paint into a smaller tin. That's one big fork up, as it takes all day to correctly stir a big tin of AF paint and the typical Kenny mixer will not reach the bottom of the tin anyway.

 

 

5/ Stir the tin again just before application or post punch up with the new Kenny mixer owner.

 

6/ Don't be too concerned about the colour of any AF paint. The little critters, grass and slime could not give a flying dinner fork which colour you have used. I've even mixed colours of left over paint, just to save money. That resulted in a few negative comments from the boats owners about the vomit yellow AF job, which resulted in my team being banned from a small yard in Florida. The lovely illegal girl from way down South, (My team leader), could not stop laughing for days, because we had been well paid in advance! 

 

 Serious note to self: Google Orca or whale attacks on small boats in Scottish locks or tidal waters, cos some pods of killer whales have had very bad experiences with twits and fully qualified idiots in small to medium canal boats. Orcas are very fast when they get upset and have been filmed deliberately ramming a yacts rudder causing serious damage. Best advice I can offer if you come across a pod is to start the engine and TURN SLOWLY AWAY FROM THEM, just in case they have lost a calf in a collision with an ignorant twit of a boat driver. 

  Back on the old beloved AF rant: Google whale attacks and colour of AF paint, as there has never been any type of boat attacked that was painted pink, with black and yellow stripes ?? I'm not going to use Vomit yellow again, as it make my crew sea sick.

Off topic special note: Wash hands after using AF paint with some type of solvent, but put out your cigarette first.

 

7/ Once you have been conned into buying the latest tins of AF paint from your local marine stealership, make sure the first 2 coats are with the hard scrubbable type, NOT the ablative dissolves away version. Then read up about how important it is to use a lot more paint along the waterline and high flow areas like just behind the prop. So once the scrub up paint has dried fully and been inspected by every twit in the yard that makes adverse coments about vomit paint, overcoat it with 2 coats of ablative rub off stuff special offer paint. Then finish off the following day with another 2 coats along the waterline and on the rudder. So the waterline will need 6 coats of AF paint, after the primer.

 

8/ Don't rub the paint off with the traveling lift or crane straps, use plenty of carboard to protect your biblically expensive paint job.

 

9/ Once the salvage boys have refloated your pride and joy because you forgot to check the stuffing box had been repacked and greased correctly, read the instructions about how long or often the hull should be wiped down to allow the Orcas or Haggis hunters to fully appreciate just how great an AF paint job you have been in charge of. 

 

10/ Last of the ten AF commandments, but not least, buy the best possible very common type of major brand AF paint available, then sell it after failing to pay off your credit card. Contact me off list for how I make my own illegal AF paint that really does work for at least 2 years plus. Nah, I might as well tell you all, IT'S WILCO WHITEWASH, plus 100 ml of Sainsburys or Tescos, (Always use major brands only), CAYENNE PEPPER. Then I add a few other off list special powders, or crush up 100 Cipro antibiotic pills, (Be careful as some Orcas are allergic to Penecillin and Cipro), so have 2 ANA kits or a pair of type 1 diabetes crew nearby, as they will know what to do when you test a pill by doing something stupid like swallowing it without the doctor saying it's a good for drug resistant clap!

  Finally do some off list research into what I think is called Palmatate or Palmatey cream base, (No it's not in bubble bath mixes). That stuff will be difficult to find, but fairly cheap as it's used in a lot of different cosmetic products that I use on a sailors drag queen event, as it's a real good lipstick ingrediant.

 

Kind Regards

 Cdr Noah TNLI 

 

Sole survivor of the Starry Night delivery crew, may the other 5 great crew members rest in peace. Only the body of the owners brother was recovered. I placed a used AF  paint brush on his coffin, along with 2 medals for bravery whilst serving in the Royal Navy. We both made it into the same liferaft, but I had time to get my Noddy suit on before Starry Night sank, alas he did not. That was one bad night before we were picked up by a fishing boat. All the crew abandoned ship, BUT for some reason the first liferaft did not inflate correctly, or sprang a leak. The bow collision bulkhead saved my life, as we were T boned by a large bulk carrier nearly 1K miles SW of Ireland. That bulkhead allowed me enough time to get out of my bunk and grab my own grab bag with the survival suit before I had to leave through the forward cabin deck hatch. We effectively sank in less than 5 minutes, not that I had time to look at my watch. The bulk carrier never stopped and would have been unable to help anyway, as it was dark and a full gale was blowing. The bow of Starry Night, (Red and Green Nav light), was visible for some time until we were blown too far away. It's possible that the crew of the bulk carrier thought they had not sunk us cos of that Nav light being clearly visible at close range. 

Edited by TNLI
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