estuary prowler Posted October 8, 2008 Share Posted October 8, 2008 I have a Quintrex 435 hornet trophy which I bought second hand about 2 years ago. The boat is a 2001 model. When I purchased the boat it had a bit of bubbling of the paint on the gunnels which I believe is possibly some sort of electrolysis. Wasnt to fussed about it and still not but just recently the boat has been taking in a bit of water so I filled the hull with water at home and was then alerted to see that on the bottom of the hull water was slowly dripping out of several little corrosive looking pin holes. Does anyone know what might be causing this??It definately looks like some sort of corrosion or something is slowly eating away at the hull. Not happy!!!!! Any help / advise would be greatly appreciated. Cheers Link to comment Share on other sites More sharing options...
achjimmy Posted October 8, 2008 Share Posted October 8, 2008 I have a Quintrex 435 hornet trophy which I bought second hand about 2 years ago. The boat is a 2001 model. When I purchased the boat it had a bit of bubbling of the paint on the gunnels which I believe is possibly some sort of electrolysis. Wasnt to fussed about it and still not but just recently the boat has been taking in a bit of water so I filled the hull with water at home and was then alerted to see that on the bottom of the hull water was slowly dripping out of several little corrosive looking pin holes. Does anyone know what might be causing this??It definately looks like some sort of corrosion or something is slowly eating away at the hull. Not happy!!!!! Any help / advise would be greatly appreciated. Cheers Mate that doesn't sound good, we have a 2001 Quintrex as well, there was an issue with earth grounding on certain models at one stage. Perhapsyou shoul pull the floor up and see what it is like underneath? Link to comment Share on other sites More sharing options...
copafisher Posted October 9, 2008 Share Posted October 9, 2008 ....it had a bit of bubbling of the paint on the gunnels .....on the bottom of the hull water was slowly dripping out of several little corrosive looking pin holes. Cheers My 2004 stacer bowrider has similar bubbling. Most are around locations where the paint protection has been broken by drilling etc or possibly isnt so good. Huey indicated that salt gets under and sets up corrosion. I dont wash/wax too frequently, which might help slow it down. When i bought mine I was told to regularly check under florr for stuff that might corrode hull from inside (hooks, sinkers etyc). Apparently lead sinkers are particulary bad for causing holes. Have a chat to Huey or local dealer. Link to comment Share on other sites More sharing options...
ORES Posted October 9, 2008 Share Posted October 9, 2008 Yes I have a 2007 5.25 model and its allready getting corrosion and its due to 2 different types of metals such as s/s(low grade), lead and steel nuts and bolts, washers, hooks and sinkers toching the raw alloy(unpainted). Im thinking of ripping out all my floor and tanks to coat the inside ofthe hull with an antifaulling paint that is usualy used on the outside. Atleast you dont have to worry about that odd sinker,washer or nut that falls under the floor. Link to comment Share on other sites More sharing options...
Dreamtime Posted October 9, 2008 Share Posted October 9, 2008 Yes I have a 2007 5.25 model and its allready getting corrosion and its due to 2 different types of metals such as s/s(low grade), lead and steel nuts and bolts, washers, hooks and sinkers toching the raw alloy(unpainted). Im thinking of ripping out all my floor and tanks to coat the inside ofthe hull with an antifaulling paint that is usualy used on the outside. Atleast you dont have to worry about that odd sinker,washer or nut that falls under the floor. I think I would be leaning towards an epoxy rubber paint for under the floor. This will cure two problems. Firstly, it will add some soundproofing to the hull and secondly, and more importantly, it will provide the insulation barrier you are looking for to prevent sinkers and the like degradating the integrity of your hull. With most anti-fouling paints they have a "life" limit with regards to the time applied before immersion occurs. Some may be as little as 24 hours, but there are some that are good for up to 3 months (top dollar) before the integrity of the preventative additives begin deteriorating. I actually haul down my boats from the slipway when the antifouling has just become "touch" dry. This may be within 2 hours of the final coating. Food for thought. Cheers Mariner Link to comment Share on other sites More sharing options...
warnie Posted October 9, 2008 Share Posted October 9, 2008 Aluminium hulls can benifite greatly from and more so in cases where there is allready visible evidence with reaction to dissimiliar metals... ie paint bubbling in area of s/steel bolts through rod holders by appling sacrificial anodes to areas under the floor which are readilly available in boat stores i have four tear drop anodes fitted under floor to my boat and have actually two fitted to the trailer and regular inspection confirms that all anodes fitted along with the standard sacrifical anodes to the motor are doing there job by that i mean as in sacrificing them selves in favour to the aluminium.. and consequently i have negligible evidence of any reaction anywere to the boat maybe that may be a first option to help stop any further deteriation.. Also I have been reliabily informed that leaving falling tree leaves to rot in the bottom of an aluminium hull is a bad cause of what you have described however don't ask me the reason's to why as i don't know.. Cheers Warnie... Link to comment Share on other sites More sharing options...
flatty hunter626 Posted October 9, 2008 Share Posted October 9, 2008 When i bought mine I was told to regularly check under florr for stuff that might corrode hull from inside (hooks, sinkers etyc). Apparently lead sinkers are particulary bad for causing holes. anything like hooks, sinkers swivels.... all that crap is very bad for an aluminium hull i hav seen the corroision issues it causes in the tinnies at work, ungry warnie is on the ball with the anodoe idea though. Link to comment Share on other sites More sharing options...
ORES Posted October 9, 2008 Share Posted October 9, 2008 How do you fitt one of these? Do they run power??? Cheers Link to comment Share on other sites More sharing options...
copafisher Posted October 9, 2008 Share Posted October 9, 2008 i have four tear drop anodes fitted under floor to my boat and have actually two fitted to the trailer and regular inspection confirms that all anodes fitted along with the standard sacrifical anodes to the motor are doing there job by that i mean as in sacrificing them selves in favour to the aluminium.. Thanks Warnie, I check the engine ones regularly but had not thought to fit to the hull or the trailer (to protect its gal coating). Will get some asap, local retailer has them from 400g-2.5kg, what size did you use. As Stucatz indicated what is the best way to fit, I obviously dont want to drill holes in the hull but want best contact between anode & hull. Could silastic/glue around for the hull but theres probably better ways, maybe even a glue that enables minute electric current ? Thanks again Steve Link to comment Share on other sites More sharing options...
a boat Posted October 9, 2008 Share Posted October 9, 2008 Hi, there are two main forms of corrosion that can affect Alloy boats. Corrosion or in more light case called oxidation is due to two different metals reacting. Pretty much all alloy boats have some oxidization and this causes the paint to bubble, salt we get under the paint and make it worse. If left untreated it can cause bad corrosion and having two dis-simialr metals make it even worse. The other form is electrolysis and this is casued by the presence of stray electrical current whihch in turn runs thru the boat and casue paint to bubble and the alloy to be eaten away. With your boat I would make sure the wiring is up to spec and the boat is not being earthed. Then I would remove the floor and make sure there is no sinkers / hook swivel or the like under the floor. Yes running an anode will help on a moored boat, because it will corrode first and are easy to attach to a hull (an do not need any power) but on a trailer boat there is no much need if the other two causes are not there and the paint is kept in the best shape as possible. Hope this helps, Huey. Link to comment Share on other sites More sharing options...
copafisher Posted October 10, 2008 Share Posted October 10, 2008 ...the boat has been taking in a bit of water so I filled the hull with water at home and was then alerted to see that on the bottom of the hull water was slowly dripping out of several little corrosive looking pin holes. Does anyone know what might be causing this??It definately looks like some sort of corrosion or something is slowly eating away at the hull. Est p, 'Unpainted aluminium hulls are susceptible to intermatallic corrosion if lead sinkers or brass fittings are left in contact with the hull in the presence of salt water, resulting in perforation of the hull.' (http://www.vmrgladstone.org.au/metals.html). I am still not sure of causes of the bubbling I am getting under paint but will look at fittings/rivets etc and proably have to remove paint and protect/refit fittings where they seem to be the cause. Pretty complex subject and lots of theories/causes etc. FYI, this was simple info on corrosion at http://www.duroboat.com/experience/Aluminu...dCorrossion.htm Link to comment Share on other sites More sharing options...
estuary prowler Posted October 10, 2008 Author Share Posted October 10, 2008 Thanks everybody for your advise, I will be having a good look this weekend for possible causes. Cheers Link to comment Share on other sites More sharing options...
Day's Fishin Posted October 10, 2008 Share Posted October 10, 2008 This happened on my trailcraft around the bung .I suspect It was from the drilling to fit the bung.Like a lot of manufactures their work leaves a lot to be desired when it comes to the finishing off jobs! They give these mundane jobs to apprentises who couldn't give a dam because its not their boat. Regards Jeff. Link to comment Share on other sites More sharing options...
pappy Posted November 4, 2008 Share Posted November 4, 2008 Hi, there are two main forms of corrosion that can affect Alloy boats. Corrosion or in more light case called oxidation is due to two different metals reacting. Pretty much all alloy boats have some oxidization and this causes the paint to bubble, salt we get under the paint and make it worse. If left untreated it can cause bad corrosion and having two dis-simialr metals make it even worse. The other form is electrolysis and this is casued by the presence of stray electrical current whihch in turn runs thru the boat and casue paint to bubble and the alloy to be eaten away. With your boat I would make sure the wiring is up to spec and the boat is not being earthed. Then I would remove the floor and make sure there is no sinkers / hook swivel or the like under the floor. Yes running an anode will help on a moored boat, because it will corrode first and are easy to attach to a hull (an do not need any power) but on a trailer boat there is no much need if the other two causes are not there and the paint is kept in the best shape as possible. Hope this helps, Huey.hi i have a little bit of paint bubbling on my boat and you say not to have the boat earthed how is this possible when the motor is earthed and bolted to the boat even the steering cable earths the boat and motor all my wiring is run to buss bars and not connected to the hull . how can i insulate the motor from the hull.thanks Link to comment Share on other sites More sharing options...
arpie Posted November 4, 2008 Share Posted November 4, 2008 (edited) Funnily enough, I was talking to a bloke about this during the week!! Seems that if you don't turn off your boat battery after an outing (it should have a separate 'turn off/isolating' switch, rather than just being attached permanently to the electrics), it can lead to electrolysis/corrosion, by putting that current/earthing thru the hull. It can show up initially as "surface bubbling" around the small clips for the travel cover. Roberta Edited November 4, 2008 by Roberta Link to comment Share on other sites More sharing options...
a boat Posted November 4, 2008 Share Posted November 4, 2008 Hi, on alloy boats we fit a teflon board in between the hull and outboard that isolates the two. Also the engine has rubber mounts between the mid-section and transom brackets that bolt to the hull, so you should not have any current going to the hull for the outboard. Boats that hav ehe boat as an earth for the electronics is. On trailer boats, that live most of the time out of the water, corrosion by stray curretn is not a big issue and the paint bubbling is caused by salt getting under the paint. With alloy boats the paint layer is the main barrier to corrosion and once that has been drilled or scratched you will get this. Best thing to do is clean and re-paint any areas that go like this. Cheers, Huey. Link to comment Share on other sites More sharing options...
p o ylop Posted November 7, 2008 Share Posted November 7, 2008 that was the reason i got rid of my last tinny just could not beat the corrosion it just keep getting worse as the years rolled on i had owned it for 12 years and was second hand when i got it I replaced it with a poly 4.1 have had it for 4 years now and all still good. ask me again after it turns 12 to see if i still have it Link to comment Share on other sites More sharing options...
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