car wash cause corrosion?

[Flex]

Hi all. My old man has an old tinny which he bought second hand. and last week rinsing it down after an annual trip we noticed hundreds of corrosion holes along the inside of the bottom of the boat. all the holes where around the welded aluminum strip that goes along the bottom from front to back. now i assume these holes have been there for a while and we have never looked real close to notice them.

The boat only gets used once a year for 2 weeks and is always rinsed with a gurney afterwards. which has me thinking, maybe the previous owners have used a truck or car wash and the wash has sat at the bottom of the boat and caused the hundreds of holes? we've never used any detergent in the boat so i dont know what else could have caused it

anyone else seen this type of thing before? i cant upload a pic but theres litterally hundreds of small holes along the bottom, about 2-3mm across and 1-2mm in depth

[Luke G]

Not any sinkers down there? or hooks, swivels etc?

Cheers

[PADDLES]

luke's got it in one flex, i'd be looking for anything down there that's not aluminium. it's setting up a reaction with water sitting in the bottom of the boat. does the boat sit outside in the weather? does it get lifted at the front when stored so water drains freely out of it?

[Flex]

Its whole life since we had it, its been stored completely dry in a shed. we always lift the floor and gurney it every trip(which is only once a year, the boat never gets used otherwise). just seemed strange to have corrosion along the bottom and the entire length of the boat.

[Kleyny]

Ct 18 (truckwash) has a certain amount of acid in it. I have heard of it distoying wires under bonnets of cars/trucks. They put acid in it because they say truck drivers dont want to scrub only wipe and rinse.

neil

[Benny01]

they are pretty big holes for small time electrolosis. it will be some thing like the carwash as said that is causing it

[FNQCairns]

Could they by chance be those strange holes caused in the weld from the pratice of welding but over time look as if general corrosion caused them.

CT18 has a very nasty chemical in it (forget what it is called), quite dilute but ruins aluminium, things you learn when once a hoon with shiny mag wheels -not to mention the dirtbike.

I have been planing to pour a litre or two of an oil down the keel of my tinny from the front to combat corrosion, still searching for a suitable oil.

cheers fnq

[tunaticer]

Just wondering if your old man does ant handywork at home in the same shed. Something like occasionally grinding stainless or copper or brass or even steel.
My theory may be sparks will settle at the lowest point ie the keel and if it is damp or gets wet electrolysis can and will occur.

Jack.

[FNQCairns]

Thinking about this, any detergent will cause it if the boat is placed in a sheltered place before completly drying and without a good flush with bulk fresh water, another case of being loved to death?..I dunno.

cheers fnq