pictures are at https://www.dropbox.com/sh/e2obli3c7mv27di/AAA8aKllYMzmQg2HPNoo0-A9a?dl=0, one example at https://www.dropbox.com/sh/e2obli3c7mv27di/AAA8aKllYMzmQg2HPNoo0-A9a?dl=0&preview=P1040413.jpg
i have a blistered boat bottom, none look severe but i'm looking for what to do, videos for advice, etc... for how to fix it. as far as i can tell, i'm to dremel or "hard sand" out the blisters, put on west 410, sand again, put on interleux 2000, sand, vc17. i just want to confirm these are compatible products and i'm just looking for some how tos before i make a bad situation worse.
thanks
becki kain
To my very inexperienced eye (but I'm pulling our boat this December for a butt paint job), they look like poorly applied bottom paint rather than blisters.
Paul
so just sand off and repaint?
I don't see blisters but you appear to be missing the anode on the strut. That may have been the cause of the pitting. Blisters are best seen when you first haul the boat.
becki
looks like blistering (examples P21, P25, P17, P40) but certainly not extensive and none severe. Very typical - pea size, not dime or quarter size. If blisters they should shrink back on the hard and then reappear when whetted again (next haul.) Nothing critical (as in boat threatening.) To verify, pop a couple of the zits with a sharp pocket knife - they should oooze water if a blister, or will be hard or flake off if the cause is paint/prep.
The other areas are more of an issue to me than the slight blistering. Looks like underneath might not have been prepared, something foreign on the there when applying the VC, coat too heavy, or maybe temperature/humidity? The larger peeling areas you might carefully peel off and see if you can tell if there's anything incompatible left underneath them, just to satisfy yourself/identify why.
As far your paint sequence below, you have VC but what's your barrier coat? Make sure they are compatible and barrier overcoat is compatible. (Interlux website has a chart of compatible paints, or call them or your supplier.)
Some of the areas (many) appear to be old (P7) where the VC was applied over what had already peeled, was missing, and not repaired and faired/feathered out. The same might be true of some of the crazing. Nothing I see is going to hurt the boat from floating and sailing -- I have seen A LOT worse on floating graveyard boats that are still on the water after 30 years.
The deep cracking above the strut -- (where it has been sanded?) looks to extend into the substrate below? Is that fiberglass showing below VC or is it barrier coat that appears to have cracks with VC remaining in them?
Is your garboard plug leaking rusty water?
If you don't already, get yourself a GOOD DA sander with a vacuum attachment if you are doing repairs yourself.
k
Becki,
I wish my bottom looked as good as yours when I pulled it last July. I repaired around 475 blisters which is not unusual for my boat, I've done the bottom 7 times. I usually drill and fill, then sand and prime, followed by two to three coats of bottom paint.
You've got a few options here; the best is a barrier coat but you're talking some serious $$$, next if your planning on racing you'll want to make the hull as smooth as possible(lots of fairing and sanding), lastly if you're just going to sail or cruise then I'd just chip, sand, fill, and fair the bad spots, prime and paint.
Mark is right you need a zinc on your strut, I'm amazed your boat has made it 30+ years without one. It's easy just drill a hole the size of the zinc bolt dead center right through the strut.
becki is your strut possibly bonded?
Becki- just for an FYI- if a wet spot is a true osmotic blister, (caused by water penetrating the gelcoat) when you pop them, the water that drains out will smell like styrene/vinegar. Some of your spots could just be just water trapped under cracked faring and flaking bottom paint. I would leave most of the small circled spots (probably true blisters) alone. When/if they get bigger, grind, rinse, dry, then fair/fill, paint. Deeper ones may even need glass cloth patching.
Most of your issues look like poor fairing and paint application, (either applied over dirt, over incompatable sub paint, poor drytime, or applied to thick??? —causing bad adhesion/bonding/cracking issues. Just a guess without being able to poke at in person. All fixable by just working on/patching those areas.
the shaft was replaced when i first bought the boat, 6 years ago, and i'm wondering if the anode was just forgotten by the repair person. i just sent him a note.
Looks more like fairing or layers of bottom paint. What is the history on th boat? I ask because it looks like VC17 now, but was it something else prior and over laid wit VC. I see you are in Detroit. Freshwater, VC makes sense, but there is no way it would be as thick an application to show that much pitting.Freshwater also explains the sacrificial.
Becki I forgot to add re: a sander. You May already know this, but you can save a lot of time and sandpaper if you towel the VC off with acetone and sand just what's underneath that.
Even if your shaft was replaced, there doesn't seem to be any sign that there was anything on the strut. Of course you realize you don't want zinc in the Great Lakes.
OK Ken, what anode does Becki need, if any? I am a saltwater sailor, not freshwater, but I believe Becki might benefit by a magnesium anode on her strut?
Correctamundo mon ami
http://www.defender.com/html/zincs_info.html
It must be true, I read it on the Internet
And the reason for the magnesium anode is???
Quote from: tommyt on October 21, 2017, 05:58:38 PM
And the reason for the magnesium anode is???
Read the web link, but in short freshwater being less conductive you need a less noble metal anode than zinc or aluminum (for brackish).
IGNORE the fact that Defender used the term ELECTROLYSIS for stray current corrosion.
arrrrgh!
Arrrrrgh!!
AAAARGH!!!!
We are not splitting water into hydrogen/oxygen (electrolysis) with our boats. At least hope not.
good to know. i would have bought zinc, mistakenly . thanks Ken
also a LOT of the damage in the pictures was caused by westport marina, in lasalle canada, lifting the boat up with rocks in the bands. this was before i had the boat. they are also the reason i need to buy a cradle, the illegally kept the one that came with the boat.
Quote from: anaisdog on October 22, 2017, 06:49:29 AM
good to know. i would have bought zinc, mistakenly . thanks Ken
Something else I noticed, IIWMB I would have placed the shaft anode further forward. Just seat-of-the-pants it seems very close to the strut and you want to make sure there's no interference with water flow thru the cutlass bearing (water flowing is the lubricant/coolant.) I've heard of standards of 3x or 4x the diameter, or 6" from the strut. Some even put the anode at the hull end of the shaft (supposedly minimizes drag?) Just keep it away from the center third of the shaft to avoid the anode from introducing shaft whip/vibration.
k
Becki,
When you say they "illegally kept", you mean they stole your cradle?
Soda blasting is a great way to remove the existing bottom paint and start with a clean slate. There are several threads about that in this message board. In 2014, it cost us $1,700.
Steve
scgunner - it's a husband / wife yard. the wife said, many times, that i could have the cradle for free (this was in september after I bought the boat) . when my guy got there, with the trailer, the husband said i had to pay them money to load it and the summer storage fee in canadian cash right then, which my guy didn't have. they would not take a credit card or any other payment and never did the wife state i had to pay them for the time i DIDN'T own the boat.
and they lifted the boat, at least once, with rocks in the cradle straps. you can see the damage in the bottom paint.
QuoteSoda blasting is a great way to remove the existing bottom paint and start with a clean slate.
QuoteIn 2014, it cost us $1,700.
Just want to give a much less costly DIY option. A couple of club members used a pressure washer with coal grit to remove previous bottom paint. Looked like it worked well. Did make a mess but our parking lot / boat storage yard is gravel and the mess was quickly unnoticeable. They did this in the fall and waited till spring to apply a barrier coat and bottom paint.
Jim
thanks. what did they use for the barrier coat? thanks
Becki- this blog post on "blasting" may be helpful
http://cleanedbypete.blogspot.com/2013/05/sand-or-coal-slag-for-media-blasting.html?m=1
Quote from: Noah on October 24, 2017, 07:33:51 AM
Becki- this blog post on "blasting" may be helpful
http://cleanedbypete.blogspot.com/2013/05/sand-or-coal-slag-for-media-blasting.html?m=1
Mercy that post makes my eyeballs hurt. I wish I could edit and do a spell check for cleaner peter.
What's the roules on blasting and haveing to captchure runnoff? Only if their's runoff that gos directly to an waterway? Not if it percelates into gravell? I know that some yards have really clampped duun on DIY bottom wurk. Lickily my yard is opan 6 days a weak, closed Mundays (if you get my dreft.) ~~~~~~
k
Becki,
You need to find a new yard. It sounds like yard policy is based on the mood they're in that day, and they don't even seem to be in agreement with each other. I'd get my boat out of there pronto.
Jim,
If you tried that in the Peoples Republic of California you'd wind up in jail.
oh, i never stored with westport marina, the PO did. i am at edison boat club
Smart move!