options for fixing this keel rash

[LosCoons]

Good Evening Gents,
Over the last few months I've been practicing small fiberglass repairs on my 170 in an attempt to get it ready for paint one day.  How should I fix this damage on the keel?  It's probably from years of running the boat up on sandbars and oyster beds.  I've had the boat for about 4 years and I think I'm the third owner.  I've been using the boat a ton the last couple years so this needs to be sealed up and fixed.  This will be done on the trailer.  Do I want to sand it down around the area and lay resin/mat in strips to build this back up?  In one of the pictures you can see where i've fixed a couple other small spots that same way that were chipped off.  I have an orbital, a grinder and a bunch of glass materials.  Thanks!

[RickK]

Do you see any holes or is it just the abrasion action you described that you are seeing, that removed the gelcoat?
If no holes, I might use an orbital and some 80 grit and sand down the area to expose about 2" on both sides of the keel.  If all looks good (no holes) I think I would mix up some gelcoat and brush it on the area to seal the glass.  The gelcoat and the new bottom paint is enough to protect the boat.

If there are deep holes then I would need to see closer pics to help you.
 
I had a crack in my keel that I could stick a screwdriver into - now that needed some more intense rebuilding with glass and then gelcoat. What I'm seeing on yours I would just re-gelcoat after roughing it up a bit (80 grit) and repaint with anti foul - looks like you have ablative bottom paint on it right now.

[LosCoons]

Thanks Rick.  I'm going back out to start sanding later this week so i'll get some closer pics.

[LosCoons]

Ok so it's been about a month and I've made some progress with this.  Not as much as I'd like but we've had a lot of rain lately and I finally (temporarily) moved the boat from my storage unit to my back yard.  This has since turned into painting the outside of the hull.  I'd like to do some painting this weekend if i get the rest of this bottom paint sanded off.
This is after being patched with resin and filler and sanded some.

more scrapes that need to be faired-

this is not quite my final pic from today - got some more off the front. 

planning on putting a primer and then a 1 part interlux on this hull.
When i sanded under the transom, it almost looks like a repair was done but i'm not sure what to think of it.  this is how it looks sanded at the same level.

[wingtime]

You might have had a very slight hook in the hull where the transom sags a tiny bit.  May have been that way since it was built.  Boats, especially of that vintage are far from perfect.  Especially for a popular model like the 170 where zillions of them were popped out of the molds causing the mold to warp etc over time.  Also they popped many molds from the original plug, and when the plug is gone made new molds from a existing hull...  Also the plugs and molds were made by hand so by nature they are not perfect.  It's not like today where you can design a hull with off the shelf cad software.  Email it to a company with a five axis router to cut you out a PERFECT hull plug out of foam. 

[LosCoons]

fixing keel rash turned into paint pretty quickly.  i faired all that rash and ended up taking the paint off of the rest of the boat. 


next i put a coat of grey primer on the hull - using interlux prekote and brightside.



this is what it looked like after 1 coat of grey.

i ended up buying a can of white primer and doing another coat on top of the grey after that.  didn't get a pic of it but i put the white primer on then sanded the hell out of all of it until it got smooth.  these next two pics are of the actual interlux brightside. i'm using steel grey. 




i'm doing the bottom with the same paint and color, i just needed to practice some when i wasnt laying on my back.  this is my first rolling and tipping, or painting of any boat. 

[Capt. Bob]

Looks good! 

[RickK]

Nice job! Is the paint ok for below the waterline?

[LosCoons]

So I really don't know the answer to that.  I asked a few people about bottom paint on a trailered boat and was told it's not necessary. But is that with the assumption that I have gel coat? This is a topside paint and the boat will not sit in the water overnight.

[mshugg]

Every manufacturer of topside paint seems to advertise as above the waterline only.  Yet, when pressed they often admit that the paint can be used on a trailer boat for limited immersion.  EMC/Quantum, the manufacturer of the paint I’m useing, said that there was no problem useing the paint on a trailer boat for day trips and in water for up to a week as long as it is rinsed/washed with fresh water after.  Again the concern seems to be fouling organisms.

Check with your manufacturer, but paint is less porous and more flexible than gel coat.  You should be fine for a trailer boat.

[LosCoons]

Interlux tells me "Topside paints when submerged for several hours will allow water to permeate causing blisters and then peeling. Brightside should not be subjected to submersion for more than a few hours at a time." So I guess I'm back to the drawing board and have 2 quarts of brightside that I need to try and return to stem some of the cash hemorrhage related to this painting adventure.     I'm also reading that bottom paints have to be kept in the water or they stop working? -but topside paint can't be kept in the water?  So this must mean that all trailered boats need to have gelcoat?  This entire paint situation is confusing to say the least.

[mshugg]

I painted a wooden kayak with Interlux Brightsides.  It spent many several hours submerged and never showed amy sign of permeation, blisters or any other issues.

You can always coat your bottom with epoxy graphite mix.  Racers have been doing it for years.

[RickK]

I used EMC paint on the sides of my boat - beautiful paint. It too, said above water line.  I did the bottom of my boat with epoxy primer and then VC epoxy paint and ran it up passed the water line by a few inches. Then I painted the sides with the EMC paint.

[mshugg]

This is what Tom at Quantum wrote in response to my enquiry about painting the bottom of trailer boats:

“If trailering and dry sailing the boat, using Quantum99 below the water line is fine as long as you rinse off with fresh water after. A long weekend to a week is the max Quantum99 should be left in salt water continuously.”

[LosCoons]

Thanks for all of the input guys.  I'm going to proceed with painting the brightsides all over the hull right now.  I already have the paint and worst case, I'll just put some bottom paint over it.  Really I'm in a time crunch to get the boat back in the water for a few trips this month.  Here's an updated pic with 2 coats of topside over the primer - I figure the least I can do is provide some more pics and reading material for all of you who are in-between rebuilds right now and chomping at the bit  to get started again