Repairing Nicks below waterline

[joe_nj]

These photos show two of about 15 similar nicks in my boat's hull. These are the largest. The first one is 3/8" and the second one is 1/2" long before I grind the edges.

How do I repair these? Can I just do a Gel coat repair or do I know to put some epoxy or even glass and epoxy in their first?

You can also see some bubbles around the first one. I'm not sure what they imply about what's underneath. Should I leave them alone or open one up to look?

The boat is a '87 Cobalt 17BR

 

[QBhoy]

Gel coat repair kit be just fine. Maybe try and smooth off that second one though. It has a raised section. If you have the time, try and square and mask the edges with electrical tape, then once done leaves a nicer finish. Then if you need to, sand it down with some fine grit and polish/compound the crap out it.

 

[Grub54891]

I see more " bubbles" in the gelcoat around the first pic. That tells me that there is water between the gel and glass. You may find more knicks as time goes on. Are there more all over the bottom?

 

[joe_nj]

Grub54891
You got me wondering so I took my Protimeter Aquant moisture detector and measured the moisture at various spots along and across the hull and took a few more photos. The first photo (port 3) from the port side shows s darkened area in the center. In that area, the meter reads 8 to 12 on a scale of 0 to 15. I don't know why it's darker. In the surrounding areas, it reads 0 to 3. It doesn't take much moisture to register on the meter but I would have rather seen 0 than 12. I cannot get at that section from inside the boat to take a measurement or check for moisture there - it's beneath the deck and behind the stringer.

The 2nd (sb3) photo from the starboard side shows an area with similar readings. I don't know what the discoloration is on the 2nd photo.

Towards the bow and stern, I get no moisture readings.fore or aft of these spots and none above or below them. They are adjacent to each other, port to starboard and both are surrounded by areas with zero on small readings.

Banging with a hammer sounds solid.

I don't know how much of a safety issue I have with these readings. Any thoughts?

You can see that I have a lot of patching to do. At least West Marine said they will match Amazon's price on the gel coat kit.

This all comes at a time when my wife saw my brother-in-laws new Sea Ray 25' and now she wants a boat with a head.

 

[tpenfield]

Bubbles = Blisters

It seems that the 'nicks' may be the ones that have cracked open. Other are following in their footsteps.

You can Google "osmosis blister repair"

 

[Grub54891]

Yeah,sorry to say but each blister has to be dremmled out, filled properly and re gel coated. Then hope no more show up.

 

[joe_nj]

Wow! I took a look at osmosis blister repair. That's a lot of work, more time than I spend on the water in a year, and would take some skilled fairing. I've replaced the deck and have a gallon of epoxy and 10 yards of glass left so I have the supplies but it sounds daunting. It also looks like I can wait until the fall since I trailer the boat.


I wonder how many guys reading this would respond differently than I did on the question of a new boat. My wife took a tour of a new $120,000 Sea Ray and told me I should buy it. Instead, I'm looking for a 10 year old Cobalt - or fixing up my 30 year old Cobalt. How many guys would be enjoying that Sea Ray now and never looking back? Maybe I'm crazy.

 

[Fed]

This link http://www.norglass.com.au/file_download/19/Fibreglass_Info.PDF will give you a good insight into what's happening and how to fix it. Your action starts on page #3 and well worth the read.
You may have to source equivalent US products or they may be available locally for you.

 

[mr 88]

If you have the money and your wife is saying drop 120,000 I would be signing paperwork instead of dicking around with a 31 year old hull that is blistered out AND the wife doesn't want any part of it. If your balking ar 120g then cut it in half and buy one a few years old that you and the Mrs will BOTH enjoy. You only live once !

 

[joe_nj]

Fed. Thanks for that article - it's the best explanation that I have seen so far. Meanwhile, as Mr. 88 says, I'm shopping for a newer used boat.