June 13, 2018

Boat bottom blues

When we bought Borealis in early winter we knew her chipped, cracked and loose bottom paint was going to take time and money to fix before we got in the water in spring...we just didn't know how frustratingly long that process was going to be.

The good news is that after months of weather and contractor delays, we are finally close to launching. 



Borealis has been out of the water for at least 18 months, so the boat's bottom paint was very dry and flaking and chipping in many areas. In addition, while sanding the previous owner thought he'd accidentally sanded through the bottom paint and into the barrier coat, and so to protect the fiberglass hull, he used an epoxy resin over large areas of the hull. Those patches didn't react well with the next layers of anti-foul bottom paint and were cracked and peeling.

West Systems epoxy boat bottom peeling paint

Our dealer, broker and surveyor all recommended that we soda blast the bottom to the fiberglass and start fresh, but cold and wet weather in the Mid-Atlantic this winter and spring meant the work didn't happen until mid-May.

After the soda blasting, several weekends of nonstop rain in the DC area once again held up our progress since we struggled to find weather windows long enough for us to apply the paint and let it dry before the next shower, but we slowly got it done.

Hallberg-Rassy 37 on jackstands in boatyard after soda blasting

Sailboat hull after soda blasting

Before paint, we tackled any large chips in the fiberglass, especially the area down the centerline from stem to stern where there were large voids in the fiberglass (where the two sides of the hull are joined together). We used a two-part 3M Marine High Strength Repair Filler, which worked well to fill the voids but had a very short pot life of only a few minutes before it hardened, so we made lots of very small batches and worked across little sections of the hull at a time.



3M Marine Filler on hull centerline


Hull pits pinholes after sodablasting

We also fully removed the caulk from the seam between the keel and the hull, since it was cracked and falling out on one side of the boat. After scraping and sanding the area, we filled the void with 3M Marine Adhesive Sealant 5200 (and let it dry for a week before painting over it).

3M 5200 on hull and keel joint

After drying overnight and a quick sanding of the 3M Marine filler, we put on two coats of white Pettit Protect two-part barrier protector, which exposed hundreds of tiny pinholes in the fiberglass. These are often only surface pinholes and not serious cause for concern, but we wanted to fill and seal them before moving on.


Hull pinholes after barrier coat

We were recommend Pettit EZ-Fare, another two-part epoxy that worked very well for the project; it had a much longer pot life of 15 - 20 minutes and had a thin enough consistency that allowed us to cover the holes with a light, smooth layer that didn't require much sanding.


The following weekend, we tackled another layer of white epoxy barrier and finally a layer of grey epoxy barrier to ensure full coverage. The last coat of barrier paint requires a hot coat of anti-foul bottom paint on top while it's still tacky, so the two coats bind and dry together for maximum protection.

Hallberg-Rassy 37 after sodablasting and barrier coat paint


We finished with two coats of Pettit Trinidad Pro black anti-foul bottom paint...for anyone counting that's six layers of paint on the boat!

It's taken a lot of time and effort, but we feel confident now that the bottom is in great condition for the water.

Hallberg-Rassy 37 after soda blasting barrier paint antifoul bottom paint

We aren't quite done yet; this week we will have the jack stands moved so we can repeat the entire process on the unpainted areas. We also have a few more large items on our to-do list before we splash: replacing the prop's cutlass bearing and shaft seal, and waxing the hull.

Fingers crossed for more good weather!

1 comment:

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