Pettit Black Widow Testing and Evaluation Part Two

Stripping the boat's bottom

As I showed in PART ONE, the boat’s bottom is covered in years of old, gnarly, built up bottom paint. Having stripped a boat bottom by sanding, scraping and through the use of chemicals in the past, I know what a nasty job it is.

Old Antifouling Paint

Old Bottom Paint Buildup

The cratered, chipping bottom of the author’s boat shows the result of years of anti-fouling paint buildup. Refinishing to a smooth surface is hoped to provide speed and efficiency benefits, as well as an aesthetic upgrade. Kevin Falvey

That’s why this time, we called in the pros from All About Blasting to use soft ( glass) media to strip the bottom. All About Blasting uses the soft media, whereas other contractors use,” dustless” methods. There are drawbacks and plusses to both which we will explore in another article. Talk to your local blaster to see what choice makes sense for you.

Step one is to lay a drop cloth of 6 mil poly sheet on the ground under the boat, as we showed in Part One.


Next, the ” skirt” or “tent” of clear poly is taped to the boat and to the drop cloth. Then, air from a carpet fan or shop-vac run in reverse is introduced to the tent in order to inflate it.

Tented Boat 2
A tent is created by taping the clear film to the hull and to the plastic ground cloth. Shrinkwrap tape is used for good adhesion. Kevin Falvey
Boat Tented
Boat is tented and air from a shop vac inflates the tent. Kevin Falvey

Then, a completely suited up blaster enters the tent and begins the stripping process.

Prior to blasting, I measured my boat’s waterline at several key places in order to replicate it.I also took several pictures of the waterline. I wanted all traces of the old paint gone. However, your blaster can leave a 1/-inch strip of paint at the waterline for reference and more convenience if you choose.

Measuring waterliine
Taking measurements between the waterline and chine, strake or boot at key locations will allow the author to replicate the line after the old paint is blasted away. Blasting contractor can also leave some paint at the waterline by request, if desired. Kevin Falvey

A clean bottom, after blasting.

Blasted Bottom
The bottom has been blasted clean. Kevin Falvey

In part three we’ll fill imperfections before priming.

Pettit Black Widow
Pettit Black Widow Pettit Marine Paint