To Peel or not to Peel?

I remember the first time my computer got a 'virus'.  It was my freshman year of college and the dawn of the computer age.  One day while typing away on page nine or ten of a fifteen page essay, the screen on my computer suddenly went black while white squiggly lines danced across it.  "What the...?" I said under my breath in confusion as I started frantically hitting keys.  A half hour later one of the "techie" guys on our floor confirmed it:  my computer had a virus.  "What do you MEAN my computer has a "virus"?!?" I asked accusingly.  I literally could not wrap my head around the fact that a piece of equipment could get 'sick'.  It just didn't make sense.

While I don't remember the first time I heard about boat blisters, I remember having a similar reaction.  "What!?!  Boat's get BLISTERS?!" I mean, that just seemed weird.

A "gelplane" for gelcote peeling

The short answer, is yes:  boats can get blisters.  Like a blister on your heel, a boat blister is a raised bubble filled with fluid.  They are certainly not uncommon, nor are they the end of the world, but you do want to take care of them for they have the potential to hurt you and, if left unattended, they only get worse.  Blisters on a boat (usually) occur below the waterline when the sneaky water molecule permeates the paint, gelcote and (ultimately) the fiberglass.  Water and fiberglass react, causing a little science project otherwise known as "osmosis", to occur on your hull.  I'm no expert, but from what I understand when fiberglass gets wet, it gets weak and you should fix it. To fix it you must remove all the layers of paint and gelcote in order to expose the fiberglass underneath.  There are a number of ways to do this; paying a professional to do it with a handheld powered planing tool is the more expensive (and significantly easier) one.

When we did the marine survey on our new boat, the surveyor uncovered some areas of moisture in both the deck and the keel.  While he saw no indication of blistering of the hull*, he strongly suggested we peel the bottom of the boat down to the fiberglass to see what we found.  The owner of the boat yard said the bottom looked okay, that we might be able to get away with sanding and a few more coats of bottom paint but he said there was definitely "something" going on.

Hmmm...what to do?

Peeling and repainting is not a cheap project (about $12K for a 44 foot boat), but luckily we negotiated the price of the boat down to compensate for this.  Never prone to skimping when it comes to caring for our boat(s); instead of "pocketing" the saved money, we decided to peel the hull.  Agressive?  Perhaps. While nary a blister was uncovered, there was an area of wet fiberglass in the keel that needs to be cut out, re-glassed (essentially built back up) and faired (smoothed out).  It was a good thing we peeled.  We now know exactly what we are dealing with and the 'problem' is easily fixed.

Now that the fiberglass is exposed, we let the boat "dry out" for about thirty days (our hull has very little moisture in it, so thirty should suffice) with periodic fresh water rinses in between to draw out moisture (yeah, seems counter-intuitive, but it works).  The yard will then do weekly checks with a moisture meter to determine the dryness of the hull.  Once the hull is dry, they will re-apply the gelcote and bottom paint.  If you paint your boat before you let a wet hull dry out properly, you will have a virtual blister party on your bottom.  No one wants a blister party on their bottom, no one.

Asante with her bottom peeled.

A closer look at her bottom.   Cheeky monkey!

Moral of the story:  a blister on the bottom of a boat isn't going to respond to a band-aid any more than a computer virus is going to respond to an antibiotic. 

Here's a more scientific and explanatory article on the blister issue for those interested.

Love,
Brittany, Scott & Isla

* Like bourbon and whiskey, not all boats with osmosis have blisters, but all boats with blisters have osmosis.