Most folks know that barnacles can cause a bit of havoc when they attach themselves to the bottom of their boat, especially in the wrong places. I did another tour through the boatyard last week and discovered one cruising boat that needs to read this installment. The photos below show some of the wrong places where barnacles can really cause some serious damage if left in place after launch. Let me explain the potential problems, and my own easy solution.
In the photo above, we see the raw water intake strainer for the boat's engine. More than 50% of the strainer is covered by attached barnacles. This is guaranteed to affect water volume getting to the engine and through its cooling system. Symptomatically, this will manifest itself as an engine that runs too hot at high rpm.
Let's see what the next photo shows.
The above photo is a water discharge, not sure what for but it really doesn't matter, its almost totally plugged. A clogged drain if you will. Its going to cause something to overflow into the boat.
Let's look at one more:
The above photo shows a cutlass bearing case just forward of the propeller. In this case the prop shaft exits at the trailing edge of the keel and the bronze fitting that holds the cutlass in place has cast in scoops port and starboard that draw water into the cutlass to cool and lubricate it. Both scoops on the fitting on this same boat are totally clogged with barnacles. On this boat, replacement of the cutlass bearing is a MAJOR job. Also, if the cutlass bearing actually burns out, it's probably going to cause damage to the propellor shaft. Another major job which on this craft would involve removal of the rudder before the shaft could be pulled out for replacement. Were talking thousands of dollars here to get this fixed for the sake of a few barnacles restricting water flow.
OK, so how to prevent all of this? For the boat in the photos, assuming damage hasn't already occured, a thorough scraping and cleaning of all the barnacle infestation is step one, and that's going to mean getting up inside the through hull fittings and I would recommend removal of the sea strainer to check for growth behind it. Once cleaned out, I use a medium sized artist paint brush to get up inside the through hull fittings with anti-foulant paint. Apply liberally, but in the case of the strainer, not to the extent that the paint actually clogs the holes in the strainer. Same thing for the cutlass scoops, totally coat inside the scoops with anti-foulant, but don't restrict the water flow with globs of paint.
Ignoring these steps is going to be really expensive to fix. Check your boat out before this years launch.