Monday, April 24, 2017

Autopsy of a failed thru-hull fitting

Overboard is to the left, hose connects on the right

A thru-hull is a fitting that is used to connect the outside of the boat to a hose on the inside.  They are usually used for water intake and overboard discharge (In and Out).  Bronze is used below the waterline because a failure there could be catastrophic.  Plastic is usually used above the waterline on fiberglass boats.  Tortuguita has 25 fittings above the waterline and 15 below.

In order to prepare the boat for gelcoat work, all the plastic thru-hulls were removed and will replaced with new ones when the work is done.  

I really didn't suspect there were any problems but had quite a surprise and can now explain some mystery water leaks.

This is a thru-hull that is for the forward shower drain pump.  Since we don't use these showers, we didn't notice any significant leaking.  However, when a wave would splash up, it was apparently leaking in through the crack and had been seeping into the boat.

By the yellowing of plastic, these were old cracks
On the other forward shower drain, I found a broken 'tail' under the hose clamp and a crack at the outer hull.  Privilege likes to hide things like thru-hulls in hidden compartments that require quite a bit of work to access.  Since I never needed to replace one of these hidden thru-hulls, I had no reason to dig into these false compartments.

Many of the failures are from over-tightening the big nut on the back.  This cracks the plastic at the outside edge.  This particular thru-hull was also cracked at the inside edge which is usually caused by vibration or pressure fatigue.

New supply of 25 TruDesign fittings
Cheap thru-hulls like the ones that were just removed are made of nylon.  My research led me to only 2 brands of decent replacements.  Forespar (US) makes a product out of a proprietary plastic called Marelon.  TruDesign (NZ) makes their thru-hulls out of fiberglass reinforced nylon.  In this part of the world, it made more sense to go with the New Zealand brand.

Besides having a boat that is not leaking, the really cool thing about this whole project is now I know of more secret compartments to store things.

Monday, April 17, 2017

The Workbench

The normal boatyard workbench, pallet style. (Australia 2014)
When working on a boat, it is important to have a table or the like where you can put  things that are being worked on.  In a boatyard, that usually consists of something scrounged like a pallet or boards and if you are lucky, maybe a sawhorse or two.

Marina Island is different.  People are here for years working on their boats, and we may be also.  After all, we made the investment to buy a car and we really do like it here in Malaysia.

If you happen to be carrying carpentry tools on the boat, it is easy to knock out a table or bench.  Our woodworking tools reached the end of their lives in Mexico and since the voltage here is 240 volts, anything that I buy will be all but worthless in the US.

I had the opportunity to buy a workbench from Andy on SPRUCE that was originally built by Jeff.  The price was a reasonable $90 US and it was even equipped with a vise.  In the end, I will end up selling it to someone else and recoup some of the cost.

Even rolling on wheels, it was a hard push
The really nice thing about the bench is that it has locked storage underneath.  Instead of chucking tools in the car at the end of the day, everything can be stored in the bench.

This thing is really heavy.  It has to weigh 250 pounds and is built from some type of local tropical hardwood.  A forklift would have been nice to move it from the shed area to Tortuguita but since there wasn't one, we examined all the options to move it about a hundred yards.  We found an engine hoist on wheels sitting around and commandeered it to do the heavy lifting.

Workbench, vise, all out of the sun and rain in our catamaran garage

Now we have a proper workshop under Tortuguita which is so much better than the rickety pallets that we have used in the past.

My only regret is that I can't keep it.  Sure would look nice at home in the US.