Tuesday, 10 November 2015

2nd weed hatch and the “Sorry Bin”

Today miserable windy and wet weather contributed to our reluctance to leave the warmth of the cabin.  After several hours I became slightly “stir crazy” and started looking around for something to do.

The second weed hatch in the “sorry bin” hadn’t been checked since Waiouru was launched so that became the maintenance task for the day.  The “sorry bin” (AKA bow thruster locker) contains just about everything you will be sorry you didn’t have if something were to go wrong with a critical component on the boat.  For example; it contains the toilet self pump out kit and the porta pottie (both have never been used).  If we didn’t have them I’m sure we’d have a toilet problem (Murphy’s Law).

As you may have guessed the second weed hatch provides access to the bow thruster.  It was something I included in the boat specifications and I’ve been surprised by the number of boats that don’t have an access hatch.  I’ve also been surprised by the number of boats that don’t have grills over the ends to their bow thruster tubes.  I recall one boat with a bow thruster problem calling in to the wharf where were were doing the fit out having to be craned out to access the thruster (which was in the centre of the tube).  There was no access hatch and no grills on the ends of the tube.  The owner told us he usually had to replace the propeller every two years or sooner.

IMG_8608 The top of the weed hatch is the square white plate in the above photo.  To the left (partially obscured) is the bow thruster electric motor and the black bag to the right contains the porta pottie.  I positioned the bow thruster off centre, to the left (port) side of the boat.  The boatyard didn’t want to fit it in this location telling me it should be in the middle for equal thrust in both directions.  I insisted it go off centre for two reasons.

  1. The motor and weed hatch obstruct the clear space in the locker.  Offsetting it increased usable storage capacity.
  2. I disagreed with their belief that having it offset affected the thrust.  The water has to be pulled from one end of the tube and pushed to the other.  In my opinion the resistance was therefore irrelevant.  The thrust from the bow thruster seems to support my position.

Once the stainless steel securing screws had been removed I had to tap the plate with the club hammer to break the seal.

IMG_8607

Even though the top of the hatch is above the water level I’d made a gasket from rubber window tape to seal the hatch.  At this point I realised I’d made a false assumption erred in my judgement.  I had assumed that as the canal water is clear at this time of the year I’d be able to see the propeller.  I’d failed to remember the propeller is in a tube painted with black two pack epoxy.  The water was blacker than midnight.  On a more positive note, I was pleased to see there was no sign of the black epoxy degrading.  Upon feeling around the propeller I was even more pleased to find it clean of rubbish and the blades in good condition.

Everything was then reassembled.  I added some petroleum jelly to the threads of the machine screws before inserting them.

Jan will no doubt yawn and complain about another boring technical post but it was the only interesting thing that happened today.

4 comments :

Paul and El said...

Hi Tom
Caxton had a weed hatch above the bow thruster tube, I changed the prop through the hatch quite easily. My training as a gynecologist helped.
Paul

Rona Hawes said...

The most exciting thing today was you sending me a link to your blog!

Tom and Jan said...

So you must be the motorbike mechanic who did an engine rebuild through the exhaust pipe?

Tom and Jan said...

Rona
Jan knew it was going to be so boring she refused to proof read it😊