More Hole Cutting

Andy marked out another nine holes in the engine compartment this morning.  This has given me plenty to do.  On the port side are holes for the Hurricane heater air inlet and exhaust, along with the exhaust for the Beta engine.  I’ve cut all the holes through the exterior of the shell as high above the waterline as reasonably possible.

You may have read Bruce’s comment (nb Sanity) on our last post regarding the positioning of the Hurricane inlet and outlets.  Unfortunately I already cut the holes.

(L-R) Hurricane air inlet, Beta exhaust outlet hole (covered by gaffa tape) and Hurricane exhaust outlet.

On the starboard side are holes for the calorifier pressure relief valve (PRV) and the bilge pump outlet. 

(L-R) ¾” Bilge outlet and ½” PRV outlet. Partially covered with gaffa tape because the brass fitting has yet to be sealed.

There are now two pairs of holes going through the engine bulkhead to the back cabin.  They are for the hot and cold water plus the central heating system.

Starboard ½” H & C connectors to calorfier

Port ¾” connectors to the Hurricane central heater.

Apart from the two smaller holes which were cut with a cone drill, most of the holes were cut with a hollow core circular saw bit fitted into an electric drill.  My technique with the circular saw bit is to slightly oscillate the drill so that only a quarter of the saw teeth are actually biting into the steel at any moment.  The saw also gets dipped into a bucket of water at regular intervals to keep it cool.  Care must be taken towards the end of the process or the saw bit can catch in the hole which results in the drill going around the bit.  Not much fun if you are holding onto the drill!

The skin fitting for the Hurricane air inlet is made of aluminium and secured with three screws.  I drilled three 3.6mm holes and then threaded them with a 4mm tap. Next I smeared construction adhesive on the rear face of the inlet before screwing it in place and wiping off the excess adhesive with white spirits. This will provide a water tight seal around the inlet.  The remaining fitting are brass and will be sealed and tightened tomorrow.

Our Beta 43 engine may arrive at the beginning of next week and will be the last major component to go into the engine compartment.