ON 805 - Replacement of Engines

ON 805 - Replacement of Engines Tony Merriman.

ON 805 was built in 1938 as the SAMUEL AND MARIE PARKHOUSE.She is a 46ft Watson class LB with special odifications to suit the conditions at Salcombe where she served until 1962. Throughout her service life she was powered by twin FERRY VE4 engines of 40 hp each but these were removed before sale in 1963 and her first private owner installed BMC NEWAGE "COMMODORE's of 52 bhp and these were still there when I bought her in 1972, I have already submitted a detailed article on the latest installation to the Life Boat Enthusiasts Society but Quinton Nelson uggested that I might prepare an abbreviated version for the interest of those members of HLOA who are not members of LBES.

Apart from an annoying number of minor oil leaks these engines served well until I had a heart attack in the summer of 2001 as a result of which I was unable to visit the boat unaided for nearly 8 months and they suffered from lack of maintenance. In June 2002 we sailed to attend the ex-LB rally at Fowey but shortly after leaving the Hamble a serious fault developed in the starboard gearbox and we returned to our mooring.

Spares were very hard to obtain so repairs were not completed by the time of slipping for annual refit in the spring of 2003. Trials were carried out alongside on re-launching when a completely different fault developed in the port gearbox. I considered fitting replacement boxes but the engines were as old asthe boxes and beginning to show their age so I thought my sailing days were over. In the meantime Frank Smith (former Coxswain of Salcombe LB and owner of ON 971 - JOSEPH SOAR) had undertaken to break two of the 48ft 6in Oakley class boats provided he could keep any useful parts. Among these were the 110 bhp Gardner 6LX engines from ON 1016 and he kindly offered these to me.

I was also fortunate in that Tom Lantau had been among my crew for the intended cruise to Fowey. He stayed with me and, as he is a Naval Architect by trade, spent the evenings assessing the feasibility of installing these engines and calculating the changes in trim and stability that would result. ON 805 entered the boatyard in September 2003 and work began immediately on the removal of the engine room `lid' and the old engines. The engine room - in which, owing to the small size of the COMMODOREs, it had also been possible to locate the heads and galley was then gutted. The engines had not been lifted for 40 years and some work was required on the boat's structure where it had been inaccessible and the opportunity was taken of painting the engine room.

The Gardners were removed from ON 1016 in early October and they were checked and run by a Gardner engineer before Frank and his crew delivered them to the boatyard and, once there, we could assess the problems which lay ahead. There were 4 major ones :-

(1) Both the FERRYs and the COMMODOREs had been offset from the propeller shafts by about 3 1/2 ins and raised by the same amount. The Gardners had no such offset but needed to be raised by about 7 inches.

(2)ON 1016 had large heat exchangers which relied on the forward movement of the boat to provide a flow of sea water. ON 805 had originally had the same arrangement but this had been removed and replaced with much smaller heat exchangers with raw water circulating pumps.

(3) ON 1016's exhausts discharged underwater through special valves.

(4) ON 805 had originally had dry exhausts up a funnel but these had been replaced by water injected exhaust discharging through the side above water. The Gardners had 24v starters while ON 805 had a 12v system.

The offset/rise problem was solved by bolting 4 sub-frames for each engine on to the existing bearers. Wooden mock ups were made and carefully positioned using plywood templates of the plan and fore-and-aft section of the engines. Finally the sub-frames were fabricated in heavy gauge steel being hot dip galvanised before being bolted in position with bracing plates between the inboard ones to increase general rigidity. This was so successful that eventual positioning and lining up of the engines was simple.

The cooling and exhaust problems were solved simultaneously. The cooling inlets were blanked off, as hey would have been inaccessible, and were replaced with larger ones ahead of the engines. Belt driven pumps were installed and stainless steel water njection boxes constructed so that both cooling water and exhaust discharged through enlarged skin fittings. Luckily the COMMODOREs had been fitted with arger heat exchangers than recommended and the cooling capacity of these was the same as those recommended for Gardner 6LXs so we were able, with but little modification to the pipe work, to use them.

Many solutions were considered for the electrical problem but, in the end, we decided to instal two independent 24v systems with a separate 12v domestic system - the latter being charged through a converter and change-over switch from either bank of starter batteries. The very heavy duty alternators required to operate the electrics of ON 1016 had been removed and smaller ones were supplied by Gardners and driven by the shaft that operates the
hydraulic gear change system. She was slipped shortly before Christmas 2003 and work progressed well until the yard's only mechanic, through no fault of his own, was involved in a serious road accident and was off work for several weeks and only working at half speed for even longer. Nevertheless the engines were lifted in in January 2004 and work progressed very slowly on the pipework and electrics. It was fortunate that the modifications to ON 805 included an enlarged engine room as, although the Gardners would have fitted in the more normally sized engine room, it might have been necessary to remove the gearboxes while actually lifting them in. Opportunity was also taken to carryout the annual anti-fouling before re- launching towards the end of
February when it became apparent that Tom Lantau's calculations had been pretty accurate!

Work was so slow that it was not until 24 June that she was fit for sea trials, We gave her about an hour at 600 engine rpm, the same at 800 rpm, at 1000 rpm and at 1100 rpm - the latter giving about 7.5 knots. She was then given 20 minutes at 1200 rpm and the same at 1300 rpm - giving just over 8.1 knots - compared with 8.003 on original engine trials in 1938. The only serious fault was a saltwater leak from one of the exhaust injector boxes and this was rectified in the next couple of days. Panic then set in in order to get her ready to sail for Fowey, via Salcombe, on 29 June. On the way to Salcombe both injector boxes failed but were speedily repaired by the Salcombe mechanic the next day. In the event Fowey was cancelled and we remained in Salcombe for 5 days where, in addition to JOSEPH SOAR, we were joined by MICHAEL STEPHENS - ON 838.

The opportunity was taken to carry out comparative speed trials with JOSEPH SOAR before returning to the Hamble, via Weymouth, on 5/6 July - the water injector boxes failing once again while on passage. On return to the yard we diagnosed that the damage to the boxes was caused by resonance so they were stiffened with stainless steel webs, given flexible mounts and their position slightly adjusted to relieve any strain on the flanges.

A 4-hour sea trial as later carried out and the problem appears to have been solved. Fuel consumption appears to be 1.6 gph for each engine as opposed to 1.3 gph for the COMMODOREs but cruising speed is about 7.5 knots as opposed to 7, in terms of mpg, the change is very small. The feeling that the engines are being perated well within their capabilities (they can be adjusted to give 147 bhp) gives a tremendous feeling of confidence with a large reserve of power in hand at normal cruising speed. I owe a debt of thanks to too many people to mention them all in this abbreviated account and to mention only some would cause offence to others. They know who they are and know how grateful I am for their help, encouragement and support.

&mbsp;