Paulyne J

Hi, I have a 50ft trawler built in Tassie by the Tompson Bros in 1984. I was wondering if anybody knows anything about these guys and there boat building. I want to remove some bulkheads that create the hold for cray. This is in the centre of the boat, one I want to remove completely and the other to the stern 500mm. I can see all the structure but plans would be a real asset. It would be good to find out any info re Tompson Brothers.

Hi Flathead The Guys that built the box do all types of marine boxes, they were not as familiar with the Capital as say a Twin disc but they were confident with the build and have been helpful but not definative with what the cause is. I have had the boat around 12 months. The rebuild was done after four months. It was complete the old box was rebuilt the heat exchanger was sent away by them and reconditioned new hoses and hydraulics no expense spared. They are prepared to supply the new larger exchanger. When neutral is selected it is hard to maintain, it slips into gear unless you find the exact spot, I will check the range again on the weekend but I am sure that I already have checked the range. The temperature is a very rapid increase, smell pressure drop and temperature increase all in 2-5min more like 2 though. I dived on the boat and checked everything and I was able to turn the large shaft and prop in neutral. The PSS seal and the keel shoe re shaft and alignment was done at the same time as the box. The water flow is separate to any other cooler on the boat with its own pump and flow out of the side of the wheelhouse, I am sure there is no blockage to the intake. Thanks for your suggestions, it is very helpful to hear your perspective. I feel the clutches are slipping after reading what you have suggested. What do you think? I am thinking to have the valve rebuilt or replaced with a new one given the neutural issue / the possibility this is the cause and while that is being done I will plumb in the new heat exchanger. Thanks so much for your advise. The problem has been troubling given the lack of confidence in heading deep sea after I have done so much work to make sure that the boat was bullet proof. Many thanks great advice.

Hi Flathead, Thanks for the thoughts, The intake filter lines and heat exchanger are all new or reconditioned. The Hydraulic lines are new. The box including the pump were reconditioned less than 100 hours ago. The fluid I changed and went to a far heavier one with no change to the problem. I like your ideas in general but the 3 below are very possibly the cause. Clutch packs not the same as the origional Shift cables/shuttle valves are not moving all the way - clutch not fully engaged and too hot. Trolling valve jammed or not reconnected properly. I do not drag nets the boat is for private use, the problem only comes when I start to push above 6knts, the pressure drops and the heat increases to a point that we loose drive. If you stay at 6knts it will go all day. We are doing about 1600rpm at 6, it would be good to have some more speed, before the rebuild we could get 8-9knts easily now we can get it for 10 minutes and we are out of action. Given your ideas re Clutch Pack, Shift Cable Shuttle Valves or Trolling Valve do you think there any point in increasing the size of the heat exchanger when the problem could be one of the problems that you have highlighted. Thanks for your help.

I have a Capital Hydraulic Gearbox, this box was recently completely rebuilt and ever since the rebuild it has a bad overheating issue, the rebuilders are suggesting a larger raw water heat exchanger that I am just about to install one but I was wondering if there was someone with any idea why this has started after the rebuild. It will run all day at 6knts but as soon as you step it up the heat come up with it.