Yanmar Pleasure Boat Marine Engine Help

SEA TRIAL

A seatrial is the final step where all that agro you went through to build your boat slides into obscurity. This is the point where everyone's ideas float, or don't float, and where everyone you know, who knows you, who thinks they know you and who wants to know you, turn up for free beer.
Let me give you a couple of tips:

• Don't do the sea trial on launching day! (That's the free beer day.)
• It is still the boatbuilder's boat until the seatrial is finalized. He / she is the person responsible for giving you what you paid for.

Now that's over, we can get on with it.

• How should the trial be done? Let's assume the boat has been in the water overnight, the engine(s) have been run and the electronics work almost as advertised. You have an anchor with a warp that is tied to the right bits at both ends.
  ( Check it, 9 out of 10 times the warp wont be tied to the anchor let alone the boat! )
• Check the chart and see where you are going to go, if you have a power boat you will need 30 minutes at full power so you don't want to run out of sea room! Many harbours have a 'measured mile' ( 1 nautical mile) where you can check the boat speed. The boatbuilder may already have this local knowledge. If there is no 'measured mile' you can measure the distance between two points on the chart and take the time between them.
• 1 Nm in 2 minutes = 30knots, in 3min = 20knots, and variations thereof, etc.
• OK, homework done, let's check for leaks, water, fuel and exhaust gas! Ask all the dumb questions now because the 'experts' aren't going to be there soon and you want to know what you're looking for when you open the engine room to do your preflight. Everything secure? Engine room is clean? (You are now about to use your XXX hp vacuum cleaner(s) and you don't want all that boat building rubbish going into the filters.) You also don't want that nice, very expensive furniture flying around the boat in a rough seaway because they aren't really ready yet. If it isn't ready, ask them when it will be and go away, come back when they said it would be OK.
• The boat should be full of fuel, water and other ballast and have all the necessary tradesmen on board, leave your mates at home! If this is a final engine acceptance seatrial the boat must be fully loaded to it's maximum operating weight.
• OK, everyone is ready! Start the engine(s), check the boat moves in the right direction when you operate the controls, if all is well untie the mooring lines and get moving, don't idle at the dock for longer than you need to check that the engine is running and you can untie. Prolonged idling of diesel engines is not good for them. (this is not a truck!)
• Maintain idle to 1500rpm until the engine temperature has stabilized. At this point, if you're legal, you can push the 'go' lever until you have 50 - 60% rpm.
• A planning hull may need lots of power to get on the plane, use it and then slow the engine down again. Before doing any speed tests, with turbocharged engines, increase the rpm by 200rpm every 5 minutes or so until you have reached full power. The engine tradesman should be measuring the rpm with a * hand held tacho, he will tell you when he is ready and you can increase the rpm.
• On non turbo engines you can move a bit faster to full power, take about 15 minutes.
• If the engine can't reach its correct maximum rpm then slow down, return to the dock if necessary and have it fixed before trying again.
• With turbocharged engines carry out a 30 minute full power run after the maximum rpm has been checked and is OK. Keep an eye on the engine temperature, turbocharged engines can rise in temperature, but not into the red section of the gauge during this run. If it does, either the gauge is faulty, there isnt enough cooling water or there is something wrong with the engine.
• The oil pressure may drop as the engine gets hot, that's OK.
• Check the exhaust for smoke.


Running in
• Finally, when the engine rpm is correct, the seatrial is over and you've got rid of the hanger-ons, run-in the engine. (Yes, I know, we just gave it a good workout!) For the next 5 hours running don't operate the engine at more than 85% rpm or less than 2000rpm and every 20 minutes change the rpm up or down by 200rpm. When the 5 hours are up you can do what you like.
• MAXIMUM LOADED RPM

* he may use an optical tacho or a tacho that counts the pulses on the injector pipes or other similar devices that can be read remotely, he no longer has to deal with the rotating machinery in a heaving seaway. Just be sure he is not using the boat tacho to set up your turbocharged engine. Non turbocharged engines are not so critical.
HAPPY BOATING SKIPPER

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