There is a big engine over here. On a heavy foundation. Massive steel. I don’t know how much it weighs. My guess is that this has got something to do with a water coolant pump. This must be the case. Yellow hoses lead to the cooler over here. It seems to be running in step with the engines. It’s probably a shared cooler for several motors. This must surely be the case. It’s connected here. Let’s take a closer look at it. See If we can get some more information. My guess is that it’s a Hundested Motor (Danish Engine) it says HM. Lubrication Display here. A big flywheel. Most likely a ships engine. Let’s see if we can get round, without getting hurt. Let’s see if we can get some information about it. Sorry for interrupting, but what kind of engine is this? It’s a Hundested Motor. How many HP and key data? It’s got a bore of 330 millimeters (one foot) and has an iron piston. It’s got 60 HP. What year is it from? It’s from 1958. And it’s been used in a fishing vessel, or what? It’s been used in a fishing vessel, that was scrapped down here at Grenaa Port, at Peter Niemann’s. This one is actually identical, but with an aluminum piston. It’s on the way back to the, Museum Ship, Hansa, in Skagen. I presume they will be coming to look at it sometime today, and will take it with them sometime this week. Couldn’t you explain what the advantage is of an aluminum piston, for those who don’t know? Aluminum is lighter, making it possible to run at faster RPM’s. Faster RPM’s result in a bigger momentum, giving 20 HP extra. So it has got 80 HP, instead of the 60 HP it was born with – with an iron piston. You get 20 HP on top. Simply by exchanging an iron piston with one made of aluminum? When did one start to use this, trick, on might call it – to change the pistons to aluminum. Do you know? One started in the late sixties, and after significant problems in the start, it began to work. What were those problems – that the pistons melted, or what happened? Yes, both that they melted. It was also a question of finding the right alloy. Another thing was that they expanded fast, when heated, giving problems with to tight tolerances between piston and cylinder. When starting the tolerance is big and it rattles somewhat. If one just chooses to start the engine, and sail of, one gets a problem with the piston expanding faster, than the cylinder, with the piston seizing in the cylinder. Was this solved with the right alloy, or what? No, it was solved with a combination of better alloys, suitable tolerances, and by teaching people how to operate these engines. What does the last thing imply? That you have to warm up the engine before sailing. Start it, and let it idle for 15 – 20 minutes before sailing. Like with an old fashioned car? Yes, yes. They are identical these two engines, but one of them has got 80 HP, because it’s got an aluminum piston, and the other has got 60 HP, with an iron piston? Exactly. How much do such pistons weigh? This will be an estimate. I would set the aluminum piston to 50 – 60 kilos. The iron piston probably weighs 100 kilos. Thanks. The basic information: what is the engine principle her. A semidiesel, probably, but what does that cover? It’s a two stroke, or what? Yes it’s a two stroke, and not like a conventional diesel running at high pressure, but semi – with a lower compression ratio. When idling, it works like an old fashioned glow head engine, where it gets the fuel injection very early, with prior gasifying, but when running at full throttle, it ignites like a diesel with no prior gasifying. In Norway and other places its called a semidiesel, but we call it a glow head engine. Starting, how does one do that? With compressed air. Doesn’t it need to be preheated? Yes, first one used start cartridges, but after that one changed to electrical preheating, just like on diesel cars, that are preheated first. Start cartridges, what is that, what do they consist of? It’s a gunpowder mix with sulphur, that burns slowly, and makes a big flame. You screw it down into the top, and then start with compressed air. Then the injected fuel ignites on the flame inside, and when its churned three times, it’s so hot in the sot, that it can ignite by itself. You are saying that the sulphur that burns slowly works over 3 piston up-strokes. Yes, and then it is sucked out through the exhaust. When did one drop this, in favor of electrically preheated starting? Also in the late sixties, where more and more fishing boats got electricity onboard. The boats that where a bit old fashioned, still didn’t have electricity in the late sixties. Okay, thanks a lot. This is a Grenaa Diesel, that makes a bit of a noise. We have just heard an engine expert from Hundested Motor explain about these engines. Two identical motors. One with a cast iron piston here, that therefore rocks more, also when idling. As opposed to a similar one with a lighter aluminum piston, that simply does not generate as much vibration, and unwanted rocking. because the mass of the piston going up and down is smaller.