I assume you are talking about the two big pokey out things at the bottom of your clamp bracket?
In days of yore, all Power trim looked like that. (after the initial version that consisted of big external twin rams with a cat's cradle of hydraulic hoses). Now smaller engines use a single cyl, but larger machines still need the extra "grunt" given by the three ram systems.
Basic idea goes like this:
When running, the swivel bracket sits against those two rams. They have a big area piston behind them (x2) so the tiddly little hydraulic pump & valves can handle the pressure the engine excerts on them when at full chat. (Pressure = Force/Area - rearrange it to give Force = Pressure x area)
When the engine is trimmed out beyound the point of contact, the middle ram takes over. This has enough grunt to lift the engine, but not enough to handle the force created by the prop thrust. (it is always pressurised, but is incapable of holding the engine against prop thrust, so drops to the rams when the prop is working)
If you trim out slowly on land, you'll also notice the "not touch" point is when the swivel bracket is still (just) in between the clamps. Much further up & you run the risk of snapping it clean off, as it's only held in place by the tilt tube. Hence the design!
Single rams have a bypass port part way up connected to a low pressure relief valve, so that it instanly has a way lower hold pressure and drops back between the clamps when the throttle is opened.
If you are truimmed "all the way up" it may be off the rams when you start, but it won't take much, especially at 140 HP on a 6m+ boat to get it back down again!
Hope that both made sense and was what you were asking about!