Operating Range for Trim at Low Speed and Shallow Water

[Mooring10]

I just upgraded from a 2003 Crownline 192 BR with a 5.0 Carb Alpha drive to a 2017 Monterey 218 SS with a 4.5 MPI Alpha drive. In my 2003, it was clear the operating range for the trim went up and down with the toggle on the throttle handle. If I wanted to tilt to trailer up, I pressed the upper toggle harder/further and the outdrive raised to the trailering position. My new to me 2017 has the same type of switch on the throttle, and a trailer icon on the top of the toggle. However, the outdrive moves from full down to full up (trailer) and there is not stopping at the top of the trim range. Has this changed--is there no operating range for the trim anymore? I don't know how high to raise the outdrive to operate in shallow water without harming the u-joints/gimble. With my 2003, the operating range of the trim was very clear. All I have now seems to be the instrument gauge. Is there still a top limit for trim and the further tilt to trailer?

 

[achris]

Hello Mooring10 and :welcome: aboard

...However, the outdrive moves from full down to full up (trailer) and there is not stopping at the top of the trim range. Has this changed--is there no operating range for the trim anymore?...

No, this has not changed. It sounds like the PO may have had a problem with the trim limit switch, and has 'jumped it out'. It's actually really easy to do. If you want to reinstate it, and the switch is actually working, then it's a simple matter of finding the wires that come from the switch and reconnecting them to the trim pump harness. If you want to do this, I can provide diagrams and help you along the way. How are your electrical skills?

As for 'doing damage to Unis', I have been in situations where I NEEDED the drive all the way up to cross a sandbar (should have got out and pushed the boat across!). As long as it's just at idle and you're not putting big steering changes in, for a bar crossing or similar, it's fine. The unis see more movement in a full port-starboard steering swing than a full up trim. The problem is when you try to start the engine with the drive full up, the sudden acceleration of the engine is what does the damage.

Chris.........

 

[Mooring10]

Thanks for the reply. I bought the boat from the dealer, but now I'm about four hours away. If I were able to convince him to "fix this," is it ok to run it this way for the season?

I would like to try to "un-jump" it, but to answer your question, no, I'm not very electrical or mechanical--so perhaps I need to leave this to those more informed?

 

[achris]

I haven't had a trim limit switch operational in my boat since I bought it, 1986... You're fine to keep using it...

If you want to know roughly where the 'limit' would be, have someone trim UP while you measure the length of the ram... And when you get to the ram being 520mm extended (mounting point to mounting point), mark your gauge. That's your trim range...

Chris...........

 

[Mooring10]

Thank you; will do.

 

[Mooring10]

Not that we are building watches here, but 520 mm converts to 20.4724 or 20-1/2, not 20-3/4 inches as shown in the diagram. Wonder why the discrepancy?

 

[achris]

Not that we are building watches here, but 520 mm converts to 20.4724 or 20-1/2, not 20-3/4 inches as shown in the diagram. Wonder why the discrepancy?

Next question?

 

[harringtondav]

Hello Mooring10 and :welcome: aboard
As for 'doing damage to Unis', I have been in situations where I NEEDED the drive all the way up to cross a sandbar (should have got out and pushed the boat across!). As long as it's just at idle and you're not putting big steering changes in, for a bar crossing or similar, it's fine. The unis see more movement in a full port-starboard steering swing than a full up trim. The problem is when you try to start the engine with the drive full up, the sudden acceleration of the engine is what does the damage.
.

Hear-hear Chris. This is my SOP at a sand beach. I trailer up just enough before the prop starts splashing and I paddle in to the sand. I've never been able to operate my boat in full up operational trim...regardless of the speed. Prop break loose/cavitation happens well before full trim up.

My son is a decent boat pilot, but every year after he takes the boat/river place for his Labor (Labour) Day weekend the skeg is polished and/or a prop blade is dinged. He's never connected with my instructions with the "trailer up" thing when approaching a sand beach. We'll do a couple touch and goes before his next mate's weekend.