Which is the lesser evil?

[Jeepguy]

On my old 185 Sport I would occasionally raise the trim up to 3/4 when in shallow water. I know this is hard on the bellows, so I never ran at more than idle speed.

On my new 220 Sundeck the trim switch requires an extra push to lift the trim above 1/2. At this point the Smartcraft gage reads "trailer". I am reluctant to run the outdrive at all in "trailer".

The water levels are low this year and the mouth of my channel is only 1.3ft!
If I only trim the engine to 1/2 I run my brand new stainless Bravo III props through all kinds of silt and sand and God knows what.

Which has the potential to cause the most harm? Running at 3/4 trim, or dragging my props?

 

[Lazy Daze]

I believe there was some kind of design change to the B3 whereby you can operate safely part way into the trailer range up to a specified RPM (somewhere around 1200-1500, IIRC). Either that, or Merc fine tuned their recommendations on high trim range vs RPM. Check me on this (probably in you manual), but I also believe the newer B3/Smartcraft setups will let you know if you exceed this new "safe" range.

FYI: it's not really about the bellows. It's about your gimbal bearing and the knuckles of the u-joint.

Edit: oh, I also wouldn't be nearly as worried about fine scratches on the props as I would be about suckin up sand and silt into the engine... Scoring/tearing the sea water pump housing/impeller and clogging the cooling passageways in the engine and the small hoses for the 1-point drain.

 

[Bt Doctur]

a 22 footer is almost drawing that much by itself ,park it and wait for some more water. add the lower leg and you looking at 3 feet minimum

 

[Jeepguy]

a 22 footer is almost drawing that much by itself ,park it and wait for some more water. add the lower leg and you looking at 3 feet minimum

I think when the boat reads 1.3 there's actually more there. It is weedy so maybe I'm reading some plant life. There is 27 Monterey, a 31 Trojan, and a 25 powerquest or something plus a few other bigger boats that go out that same way. All I need do is wait for their lower units to dredge it for me right?

 

[Tonka Boater]

I believe there was some kind of design change to the B3 whereby you can operate safely part way into the trailer range up to a specified RPM (somewhere around 1200-1500, IIRC). Either that, or Merc fine tuned their recommendations on high trim range vs RPM. Check me on this (probably in you manual), but I also believe the newer B3/Smartcraft setups will let you know if you exceed this new "safe" range.

FYI: it's not really about the bellows. It's about your gimbal bearing and the knuckles of the u-joint.

Edit: oh, I also wouldn't be nearly as worried about fine scratches on the props as I would be about suckin up sand and silt into the engine... Scoring/tearing the sea water pump housing/impeller and clogging the cooling passageways in the engine and the small hoses for the 1-point drain.

You are correct. The manual says you can safely operate in trailer mode up 1200 RPM....

Per the Mercury manual:

"The Power Trim SystemTrailering feature allows the operator to raise and lower the sterndrive unit for trailering,beaching, launching and low speed (below 1200 rpm engine speed), shallow wateroperation."

 

[Big Island Lifer]

Where is your depth gauge reading from? Is it hanging off of the back of the boat? How far under water is it? How far below the water line is your drive when in safe "trimmed mode"? It might not hurt to take a tape measure out so you know just how much room you have to work with.


Sent from my iPad using Tapatalk HD

 

[matthewmiller01]

Also, how is your depth gauge set up? Is it set to any offset? On mine (Smartcraft gauges), you can set the offset to many different levels (so that it can be reading depth from keel, depth from bottom of skeg, depth from waterline, anything). Verify your setup in the calibration menus on your gauge. It may be set differently than you think.

 

[surfinjoe]

On Lake St. Clair, you could be waiting a lifetime for the canals to 'rise'. LOL

The only hope is that the dredge!

a 22 footer is almost drawing that much by itself ,park it and wait for some more water. add the lower leg and you looking at 3 feet minimum

 

[surfinjoe]

The reading is a through-hull reading just in front of the engine. 1.3 feet is more like 3 feet of water!

Where is your depth gauge reading from? Is it hanging off of the back of the boat? How far under water is it? How far below the water line is your drive when in safe "trimmed mode"? It might not hurt to take a tape measure out so you know just how much room you have to work with.


Sent from my iPad using Tapatalk HD

 

[Jeepguy]

The reading is a through-hull reading just in front of the engine. 1.3 feet is more like 3 feet of water!

Pretty dead on guess!
I finally took out a tape measure. 1.3ft=38 inches