Power trim and tilt vs underwater objects?

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ktoelke54

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I’m considering a new outboard purchase in the 25 hp range (maybe the new Yamaha) and was wondering about power trim and tilt and river running. I do a lot of my boating on a river where shallow water and rocks are the norm. I have been using 2 strokes, a 15 and a 25, which tilt ok by hand. I use a prop protector and run with the motor unlatched. When I do bump a rock the motor just kicks up, no damage to the prop, skeg or lower unit. Mostly I’m going slow when this happens and it’s not that traumatic. But occasionally I’ll bump one at full tilt and as much of a shock as it is I have not, as of yet, incurred and damage.

So if to save my old back, I bought a new 25 hp with power trim and tilt, do you think it would work for me under these conditions?
 
There is a bypass circuit/path in hydraulic trim systems for that very reason, but we’d need Pappy to chime in and advise if they are as responsive to strikes as your other motors were. My gut tells me ‘no’, but that’s a guesstimate.

Now I did hit a log w/ a V6 OB once whilst up cruising on plane and that motor sure bounced up (and suffered no damage, if you can believe it!), but either way ... there’s still a lot of metal in motion and I’d like to see what an expert thought.

TurboTodd here is really sharp on motors too, so maybe he’ll see this post too.
 
I live in/run in rocky/stumpy areas all my life. I use my boat for hunting out of as much as fishing and do a lot of messing around at night coon hunting. This requires a bunch of tooling around in extremely shallow water. Your trim/tilt will not move. It is either going to tear the transom or lower unit up in an extreme strike.

That being said I have never torn a LU or transom out, but I have been the owner of several new props. I made this contraption and it solved my issues. It is very similar to the Macs River Runner with a few mods.
propguard.jpg
 
nccatfisher said:
I live in/run in rocky/stumpy areas all my life. I use my boat for hunting out of as much as fishing and do a lot of messing around at night coon hunting. This requires a bunch of tooling around in extremely shallow water. Your trim/tilt will not move. It is either going to tear the transom or lower unit up in an extreme strike.

That being said I have never torn a LU or transom out, but I have been the owner of several new props. I made this contraption and it solved my issues. It is very similar to the Macs River Runner with a few mods.

I use a Mac’s River Runner, that is what I thought you had till I took a closer look. Yours looks even more heavy-duty.


Sent from my iPad using Tapatalk
 
What you want is a breakaway plate which is a jackplate that pivots at the top when you hit an obstacle.A proper breakaway plate should have a safety strap or some type mechanism limiting its travel.I have hit a log at speed without power-trim and the lower unit swung up nearly vertical breaking the transom bracket.It is not inconceivable that the spinning propeller could end up inside the boat.I now have a length of heavy nylon webbing around the leg secured to the transom.Not sure if the release valve in a power trim would prevent "rapid deceleration" if you hit something big in a light boat.m.w.
 
ktoelke54 said:
nccatfisher said:
I live in/run in rocky/stumpy areas all my life. I use my boat for hunting out of as much as fishing and do a lot of messing around at night coon hunting. This requires a bunch of tooling around in extremely shallow water. Your trim/tilt will not move. It is either going to tear the transom or lower unit up in an extreme strike.

That being said I have never torn a LU or transom out, but I have been the owner of several new props. I made this contraption and it solved my issues. It is very similar to the Macs River Runner with a few mods.
propguard.jpg

I use a Mac’s River Runner, that is what I thought you had till I took a closer look. Yours looks even more heavy-duty.


Sent from my iPad using Tapatalk
It is heavier but has larger holes in the front to allow less resistance. It was a trial and error type of thing. It has served me well on several motors over the years.
 
If the piston in the trim ram is equipped with impact valving the engine will indeed swing up and over an object. Some systems will not return to the run position afterward.
Having not looked at the new system I can only offer this.....
Manufacturers, while designing a new outboard, normally do impact testing until destruction. To make a long story short the parts of the engine that allow tilting, trimming, and clamping to a transom are designed to do their job and also break in a pre-determined order for safety.
Of course the testing is done in controlled circumstances and your results will most certainly vary in the real world. WOT operation and a serious hit? All bets are usually off !
This brought up some fun memories!
I have done factory destructive testing on both outboard and stern drive product. Testing was done on-water at precise trim angles and speeds that were progressively faster and more destructive. We did the testing while driving inside a protective cage built into the floor of the boat. Drive units were always tied to a rope and flotation marker which exited with the drive when it finally started breaking completely off. Outboards were also attached to a rope and marker but were usually held by the steering cable or cables after they broke off. Outboards at high speeds did come in the boat and back out on more than one occasion vs. never for a stern drive. No matter how good you think you are at running the boats for this testing the boat will almost always hook to the left when the drive or outboard breaks off and you will always try and steer it straight.......with no engine or drive to do it with! :roll:
Back in my test driving days I did have two V6 200/235hp outboards break off (two separate occasions) and come in the boat with me with no protective cage. One left prop marks as it slammed down that were less than a foot away from the front of my seat. Both engines exited as fast as they came in and were found at the end of the steering cables under the boats.
 
There are products like this. They are jack plates designed to swing up. Would provide the break away you are looking for plus gain set back vertical adjustment so you can raise the lower unit up as much as possible.

https://www.vancemfg.com/product-p/jpl9638-gen3.htm

JPL9638-GEN3-2T.jpg
 
Pappy said:
No matter how good you think you are at running the boats for this testing the boat will almost always hook to the left when the drive or outboard breaks off and you will always try and steer it straight.......with no engine or drive to do it with! :roll:
Grab that wheel ... and turn it harder!

Pappy said:
Back in my test driving days I did have two V6 200/235hp outboards break off (two separate occasions) and come in the boat with me with no protective cage. One left prop marks as it slammed down that were less than a foot away from the front of my seat.
O M G ... glad you’re still here to talk about it ...
 
ktoelke54 said:
wmk0002 said:
There are products like this. They are jack plates designed to swing up. Would provide the break away you are looking for plus gain set back vertical adjustment so you can raise the lower unit up as much as possible.

https://www.vancemfg.com/product-p/jpl9638-gen3.htm

JPL9638-GEN3-2T.jpg

Thanks, that looks like it would work.


Sent from my iPhone using Tapatalk

Good luck. Don't personally have any experience with that product but recently bought their mini jacker and it is a very nicely made jack plate. Great quality and considerably cheaper than others. Bet you can find some more info on the duck hunting forums out there.
 
The yamaha will kick up but it takes a pretty good lick. BTDT.

In order to get power tilt on the Yamaha, you have to order/buy the motor as a remote steer, and have them install the tiller kit-which adds expense to the motor. I hate how Yamaha does that with the smaller motors. I may be in the market for a power tilt 15 or 20 but I gotta look into it more. It'd be for my dad's boat that he just bought.

The newest version of the 25 tilts as easy as the old 2 stroke 25. I've got a 2018 25 and had a 2007 25 (2 stroke)-and there isn't much difference in manual tilt effort.

You can run a kickup plate such as shown above but some of them don't come with a chain, so you'll have to add one. That or a cable of some sort. The good thing about the kickup is that it moves the motor back about 5", which allows you to raise the motor, which gives you some more clearance for running skinny. I JUST got in from running a skinny river; didn't hit anything, caught plenty. I have my motor raised on the transom about an inch and a half with a wood spacer. Every little bit helps on certain waterways. It was so bad this morning that I was able to run on plane the entire 5.1 miles to the hole, but going back....water dropped about 2', had to get out & pull the boat over a gravel bar manually. Wasn't a big deal; just enough to float it over without me in the boat, about 4-5" deep. Sure was cold though.
 

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