Drive angle during trailer power up

jmarty10

Chief Petty Officer
Joined
Aug 6, 2007
Messages
560
Hello all - I have a 2008 larson 180 sport I/O 190 hp. Am loving the boat and having a great time with it and family. When reading the merccruiser engine manual I noticed it saying that it is very dangerous for the drive unit if you have your drive all the way up in trailer position and you go more than 1200 rpm. When leaving the water I power up onto my trailer as I have in and out service with a marina. The areas around the launch are shallow so I keep the drive pretty high (3/4 high) as not to hit anything at bottom. I power up with prop still in water and go about 2000 to 2200 rpm until boats all the way up on trailer. Is keeping the drive that high and powering up at that RPM range for a short period of time going to hurt drive? Thanks
 

gcboat

Lieutenant Commander
Joined
May 29, 2007
Messages
1,822
Re: Drive angle during trailer power up

It will put an undue strain on your u-joints but I'm not too certain that it will cause failure. If it were me I'd be tempted to cut off the motor, tilt the drive unit up and winch it onto the trailer.
Here in the sunny south it is frowned upon highly to power onto your trailer.
Degrades the underlayment of the ramp ( eventually ) and just really makes a mess. I don't believe there's a written law about it - just common sense I suppose.:confused:
 

Bob_VT

Moderator & Unofficial iBoats Historian
Staff member
Joined
May 19, 2001
Messages
26,064
Re: Drive angle during trailer power up

Power loading is not a good practice in my neck of the lake. It blows the base away from the ramps and creates an unsafe drop-off.

I would load using a strap/cable winch so I can avoid doing damage to the drive too.
 

Splat

Lieutenant
Joined
Jul 20, 2008
Messages
1,366
Re: Drive angle during trailer power up

Do it right and use the winch.
Bill
 

skargo

Banned
Joined
Sep 14, 2008
Messages
4,640
Re: Drive angle during trailer power up

I'm a newb this year to launching and retrieving, and I pull it up with my dock lines, then I winch it in. I do this because of what I have read in my research, and from the signs I have seen at quite a few of the ramps I have visited. I might not look as cool as the guy powering it on, but at least I'm giving my fatass some exercise. :D
 

ShaneCarroll

Chief Petty Officer
Joined
Feb 10, 2009
Messages
639
Re: Drive angle during trailer power up

skargo - could not agree with you more. Heck, I volunteer to winch other people's boats up to drop a few unwanted lbs. Guess these Corona Lights ain't doing the trick either.

In regards to destroying the boat ramps, I had an experience with that, quite unpleasant, I might add. I was guiding a buddy of mine on his trailer, as I was going to winch it up, and pull his truck out of the ramp, so I walked out towards the end of the trailer while it was submerged. He drives up to the edge of the trailer, and I winch the rest of the way up. Well, dumb me doesn't notice the trailer tires floating, so I continue walking, and next thing I know, SPLASH!! I went into about 10 feet of water right off the end of the ramp. I couldn't get mad at anyone but myself, and hey, at least the 5000 people (or so it seemed) on the dock got a good laugh.

To be quite honest, I never saw why you would have to power the boat onto the trailer. I will do a quick idle, and that gets my boat 3/4 of the way up, and I winch it the rest of the way up.
 

ziggy

Admiral
Joined
Jun 30, 2004
Messages
7,473
Re: Drive angle during trailer power up

i don't do what your doing to your drive. it can't be good for it. think about the ujoint tool in your toolbox. how when you have to use it, the more exstream angle it is, the harder it becomes for the ujoint to flip around to the other way as the bolt is driven. now do that at 2k. not me.

i'm with skargo too. lines and walk it down the dock to being on my trailer and winch it up. it's just too easy...

sc. i've been unhappy with the wash out from the ramp too on the river. myself, my tires fell off the edge of the ramp and i got the leaf springs traped against the edge of the ramp. i could not get free. i had to purposely get in the hole to free myself. i was very lucky i had three people that day (gf to drive and me and my boy on ea. side of the trailer to lift) and even luckier me or my boy didn't loose a finger or worse lifting the trailer to get the shackles over the ramp edge... it was a drag for sure..
 

strokeoluck

Petty Officer 1st Class
Joined
Jan 4, 2009
Messages
353
Re: Drive angle during trailer power up

We've only had the boat on the water a half dozen times or so, but I agree that winching up is the way to go for us.

But I still don't quite understand the whole issue w/leaving the lower unit somewhat raised while motoring around. We did it recently when in some shallow areas (very low speeds and rpm). Can someone provide a link to a good diagram of a "U-bolt"? I have no idea what it is/does, or why this practice is bad for it. Thanks!
 

180shabah

Rear Admiral
Joined
Mar 26, 2005
Messages
4,995
Re: Drive angle during trailer power up

Want to see a u-joint - go look at either end of the drive shaft under your truck.

They allow flex, but only a few degrees, beyond that and they bind up and wear out quickly. When they let go you are left with one end of that rotating shaft flailing wildly.
 

sea wolf

Lieutenant Junior Grade
Joined
Apr 3, 2002
Messages
1,219
Re: Drive angle during trailer power up

Winch it on. It's safer. Just be patient & let the wife take a break when she gets tired.
 

koberlee

Seaman
Joined
May 10, 2007
Messages
52
Re: Drive angle during trailer power up

We've only had the boat on the water a half dozen times or so, but I agree that winching up is the way to go for us.

But I still don't quite understand the whole issue w/leaving the lower unit somewhat raised while motoring around. We did it recently when in some shallow areas (very low speeds and rpm). Can someone provide a link to a good diagram of a "U-bolt"? I have no idea what it is/does, or why this practice is bad for it. Thanks!

The angle of the outdrive to motor puts the u-joints on your drive shaft under more stress and also when you raise your outdrive past around a quarter way up it comes out of the two supports on either side. Take a look at your outdrive when down and the bottom of it is inside the supports when up it comes out of these.
 

koberlee

Seaman
Joined
May 10, 2007
Messages
52
Re: Drive angle during trailer power up

Also it is find to run it up and go slow, just like it says in the manual, do not exceed 1,000 rpm when you are trimmed up.
 

Susquehanna Squid

Petty Officer 2nd Class
Joined
May 21, 2009
Messages
146
Re: Drive angle during trailer power up

I agree, winch it on. I like to get a good bit if speed then kill the motor and while drifting in I raise the motor and guide it on. Our ramps around these parts can be pretty steep and I am still able to load this way. And, by the way Shane, I too have walked the plank and lost.
 

Gary H NC

Fleet Admiral
Joined
Dec 1, 2005
Messages
8,972
Re: Drive angle during trailer power up

I think i am the only one who winches the boat on at my local ramp.
I get plenty of strange looks for doing it too.
The way my trailer is driving it on is about a 50% chance it will not center on the keel rollers.
I can still load faster than most people power loading.I watch them take 3 or 4 tries to hit the trailer straight.
 

Schmoe

Petty Officer 2nd Class
Joined
Feb 10, 2004
Messages
117
Re: Drive angle during trailer power up

Don't go past the highest trim setting. Anything above that will eat the U joints up. If you put it up too high, you'll start hearing a knocking sound and that is not good. Agree with others, winch it up. Plus, that way you know you have the boat lined up right as you pull it up on the trailer.
 

jmarty10

Chief Petty Officer
Joined
Aug 6, 2007
Messages
560
Re: Drive angle during trailer power up

Thanks for all the replies. I typically get the boat about half up on trailer and then give it throttle with drive up but still in water until it hits front roller. Were talking about 3-5 seconds at most at about 1500 to 2000 rpm. I think going forward I am going to keep the drive down lower. I dont think prop and skeg are going to hit.
 

rp23g7

Petty Officer 2nd Class
Joined
Jul 17, 2007
Messages
113
Re: Drive angle during trailer power up

I usually crank it on also, the boat ramp we go to is so shallow anyway that i have to get all 4 wheels wet on the Explorer before the boat will even come off the trailer. I figure if you power it on, you have a set of really large cajones, or enough money to replace the rear window of your vehicle.
 

ShaneCarroll

Chief Petty Officer
Joined
Feb 10, 2009
Messages
639
Re: Drive angle during trailer power up

Your prop and skeg could very easily hit the end of the ramp. That would not be good for either. You should be able to do as some people suggested on here, just idle up to trailer, and if your trailer is in far enough, you should never have to go above idle to get 3/4 the way up. From there, just winch it. Once you walk off the end of the ramp, you will see why so many of us gripe about "flooring it" to put it on the trailer. Either that, or when you rip your axle off the trailer, I have seen that numerous times. They just replaced one boat launch down here (well, by just I mean about 4 years ago) due to multiple axles getting ripped off. Now THAT will ruin your perfect boating day.
 

abj87

Petty Officer 1st Class
Joined
Aug 4, 2008
Messages
354
Re: Drive angle during trailer power up

POWER LOADING RUINS THE RAMPS. My local ramp has HUGE hole from people like you!!!!
 

BumbleBeeTuna

Seaman
Joined
May 5, 2009
Messages
66
Re: Drive angle during trailer power up

Although I have never done it, I have yet to see a sign posted to discourage power loading.

I would think there would be signs all over the place.

This weekend I saw someone slam on their brakes to launch the boat off the trailer, only to land on the concrete. The driver sat in the truck with his face in his hands for about 10 minutes while everyone stood in disbelief.
 
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