Towing - Leg up/down

gbader

Cadet
Joined
Dec 30, 2003
Messages
7
Hi all<br /><br />Sorry if this has been asked before (tried a quick search)<br /><br />Around town, I use the trailer locks when towing my boat (engine fully up). Seems logical to me and keeps the pressure off the trim/tilt rams.<br /><br />However, a local dealer has mentioned that this is not suitable for longer distances and there have been instances of these breaking. His suggestion was to lower the motor to a point where I can jam a piece of softwood between the engine and the transom housing and tie it down.<br /><br />I can see how this make sense (engine more vertical), less leverage (weight) on pivot point.<br /><br /> http://www.fishingworks.com/Users/UserFolders/gbader/PhotoImages/engine1.jpg <br /><br /> http://www.fishingworks.com/Users/UserFolders/gbader/PhotoImages/enginecloseup.jpg <br /><br />Just wonder what others do<br /><br />thanks<br /><br />greg
 

BillP

Captain
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Aug 10, 2002
Messages
3,290
Re: Towing - Leg up/down

I tow my mine down. I don't think it can be worse on the rig than running and bouncing off waves at full throttle.
 

Old Jarhead

Petty Officer 2nd Class
Joined
Sep 26, 2003
Messages
190
Re: Towing - Leg up/down

Hey Greg...<br /><br />I've been using the method suggested by your dealer for over 45 years now without a problem.<br /><br />I find, most times, the old rule KISS (Keep It Simple Stupid) works best. :cool:
 

Mettaree

Petty Officer 1st Class
Joined
May 17, 2003
Messages
292
Re: Towing - Leg up/down

Best use a transom saver - attached to rear of trailer, either to rear roller or to rear cross member. Need tilt/trim for proper usage to hold very tightly to transom saver then bungee cord around L/U to V-bracket on saver. For the bucks, its the best insurance against transom damage from any motor bounce. By putting on built-in locks the motor is a long, heavy lever putting pressure on the transom while going down the road.<br />Like a BIG monkey wrench clamped over the transom and putting loads of down pressure. Something has to give over time.<br /><br /> :)
 

gbader

Cadet
Joined
Dec 30, 2003
Messages
7
Re: Towing - Leg up/down

Thanks for all the replies<br /><br />200hp carries a fair weight so will need to "chock" it with something <br /><br />Bit of wood does the job but will check out the transom saver <br /><br />cheers<br /><br />greg
 

Oldsaltydog

Petty Officer 1st Class
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Jan 27, 2004
Messages
322
Re: Towing - Leg up/down

Just for the sake of discussion, let me mention a few things. It seems to me that the least amount of stress is placed on the transom when the weight of the motor is directed straight down. With the motor up and supported by the factory brace, the motor head and the shaft seem evenly balanced, at least on my boat, in other words, the weight pressure is going straight down. Whatever a person can do to maintain this position may be the best method. If the motor is elevated only partially, even if it's braced with a piece of lumber, which would certainly help, there could still be a BACKWARD twisting force exerted on the transom, which may possibly weaken the fiberglass over a long time. At least this is the way I see it. :)
 

quantumleap

Master Chief Petty Officer
Joined
Feb 16, 2004
Messages
813
Re: Towing - Leg up/down

A transom saver distributes some of that engine weight to the trailer instead of all of it on the transom. Also in reference to Bill P's theory, which would provide more cushion, hitting a length of board on the concrete or on the surface of the water? Water has more 'give'. Plus, as you are coming off a wave, your lower unit pierces the water surface first, displacing some of the weight of the outboard. When you hit a pothole in the road, the entire weight of the outboard is transfered to the mounting bracket and holes.
 

BillP

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Re: Towing - Leg up/down

More rambing thoughts...<br />I think damage is more fright that fact. Look at all the ob rigs that trailer...how many have broken transoms or broken motors from trailering? I never hear of it and never seen it. I've got a few miles (20k?)trailering outboards and never a hint of problems.<br /><br />Calculate the inertia of a motor hitting a pothole compared to thrust while jumping waves. My money goes on wave jumping being harder on the transom. <br /><br />Look at how much a boat moves on the trailer while riding. I personally don't want my motor being jerked opposite directions by a "transom saver" that mounts to the trailer. There are FEW trailers that don't flex while bumping down the road. If the trailer doesn't flex the hull does. The more I think about it the less I like the idea of a "transom saver".
 

MajBach

Chief Petty Officer
Joined
Jun 21, 2003
Messages
564
Re: Towing - Leg up/down

EBG: Your assumtions are wrong. Can't prove it here so if you really need to be convinced, talk to a mechanical engineer. Tell you what, here's an experiment that will duplicate the conditions on the back of a boat. Hold a chair at arms length above the floor. Easy? Now bring it slightly towards up and up at the same time - duplicating the pivoting action of a OB on a transom. Feel easier?<br /><br />Bill:<br />You bring up a good point, I too have never seen damage caused by not using a TS. Then again, I rarely see heavier motors trailered without them.<br />But i still have to disagree with you on this ( a first). When the boat is being trailered, only the boat is supported. Furthermore, what we're really talking about here is inertia and overcoming it. By size (i mean like density), a boat is much lighter than an OB. Resisting the forces of interia are much easier this way especially considering it's done over the entire length of the boat - or at least over the area the boat is resting on. But even this is irrelevent. For the most part, the boat moves with the trailer and is supported by such. But the OB is supported only in one small area and add to that, it is heavy for its size AND sits in such a way as to act like a lever, compounding the forces of intertia. To me, it's only common sense to use a transom saver. Since the boat moves with the trailer and a transom saver essentially ties the OB to the trailer, all three units now move as one.<br /><br />I also strongly disagree with you on the forces on the water being the same as on the road. The entire idea of a transom saver is to make the boat and motor move as one, i.e. same speed and direction. When you're coming off a wave, it's doing that already. Boat hits water, water stops boat. Outboard hits water, water stops outboard. Where's the twisting force on the transom?<br />Besdies, let's see you dive head first into a pot-hole.
 

oregonducker

Petty Officer 2nd Class
Joined
Feb 10, 2004
Messages
189
Re: Towing - Leg up/down

For what it's worth I tow in the up position because I don't like the ground clearance in the down position. If everything sat up higher I'd tow it in the down position. The motor is a 40 horse and wieghs only 170 pounds. The transom on my boat is braced in a way that probably makes it well above average in strength for similar boats.<br /><br />Here's a thought about the leverage on the transom others have mentioned. I'd bet the force of a hole shot (getting the boat on plane) is higher than hitting a pot hole on the road. Springs and tires absorb lots of shock on the trailer for one thing. The motor is attach to the transom so that whatever the cause of the leverage it will be applied to the same spot on the transom. In that case if the motor is down there should be less. But how much force is being applied to that point by the prop before the boat is on plane? I think it's a lot more than a bouncing trailer. Much more. Depending on horse power and boat weight of course.
 

MajBach

Chief Petty Officer
Joined
Jun 21, 2003
Messages
564
Re: Towing - Leg up/down

In that case if the motor is down there should be less.
This is simply not true. See force vectors, center of gravity, moment arm. <br /><br />
how much force is being applied to that point by the prop before the boat is on plane? I think it's a lot more than a bouncing trailer. Much more
I don't, but I have no way of backing that up. Gunning the OB during a hole shot certainly mimics the same forces it would experience on the road. The only difference is that the boat can actually move in response to this force. <br />An excellent point nonetheless which perhaps cuts my theory all to s***.
 

rickdb1boat

Supreme Mariner
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Jan 23, 2002
Messages
11,195
Re: Towing - Leg up/down

Next time your going down the highway and see a boat being towed without a transom saver, watch the motor bounce up and down and then keep that in mind. Doesn't take much rough road or a big motor. Seen it dozens of times on the way to the lake over the years. The ones with the saver ride nice and smooth. I have never seen a true bass boat with a large engine not being towed without a saver, so that must say something...
 

BillP

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Aug 10, 2002
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Re: Towing - Leg up/down

I have never seen a true bass boat with a large engine not being towed without a saver, so that must say something
Come to Florida and look at the 1000s of trailer boats that don't use transom savers. Few use them here. The many big rigs with multi 250hp engines on trailers here make bass boats look pale in comparison.<br /><br />There are formulas to calculate all the stresses. One of you whizz engineers should be able to do it for us. A boat hits a 6" deep pothole at 50 mph. The motor is on a 12" arm and the powerhead weighs 175lbs... The same motor puts out ***lbs thrust on a 75% longer arm with varying loads at angles up to 90 degress and accelleration at different rates and directions (fwd to reverse). Which works the transom harder?
 

quantumleap

Master Chief Petty Officer
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Feb 16, 2004
Messages
813
Re: Towing - Leg up/down

Look at how much a boat moves on the trailer while riding.
If your boat is moving around on the trailer, then either you're not using tie-downs, or your trailer is shot. Try not to drive too fast with that set-up! Bill, if you really can not understand how a transom saver puts less stress on the transom of the boat, then I suppose it isn't worth anymore of my time trying to explain it to you.
 

Chinewalker

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Aug 19, 2001
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Re: Towing - Leg up/down

The transom savers may very well reduce towing stresses on a boat, but I don't beleive they're necessary. Bottom line is that if your boat is otherwise healthy (not rotted out, properly supported on the trailer, etc.) then towing with the motor up or down really shouldn't make a difference as far as the boat goes. I can't say that I've ever seen an outboard laying by the side of the highway with half a transom attached...<br />- Scott
 

quantumleap

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Feb 16, 2004
Messages
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Re: Towing - Leg up/down

I don't think anyone is suggesting that the transom is going to bust off during transport S.A. However, I'm sure you've heard of 'gelcoat stress cracks' and 'plywood delamination'. Any steps you can take to protect the structural integrity of a boats transom and hull are worthwhile.
The transom savers may very well reduce towing stresses on a boat, but I don't beleive they're necessary
This is like saying 'Dock fenders may very well reduce hull damage but I don't believe they're necessary.' Why do you use them, to protect your hull. Same with transom savers, to protect your transom. I guess some people just have a little more concern for the longevity and appearance of their boat than others.
 

Chris1956

Supreme Mariner
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Mar 25, 2004
Messages
28,141
Re: Towing - Leg up/down

I trailered my boat for many miles in its lifetime. I normally tilt it up about 25% to give extra ground clearance yet keep some weight holding it down. I have had zero problems with the trim and tilt system, and the motor does not bounce. I expect that the pounding the motor takes on the water (50+MPH) and waves is much more severe than any road bump. I also think the transom also had much much more stress on it under power in the water.
 

Chinewalker

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Re: Towing - Leg up/down

Well actually, it's NOT like saying the same thing and substituting "fenders" in place of "transom savers". If you live where I live, dock fenders ARE necessary. I can SHOW you damage incurred on a boat without fenders. I've never seen a stress crack develop from towing. I HAVE seen stress cracks develop from actual on-the-water use. Simply put, the stresses incurred while underway are FAR greater than those anyone is likely to incur while towing. ... <br />- Scott
 

rickdb1boat

Supreme Mariner
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Jan 23, 2002
Messages
11,195
Re: Towing - Leg up/down

OK, Bill and whoever, I give! You guys can tow with the motors hangin' off the back and tilted down with no support, but I'm gonna support it and ride with it up. If you really don't think it puts stress on the transom, then that's fine....
 
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