Trailering with motor tilted down or up?

[jtexas]

Re: Trailering with motor tilted down or up?

Originally posted by BillP:<br /> Torsion, shock load theory and logic is one thing but is really a guess that just sounds right. <br /><br />Look at the 10s of 1000s of trailer boats without transom savers and see how many broken transoms or motors you find. Virtually ...

I agree it's theory and guesswork since I haven't seen any definitive science on it, but...<br /><br />While it's true that I've never seen a broken transom at the lake, or on a trailer being towed to the lake, junkyards and classified ads are chock full of boats with bad transoms.<br /><br />It's a very rare boat on a trailer without a transomsaver in my neck of the woods, and we do have boatloads of boats.<br /><br />One bit more theory: with every flex, the transom gets a tiny bit weaker...with every flex prevented, I add a tiny bit of useful life to the boat. If I dropped the t/s in the lake or something & didn't have it, I'd still drive home. It's all just opinion far as I know.

 

[Silvertip]

Re: Trailering with motor tilted down or up?

As I indicated earlier there are two types of forces involved depending on whether or not the motor is tilted up or left vertical. The best scenario is to leave the motor vertical. The transom can handle those forces since it is supported by the trailer bunks and/or rollers. But on most boats, the engine cannot be left down because of clearance issues. With the engine tilted up, you now have at least a three foot long lever that when standing still, the forces are trying to twist the tranom out off the boat. There is probably in the vicinity of 80 pounds measured at the nose cone on a mid-HP engine and more on higher HP engines. Hit a rough railroad crossing, bridge approach, pothole or section of rough road and that force can be easily magnified four, five or six times. You can do the math from there. As a test, tilt the motor up and simply push up and down on the prop while watching the transom. It very likely moves. Now magnify that by a factor of five or six.

 

[bossee]

Re: Trailering with motor tilted down or up?

boatster,<br /><br />m-ywedge will works just fine in my opinion. <br /><br /> Link <br /><br />I have used it two seasons now without any trouble with my Yamaha F115.<br /><br /><br />/Bo

 

[BillP]

Re: Trailering with motor tilted down or up?

Take a 200hp engine, run it on a standard 20' production boat offshore in 4' swells at 40mph. The boat will be airborne every 8 seconds or less. The ride will be teeth and bone jaring. Everytime the boat hits the water it buckles your knees and it is difficult to hold on...The 300lb motor hits the water with approx 1000lbs thrust at a 3' arm. Most production boats will do this as long as you can handle it without breaking a transom. They break bottoms instead. This far overshadows anything that happens when trailering. Trailering torsions and shock loads are feeble in comparison. That's why you never see broken transoms on boats from trailering without transom savers. Rotten transoms are what you see broken out there.

 

[TOHATSU GURU]

Re: Trailering with motor tilted down or up?

BillP is correct. It is a fallacy that any transom saver is necessary under most trailering conditions. Outboard manufacturer's expressly warn against using their built in tilt locking devices for trailering because of possible warranty liability, not from any real danger to the transom. By warning against using the bracket, any claim for damage resulting from the engine slamming down to the transom or engine itself becomes the responsibility of the owner. It really just takes away the potential lawsuits for rotten transom problems and busted engine brackets from being being blamed on the engine design. <br /><br />There is a danger that poor road conditions (potholes and debris) could result in a manually locked engine(No P/T) comming loose and slamming down. I have seen enough of those to encourage the use of any device to secure an engine in the up position. Or, if you have enough clearance, leave it down. It also true that P/T systems do not provide a 100% safe lock in the up position. While the trim section of the P/T system is virtually impossible to force, the tilt section is just not designed for high stress. So...It is a good idea to take the stress off of the P/T when it is fully raised.

 

[dafox99]

Re: Trailering with motor tilted down or up?

I couldn't resist weighing in. We should have picked a topic less emotionally charged, like religion or politics.<br /><br />So, if you have an old motor, like me ('65 40hp), the three options are:<br /><br />1. Use the motor tilt pin. No way .. it will shear. It wasn't designed for that.<br /><br />2. Trailer with the motor down. Maybe, but I could hit something. Why would I risk that?<br /><br />3. Use a transom saver. Seems like a misnomer. In any case, I'm not concerned about my transom .. I'm using it to save the motor. I understand the idea is the applied forces to all that weight haning out there (large polar moment of inertia) puts a hell of a torsion on the transom, but, in this case, I think the tilt pin in shear may be the weak link.<br /><br />The last time a touched an outboard professionally (I sound like a hooker), was in '82, so I'm horribly rusty on this one, but if you have hydraulics, I seem to remember a tilt mode (faster, lower pressure), and a trim mode to be used under power. But, back then, there was a little "tilt" lever. We tilted up, plopped that lever down, and tilted back down so the hydraulics held the motor firmly against this device specifically designed for safe trailering. That was clearly the way to go. Are those levers gone now? If so, I don't think the "tilt" hydraulics are designed to hold a bouncing motor going down the road if the arugument is to just tilt it up and go. If this is so, I guess I'm hearing that if the tilt doesn't hold, the motor will just bang down on the trim pistons mounted to a transom. So, the argument is over whether we will damage the motor/pistons/transom if this happens? Well, on paper, not a chance, from what I can tell from a very quick going-over of the probable loads (even the impulse loads), but I guess, I still wouldn't want my engine slamming down, and possibly hitting the l/u if the "tilt" gave out. It's certainly not good for anything. All of this is just to say, why not use the saver? It's $20.

 

[TOHATSU GURU]

Re: Trailering with motor tilted down or up?

How about "trailering bracket"?

 

[Pony]

Re: Trailering with motor tilted down or up?

Are some of the forces reduced while the boat is under way.....being that the motor is being "pushed" towards the back of the boat? I ask only because I had a motor shut down at WOT and the force of the water resistance destroyed the hydrolics.......If you hit some tracks or a pothole hard enough, is that force capable of the same thing if it happens enoug?? I really am asking, I would like to know.

 

[TOHATSU GURU]

Re: Trailering with motor tilted down or up?

Yes.

 

[itstippy]

Re: Trailering with motor tilted down or up?

I dunno that an upright motor produces a vertical force on the transom, whereas a tilted motor has leveraged motor weight twisting the transom. Not my 1963 Bigtwin. With that motor the weight is distributed evenly when the motor is tilted up. The weight of the powerhead is in front of the fulcrum, the lighter but more leveraged weight of the lower unit is behind the fulcrum, and it balances perfectly. I can mount it on a puny motor stand no problem as long as it's tilted up. But if I set the motor to the vertical position the fulcrum is off center and the majority of the motor's 145# weight is leveraged to pull the transom outward. A puny motor stand tips over and I use profanity.<br />The same is true of my smaller outboards (all pre-1975). Perhaps modern outboards with T&T are balanced when upright? I trailer my old outboards tipped halfway up, resting on a 2X4 under the swivel bracket, and double-bungied in place. Like davef I DO NOT trust the motor tilt pin but I want the motor tipped up.

 

[dafox99]

Re: Trailering with motor tilted down or up?

I think where the torsion would come in while tilted is that, when trailering, the transom gets a forward and reverse component as you bounce, break, start, stop, etc. When you get to moving around, The forces due to acceleration and mass will start trying to move the "balanced" motor. The length of the moment arm, or leverage, changes as it is always perpendicular to the force, which now has a fore/aft component, instead of just "down" due to gravity. So, in theory, if your motor stand went only up and down at any rate (even bouncing), your tilted motor would remain balanced (if perfectly balanced). If it had wheels and you started to move it fore and aft, the balanced engine would gain some torsion component and fall (or try to shear your pin if it's in). I'd say the only exception to this is if those dang engineers balanced it in the "x" direction when tilted as well as the "y" (up and down). Again .. lot of thinking around what seems to be a good idea of some trailering bracket (my dad used the 2X4 bungie setup as well!)

 

[itstippy]

Re: Trailering with motor tilted down or up?

Thank you davef; I understand the discussion better. My Bigtwin in full tilt up position bouncing over RR tracks would not be a problem (up/down), but trailering at 25 MPH and slam on the brakes I'd get a LOT of stress on the transom. Much more than if the motor were down.<br />I'm gonna stick with my half-tilt on 2X4 and bungies. Rides nice.

 

[walleyehed]

Re: Trailering with motor tilted down or up?

On my speedboat, I trim the motor up until I am sure it will clear any road debris. I do not use a transom saver. When you run my boat at WOT with the motor trimmed up for speed, the strain on the hydraulics and transom far exceed any the trailer could impart, thus a transom saver is unnecessary! <br />

Right off of Mercury marine's site;<br />Trailer your boat with the outboard tilted down (vertical operating position). Shift the outboard to forward gear. This prevents the propeller from spinning freely. If additional ground clearance is required, the outboard should be tilted up using an accessory outboard support device. Refer to your local dealer for recommendations. Additional clearance may be required for railroad crossings, driveways and trailer bouncing.<br /><br />IMPORTANT: Do not rely on the power trim/tilt system or tilt support lever to maintain proper ground clearance for trailering. The outboard tilt support lever is not intended to support the outboard for trailering.

 

[JasonJ]

Re: Trailering with motor tilted down or up?

My curiosity is why havn't they built tilting mechanisms that can better withstand trailering? The older V6 Mercs have a beefy tiltlock that would take an act of congress to break, but others are quite flimsy. Sometime in the past someone has rewelded and beefed up the tilt lock on my Merc I6, so I never worry about it, but I would think the outboard manufacturers would include a support device if they really wanted you to use one. Instead, they basically leave us twisting in the wind, having to guess whether we need a support device or not. <br /><br />I see what Walleye wrote, but how many boat dealers tell their purchasers about this potential problem before they trailer their shiny new rig off the lot?

 

[walleyehed]

Re: Trailering with motor tilted down or up?

I talked with one of Mercury's general managers this am, and he agreed totally that very few dealers are even capable of properly setting up a boat, as each individual boat is different, and each dealer/tech is different, and that in no way should, or could a consumer consider their new boat set up 100% perfect, and should expect to make some changes in rigging and engine set-up to get the max potential.<br />I asked him his thoughts about transom savers...<br />His response was "I wouldn't leave home without one".....<br />He did get into some theory on these That I had not thought about, and to simplify what he said, notice the upward angle of the transom saver to the engine when installed...when the engine is pulled down tightly against this, gravitational forces causing transom flex have been stopped, as the angle at which it's placed will not allow any downward movement of the entire engine-not just the lower unit, as it tries to compress the transom saver....<br />He also noted the dealers that handle Merc owned boat and engines, are supposed to supply a transom saver with the new package if the rig was not built or intended to be trailored with the engine in the Verticle position as would be common with a pontoon boat.

 

[surlyjoe]

Re: Trailering with motor tilted down or up?

I have insurance for everything else in my boring life that I pay for monthly, A one time $20 premium on my newly restored motor and transom seems ridiculously cheap!

 

[E_S_A_D]

Re: Trailering with motor tilted down or up?

I didn't want to post a new thread, so here's my related question:

I just bought an old 1972 Tri Hull with a 50 hp Johnson Outboard. There is no mechanical or hydraulic trim, just good ole' elbow grease to lift the engine to the lock position, then disengage.

If I'm towing, which I will be this weekend- do I need to do more than just put it in the 'lock' position? What should I use?

 

[E_S_A_D]

Re: Trailering with motor tilted down or up?

I didn't want to post a new thread, so here's my related question:

I just bought an old 1972 Tri Hull with a 50 hp Johnson Outboard. There is no mechanical or hydraulic trim, just good ole' elbow grease to lift the engine to the lock position, then disengage.

If I'm towing, which I will be this weekend- do I need to do more than just put it in the 'lock' position? What should I use?

To add to this question... I just got my trailer hitch added to my vehicle- it seems as if the ball is awfully close to the vehicle. It was professionally installed, but only a couple inches from the bumper of the vehicle... IS this okay?

 

[Home Cookin']

Re: Trailering with motor tilted down or up?

Personally, I'd just trailer on the lock if it seems to be in good shape (I assume it's a flip-down solid metal fitting you use when you tilt the motor up to launch, moor, etc.) Others will disagree. The topic has been debated ad nauseum here. But so far, not one person has reported an incident of the tilt bracket failing.

Having the trailer ball close in is OK. But watch out for the corners of the bow of the boat hitting the corners of the car, on a tight backing turn.

Yes I know it's an old thread. Next time, i think the mods would prefer a new one, especially since you are raising new questions.