Motor position while towing

[browntdb]

I have read many places on the internet that suggest the motors be placed in the down position when towing the boat on its trailer. With Tortuga, I cannot do that because the motors are only about a foot off the ground when down. My album shows the position of the motors resting on their flip down supports. The hydraulic cylinders are extended in this position and I assume supporting the motors from changing position in case of a bump?

I have only towed the boat from Medford OR to Corvallis OR several months ago. We are about to begin our boating this season andI don't want to damage the motors in any way when towing by leaving them in this postion and a hard bump dislodging them. The only other boat I had allowed the motors to be placed in the down position when towed.

Should I worry about towing as shown in the photo? Any alternatives? Perhaps the tilt hydraulics prevent problems?
Thanks,

Terry

[Sea Wolf]

Hello!

Welcome to the C-Brat site!

You'll find this is a very common topic of discussion around here, and one with some differing opinions.

I suggest you go to the Outboards and Systems Forum and look though the topics. A lot of them address this question.

Good Luck!

Joe.

[bluegene]

I believe the issue is stress on the transom. With a 350 lb engine [my 90 hp, 4 stroke] tilted up, the engine acts as a lever arm stressing the transom back and forth. With the engine down, the stress is in an up and down direction instead. The up and down movement doesn't stress the transom like the back and forth does. If you're driving on I5 between Medford and Corvallis, I would think one foot off the highway is enough clearance. I tilt my engine up slightly to get around one foot off the road and lower the engine onto a two by four sandwiched between the shaft and engine bracket so the hydraulics are relieved of holding the slightly elevated position.

[thataway]

There have been several threads on this recently. Generally, the issue is the stress on the tilt cylinder. The transom is made to take the load (consider bucking thru 2 1/2 foot chop at 25 mph.) There is also the issue of road vibration.

I have always used some form of support. Currently I am using MY Wedge http://www.m-ywedge.com on the C Dory 22 with a Honda 90 and a "Transom Saver"--a spring loaded square tubing between the lower unit and the trailer aft cross member. I have also used 2" dowel rod and pieces of 2 x 4.

There are those who use the small tabs on the side for support. Many manuals note that these are only for working on the motor, and not for trailering. I have seen several break--and you can imagine what happens to the lower unit in that case.

[Sunbeam]

I'm on the same page as Thataway.

1) I feel like the best position for the motor when towing is fully down, IF you can achieve that without hitting the ground. I can tow with my kicker this way, now that I have it on the Mini-Jacker -- but not the main (it would hit the ground).

2) So I have to tilt the main (Yamaha 80). The manual says in no uncertain terms not to use the tilt holder-upper-lever. That is for when working on the engine in a static (non-towing) mode. It's also not supposed to rest on the tilt cylinder alone (stresses it). So that leaves propping it up somehow.

a) Transom saver that goes to trailer. Supposedly not good because trailer flexes differently than engine and imposes stresses and movement (I have not used one).

b) M-Y Wedge. I bought one of these and thought it was really slick, but I had a failure of mine on my last trip. It deformed and worked its way out. I *think* my motor wasn't damaged. My current thought is that the instructions tell you to put it in backwards, but... I'm not sure (?). I think I had it in "backwards" from the instructions for my first 5,000 miles of towing, and it worked beautifully. Then I read the instructions and realized I had it in 180º opposite from what they show, so for my next trip I put it in right, and it deformed and failed. So... not sure what to think. It does seem like a great product.

c) Dowel or piece of wood. My motor is shaped better for a slightly modified 1" x 2" type piece of wood than a round dowel. I made one of scrap at a rest area when I found the deformed M-Y Wedge and the engine towed perfectly with it the next few thousand miles. I'm about to head out again and it will be with a similar piece of wood, only made of something better than the ply scrap I had at the rest area. I note that the parts on my motor bracket that are contacted by the "board" are pretty sturdy looking. So while the resilience of the M-Y Wedge seemed like a good idea, I don't think I need it on my particular set up (I was told that certain castings can break, but I have not looked at that many other ones).

Many others have a lot more miles under their belts than I do, but this is over around 10,000 miles of towing, so at least not just "around the block." However, that said, I only have my tow motors' worth of experience, as previously I never towed anything with an outboard left on the transom.

Sunbeam

[ssobol]

My lower unit sits pretty close to the ground when the motor is down (couple of inches). The previous owner towed the boat around for 5 years using the tilt lock and never had a problem. I put a piece of 2x4 across the top of the transom part of the mount and bring the motor down till the wood is snug. This gets the lower unit well up.

If you look at the way the motor sits on the transom, even in the down position, the CG of the motor is about a foot aft of the transom and about even with the top (for the motors used on a CD-22). The dead weight of the motor and any acceleration of the motor is going to result in a torque on the transom. It will try to twist the transom backward off the boat. If the motor is tilted up, the CG will move forward and you will relieve some or all of the torque from the dead load of the motor. Vertical motions of the engine (e.g. road bump) will be a more vertical load on the transom and less of a torque.

It is possible to have a transom structure that is good at handling the aft torque of the motor (in the normal position) but not be so good at handling a forward twisting (as when the motor is tilted up). But designing it this way would be more difficult than just making a beefy structure.

The load placed on the transom during normal operation (say going to WOT from a standstill or hitting a large wave at speed) puts a vastly greater load on the transom than occurs from normal road bumps when trailering. When the engine is at speed you have hundreds of pounds of thrust on a ~2' moment arm. Being able to handle this load results in a transom that is more than able to handle the weight of the motor in pretty much any position.

Any boat where this was actually a real concern is a boat that I wouldn't want to be on.

My $.02.

[colbysmith]

On my past boat, an I/O, they made little plastic sleeves to fit over the cylinder to take the load off the hydraulic trim. Too bad they don't make something like that for the outboards. I trailered my CD-22 with Merc 115 Hp EFI 4-stroke quite a bit last summer. I leave it in the down position, and probably have a foot clearance between the skeg and the ground. Definitely not much more than that. I have pulled out of various driveways and if I'm not sure, I've gone pretty slow. So far I have not hit anything. I have an Ez Loader trailer and the wheels are a ways back. I'm sure the skeg has come close, but so far, no scrapes in the bottom of it. Unless you are going over some steep dips, I don't think you will have a problem if you have a foot of clearance. Colby

[T.R. Bauer]

Down.....but I agree with Bob, I really don't think the boat really cares. The lift cylinder is a different story.

[jack keifer]

Since we live in Boise, we tow everywhere and our boat spends huge amounts of time on the trailer. The way I approached the issue was to use what Honda calls the transom angle adjusting pin. It came with one on the 75 on our 22 cruiser, and we trailered with pin in the top hole and never had a problem with dragging the skag on anything over 10 plus years, and many miles. I found it to be quite handy as one does not have to get under the boat to attach a travel support, and still got the pressure off the tilt cylinders. On the water I store it in the bottom hole and it never interferred with trim. It worked well enough that even though the 50 on the C-Squirt didn't come with the pin, I bought one and use it the same way. Another item on my check list is to tow with the directional control in gear to prevent the wind from rotating the prop.
Cheers
Jack

[Captains Cat]

If you use a M-Y Wedge, be very careful! The rubber is hard enough to crush the metal top of your trim/tilt cylinder if you forget it's there and power tilt your engine(s) down. Don't ask me how I found that out!

Charlie

[thataway]

Colby Smith--the M Y Wedge is a heavy duty item which fits between the tilt cyl and the motor, similar to what you describe.

I am using Charlie's wedge--but I am careful to remove it before using the boat. Part of prep for the water is a walk around, to check the transom drain plug, that all straps aft are off the boat, to check the prop, to check the trim tabs, transducers and motor mounts. During this walk around I remove the M Y Wedge using the motor mounted tilt/trim switch.

[Captains Cat]

[Wefings]

These work well . DO NOT TOW ON THE MOTOR LOCKS!
It says that in most manuals . They are for working on the trim and tilt units. We have replaced a number of bent and broken ones . A two by four wedged in is a simple solution but the Yamaha part or similar is fine .
Marc

[colbysmith]

As I mentioned earlier, I don't use anything on my outboard. It's a single Merc 115 hp, and I just leave it down. I have had no problems trailering that way, and I think I'm actually less than 12" off the ground. Perhaps only 9 or 10".

[bridma]

I tow with the engines down. If you look at the first pic in my "Launch Day" album, you will see I have about 18" clearance. Part of the underneath of my trailer is lower to the ground than my props.

Martin.