SIB, leaving motor on transon while transporting?

[Slayer33]

So I've always just kept my motor in my vehicle when transporting... this was when I had a small 9.8hp 2 stroke that weighed 60lbs.

I just picked up my new 2017 Mercury 20hp 4-stroke and I'm not going to lie.. its fairly heavy at around 115lbs.

I have gotten 2 opinions in regards to transporting.. 1st was from a zodiac dealer who said there is no issue leaving the motor on the transom in the "down" position when transporting as long as you have clearance below.. which I do. But the person I spoke to at Basspro who delivered my new motor said he wouldn't leave it on.. and he has a 12' inflatable....

So which is it? Obviously I would rather leave it on the transom if I can vs. taking it on and off...

I know if the roads are bumpy where I'm going there will be more force on the transom.. but in reality isn't there going to be the same if not more force put on the transom when I'm flying around in the water?

[jeffstevens763@g]

I leave my 25 Suzuki on all the time I have a keel pad to support the transom, I have to lift my engine for clearance so I have a piece of HDPE rod between the bracket and engine to support and take weight off the tilt mechanism then a ratchet strap from the engine leg to the trailer done it this way for years.

Cheers

[rossymtb]

My last setup 3.8m & 25hp Johnson.
I left it on while transporting. in the up position with a chock of wood so it wasn't on the tilt mechanism.
And my trailer was supposed under the transom.

It was fine for two years i had it. And hundreds of country miles.
Soon as i sold it the new owner broke the engine bracket.

[Rover310]

Originally Posted by Slayer33

So I've always just kept my motor in my vehicle when transporting... this was when I had a small 9.8hp 2 stroke that weighed 60lbs.

I just picked up my new 2017 Mercury 20hp 4-stroke and I'm not going to lie.. its fairly heavy at around 115lbs.

I have gotten 2 opinions in regards to transporting.. 1st was from a zodiac dealer who said there is no issue leaving the motor on the transom in the "down" position when transporting as long as you have clearance below.. which I do. But the person I spoke to at Basspro who delivered my new motor said he wouldn't leave it on.. and he has a 12' inflatable....

So which is it? Obviously I would rather leave it on the transom if I can vs. taking it on and off...

I know if the roads are bumpy where I'm going there will be more force on the transom.. but in reality isn't there going to be the same if not more force put on the transom when I'm flying around in the water?

No, the transom would be subjected to much more force during trailering with the motor down on bumpy roads than it would be when the boat is in the water and underway.

Of course you could remove the motor whenever you're trailering the boat, but the reality of doing that is 115 lbs. is a lot to man handle, especially by yourself.

The other option, leaving the motor on the transom isn't a problem as long as you don't trailer it with the motor in the down position. The reason is that in the down position the weight of the motor is exerting a lot of horizontal leverage on the transom. Whereas when the motor is tilted up over the transom, the weight of the power head is centered vertically over the transom.

And of course there is the possibility of clearance issues with gear case skeg and the road surface, especially when driving over speed bumps etc. with the motor in the down position.

That said, one thing you really need to do when transporting with the motor tilted is to use some sort of a transom support*, which mounts between the motor leg (or gear case) and the rear most trailer crossmember, so as to secure the motor in the tilted position. What you don't want to do is use the motor's own tilt bracket to keep it in the tilted position while trailering... a few big bumps in the road can quickly damage the motor's tilt bracket.



* You could make one yourself using a piece of 2x4, or buy one designed for the job. This one is made by Attwood Marine, and sells for around $50 - $60 USD...

[69cmw]

Originally Posted by Rover310

leaving the motor on the transom isn't a problem as long as you don't trailer it with the motor in the down position. The reason is that in the down position the weight of the motor is exerting a lot of horizontal leverage on the transom. Whereas when the motor is tilted up over the transom, the weight of the power head is centered vertically over the transom.

Bollocks

[jeffstevens763@g]

Originally Posted by 69cmw

Bollocks

+1
with a keel pad/transom saver on the transom/engine and the tube bunks past the transom i would much prefer the engine in the down position if i had clearance, most of the weight is then vertically down,there's a certain amount of shock absorption in the tubes to help.the main issue is on rough terrain where you just have to drive accordingly all IMO & experience.

[Slayer33]

this is quite the debate... which is why I'm glad to have posted this question... I don't know which is better, but I know for sure that I'll make a support to go from the trailer to the bottom of the transom, and then I'll either:


A. leave it in the down position since I have lots of clearance


or


B. tilt the motor and get a transom saver...


I can see how the thought of using a transom saver would distribute the weight (albeit not like 50/50, probably more like 80/20, 80 being on the transom) across the transom and the support bar

[jeffstevens763@g]

simple enough to make one for the transom if you dont have a supplier: thumbs:

[Rover310]

Originally Posted by 69cmw

Bollocks

Really, bollocks? Brilliant reply.

Why do you think that the vast majority of small boats you see being trailered do so with the motor tilted up, and are almost always using some sort of a transom saver to support the motor leg?

I'll say it again... the reason for trailering with the motor tilted up is that it places the weight of the motor more vertically over the transom, instead of the weight hanging off the transom. Anyone with a basic understanding of simple physics would know that. But don't take my word for it... google it.

[69cmw]

Originally Posted by Rover310

Really, bollocks? Brilliant reply.

Why do you think that the vast majority of small boats you see being trailered do so with the motor tilted up, and are almost always using some sort of a transom saver to support the motor leg?

Bollocks, only reason to tilt it up is to stop it hitting the deck ...

I'll say it again... the reason for trailering with the motor tilted up is that it places the weight of the motor more vertically over the transom, instead of the weight hanging off the transom. Anyone with a basic understanding of simple physics would know that. But don't take my word for it... google it.

I'll say it again, bollocks ....

[Pikey Dave]

Originally Posted by 69cmw

I'll say it again, bollocks ....

Yup[emoji106]

[Rover310]

Originally Posted by 69cmw

I'll say it again, bollocks ....

Once again, brilliant reply pal.

[Slayer33]

I'd like to see some kind of stress analysis done on this.. would be interesting to see the results one way or another..

[Pikey Dave]

Originally Posted by Slayer33

I'd like to see some kind of stress analysis done on this.. would be interesting to see the results one way or another..

You don't need to, you could sketch it out, add the weights & do some simple moment calculations. The upshot is, the forces on the transom during use on the sea, will exceed any forces exerted by "normal" trailering on a suspension equipped trailer. Using a transom saver tied to the trailer, especially on a SIB will (IMO) make the situation worse.

[Seaflyer02]

Originally Posted by Pikey Dave

You don't need to, you could sketch it out, add the weights & do some simple moment calculations. The upshot is, the forces on the transom during use on the sea, will exceed any forces exerted by "normal" trailering on a suspension equipped trailer. Using a transom saver tied to the trailer, especially on a SIB will (IMO) make the situation worse.

Wondered how long before common sense prevailed.

If the boat / engine is so delicate that you must trailer the engine tilted because of the load on the transom, then you should never use it with the engine powering it on the water IMHO

[69cmw]

Originally Posted by Seaflyer02

If the boat / engine is so delicate that you must trailer the engine tilted because of the load on the transom, then you should never use it with the engine powering it on the water IMHO

[emoji106]

[The Gurnard]

Originally Posted by Rover310

I'll say it again... the reason for trailering with the motor tilted up is that it places the weight of the motor more vertically over the transom, instead of the weight hanging off the transom. Anyone with a basic understanding of simple physics would know that. But don't take my word for it... google it.

Hi Rover310

Its normally good forum practise to give a link or provide some reliable information to any opinion posted..it saves any doubt. If you can do so..then perhaps folks will accept your advice easier

An example is this from my SIB instruction manual..I have a few more manuals and they ALL say the same. Hope that helps the OP with an answer.

[beerbelly]

and I was pissed off cos theres nowt on telly tonight

[jeffstevens763@g]

Originally Posted by Pikey Dave

You don't need to, you could sketch it out, add the weights & do some simple moment calculations. The upshot is, the forces on the transom during use on the sea, will exceed any forces exerted by "normal" trailering on a suspension equipped trailer. Using a transom saver tied to the trailer, especially on a SIB will (IMO) make the situation worse.

You beat me to it Dave really is basic fulcrum & levers if you secure your engine and stop any movement and support it there will be no problems I've towed boats thousands of miles this way with no problems ever. Never used one of the bar type savers nor would I don't like the idea of the clamp on the leg for various reasons IMO

[Pikey Dave]

Originally Posted by beerbelly

and I was pissed off cos theres nowt on telly tonight

Owt's better than The Nightly Show[emoji849]