Towing Long Distances with outboard Attached

smallribber · 19 July 2020, 18:09

Do you think that towing a Honwave T38ie with a 20hp 4 stroke on the back all on a Proper trailer designed for Sibs where the Transom is over the bunks so fully supported is wise or do you like to tow long distances with the outboard in the tow vehicle. I am thinking about possible damage to the transom and where it connects to the boat etc.

Also if there is sufficient clearance do you prefer to tow with the outboard down or up

ShinyShoe · 19 July 2020, 20:45

Are the forces really higher from bouncing on a trailer than ribbing?

Peter_C · 19 July 2020, 20:54

I modified a sprung transom saver to support the outboard tipped up, but not on the locks. When stored the outboard was supported by blocks under the skeg in the vertical position to take some of the weight off the transom.

smallribber · 19 July 2020, 21:09

Quote:

Originally Posted by ShinyShoe

Are the forces really higher from bouncing on a trailer than ribbing?

I was thinking the same..... More Bounce on the water however I think but much more speed and sudden impacts against solid on the road.

SixtyNorth · 19 July 2020, 21:15

Not sure what kind of distances you have in mind but you may also want to consider the security issue. If not bolted on, keeping the outboard in the car's boot may be more secure if you expect to leave the boat for a time e.g. parked overnight or just at a service station while you eat.

Maximus · 19 July 2020, 22:14

Quote:

Originally Posted by ShinyShoe

Are the forces really higher from bouncing on a trailer than ribbing?

Debatable..but I'd say potentially yes...an engine being towed on the Transom.. over many hours on poor roads...encountering Pot Holes,Drain Covers, Traffic Calming ,measures ect or even potential blowouts...is much better soundly secured to help counter the forces and potential cantilever effect on the Transom whatever IMO.
Forces at Sea I would suspect are much evenly distributed over the whole Hull even when taking air..when you should be landing Stern first anyway and by so doing cushioning the landing

Pluss the engine is vertical (or nearly) in use!.. dynamically minimising the Cantalever effect on the Transom.

The larger the engine the more forces at work...my 250 V6 is put lowish down (still with plenty of Ground clearance) angle clamped with a large piece of shaped soft wood on full lock with Hydraulic trim (which bites deep into wood)...and also strapped diagonally to Trailer rails with friction ratchet straps x4 -two on each side in opposition.
Done thousands of miles like this over the years and it works well.

billows · 19 July 2020, 22:55

The user manual on my 3.5-AE warns against towing with the engine mounted

Maximus · 20 July 2020, 09:19

Quote:

Originally Posted by billows

The user manual on my 3.5-AE warns against towing with the engine mounted

In that case I'd take their advice!

jeffstevens763@g · 20 July 2020, 09:56

i do with a transom pad, engine lifted resting on an HDPE block and a strap round engine to stop bounce, boat strapped down to trailer at the transom plus bow strap & winch rope nothing for me to tow 700 miles round trip all good so far. if you have plenty of clearance have the engine down and locked

Fenlander · 20 July 2020, 10:30

Two totally different cases here. Fitted with brace like Peter or block and strap like Jeff OK.... resting on tilt mechanism not OK.

Having travelled behind SIBs with 20hp and under motors I'd say yes the stress is worse than in a lively sea.

At sea outboards oscillations are damped by the thrust force and being in water. On a SIB with tilted but unsupported OB travelling on a typical UK road the oscillations can be near constant... made worse by the crude rubber block suspension of many trailers which often transmits a lot of shock to lighter outfits.

Nasher · 20 July 2020, 11:17

Hate those support bars that support the engine leg direct to the trailer.
But I know I'm in a minority with this view.

Could be OK with a smaller engine, but using one on anything with hydraulic tilt/trim makes me wince.

The way I look at it, is that if you connect the engine leg solidly to the trailer and there is any movement or flex between the boat and trailer the force of that movement is transmitted through the Transom bracket and tilt tube of the engine.

To my mind, and again I understand I'm in a minority, it's far better engineering practice to support the leg down to the transom and not worry about any small movement between the boat and trailer.

Nasher

jeffstevens763@g · 20 July 2020, 11:27

agree with nasher and just to make it clear my transom strapped to the trailer, my engine leg strapped to the engine bracket on the through bolt below the trim pin, engine is through bolted to the transom.

The Gurnard · 20 July 2020, 13:34

Quote:

Originally Posted by smallribber

Do you think that towing a Honwave T38ie with a 20hp 4 stroke on the back all on a Proper trailer designed for Sibs where the Transom is over the bunks so fully supported is wise

Perhaps it is worth remembering the Honwave T38 ie has an air floor and inflated tabs that the transom sits on and it will be between the solid transom and the trailer bunks.

As such.. I would be inclined to follow the manufacturers recommendation not to trailer with the engine in place. However Im happy to be corrected by those who have experience of towing airfloors with outboards attached as I have no experience of doing so

smallribber · 20 July 2020, 13:41

Many thanks for all the suggestions.... I am however none the wiser

jeffstevens763@g · 20 July 2020, 14:31

Quote:

Originally Posted by smallribber

Many thanks for all the suggestions.... I am however none the wiser

didnt look at it being an air floor apologies i wouldn't stick it in the boot thats coming from someone who will do anything for ease

Brian · 20 July 2020, 14:32

smallribber,

No, but at least now you are better informed.

The Gurnard · 20 July 2020, 14:33

Im not sure why you are unsure smallribber ..the instructions in the manual are perfectly clear..? Even when written in china

Fenlander · 20 July 2020, 16:42

Above Donny gives the by the book advice for the OP's specific SIB and I have no argument with that.

But just for the general conversation re OB on or off and suport choices...

Interesting that Zodiac/Bombard are happy for up to a 25hp motor to stay on the transom of an Aerotec when trailered... as long as the transom is supported on a bunk and the outboard skeg supported on a trailer brace.

Of course unlike the Honwave the Aerotec transom can be fully supported on a bunk.

smallribber · 20 July 2020, 17:57

Thanks Donny. I am converting a Toyota Previa into a camper van and rather wanted to keep the outboard out of the vehicle. Looks like I will have to put it in the back of the van.

Once at the camping spot however I will put it on and tow it the shorter distances to the water

Fenlander · 20 July 2020, 18:03

>>> I am converting a Toyota Previa into a camper van...

Interesting. Over the past two or three years we have talked ourselves into and out of and almost back into a campervan to fit in with sibbing. Considered both home build and ready made.