Reply
 
Thread Tools Search this Thread
 
Old 22 February 2012, 04:42   #51
Member
 
Country: UK - England
Town: Necastle
Make: Zodiac
Length: 5m +
Engine: outboard
Join Date: Feb 2012
Posts: 15
My unscientific, limited experience take on this is I have always towed engine up without thinking about it till this thread.... Having given it some thought and read though all this I will continue to do so.
The loads on the transom when blasting through waves to get to a casualty must surely be higher than a toddle at 60mph up a motorway on a trailer equipped with suspension and inflatable tyres? With the engine tilted the centre of gravity is moved above the transom so the loads are more evenly distributed than with all the motor hanging off the back. Anyway that is where I have got to having given it a bit of thought but I am prepared to be wrong (I usually am!).
__________________

__________________
TwoBob is offline   Reply With Quote
Old 22 February 2012, 04:55   #52
Member
 
busybee's Avatar
 
Country: UK - England
Town: Portsmouth Area
Boat name: Busy Bee
Make: Ribcraft
Length: 5m +
Engine: Suzuki
Join Date: Jan 2012
Posts: 107
I have spoken to Ribcraft via email, the official word was "Most people just rely on the Hydraulics and tow with the engine up, which is fine. Another method to use is to just use a decent size block of wood between the engine bracket to trim the engine down on to, for long journeys this my preferred method.
Whichever method, don’t use the up lock on the saddle bracket, they’re only for use when the boats are afloat."
I am thrilled with quality of my Ribcraft boat and they are a very professional outfit
and I would recommend them to anyone and as the boat builder and engine supplier I shall do as they recommend, they know far more than me.
__________________

__________________
busybee is offline   Reply With Quote
Old 22 February 2012, 07:37   #53
Member
 
Country: UK - England
Town: southampton
Make: ribeye
Length: 6m +
Engine: 100
Join Date: Jul 2006
Posts: 194
My thoughts are, that the engine tilted up creates a nasty object for a rear end shunt. Dread to think what a motor cyclist would look like slamming into the back of the skeg

I suppose people put buckets over the prop or tie red cloth as protection/warning, still, having read through most of this, I will keep the engine down as much as possible in future.
__________________
ribber is offline   Reply With Quote
Old 22 February 2012, 08:59   #54
Member
 
Leapy's Avatar
 
Country: UK - England
Town: Sheepy Parva
Boat name: Sadly Sold
Length: no boat
Join Date: Sep 2008
Posts: 1,728
Quote:
Originally Posted by ribber View Post
My thoughts are, that the engine tilted up creates a nasty object for a rear end shunt. Dread to think what a motor cyclist would look like slamming into the back of the skeg
Skeg...artic...tractor...refuse truck...
__________________
Leapy is offline   Reply With Quote
Old 23 February 2012, 15:29   #55
Member
 
hadd's Avatar
 
Country: UK - England
Town: Manchester
Boat name: "mr Jingles"
Make: Ribcraft
Length: 5m +
Engine: 130 Etec
MMSI: 235074968
Join Date: Jun 2009
Posts: 1,388
RIBase
I've just found this in the Evinrude etec Operator' guide they call it a TRAILERING BRACKET
Attached Thumbnails
Click image for larger version

Name:	IMG_0483.jpg
Views:	126
Size:	137.9 KB
ID:	65846   Click image for larger version

Name:	IMG_0482.jpg
Views:	120
Size:	116.9 KB
ID:	65847   Click image for larger version

Name:	IMG_0481.jpg
Views:	117
Size:	147.9 KB
ID:	65848  
__________________
hadd is offline   Reply With Quote
Old 23 February 2012, 16:14   #56
Member
 
Anchorhandler's Avatar
 
Country: France
Town: Huisnes sur Mer
Boat name: Raufoss
Make: Avon
Length: 4m +
Engine: Mercury 50
Join Date: Sep 2010
Posts: 789
Quote:
Originally Posted by TwoBob View Post
My unscientific, limited experience take on this is I have always towed engine up without thinking about it till this thread.... Having given it some thought and read though all this I will continue to do so.
The loads on the transom when blasting through waves to get to a casualty must surely be higher than a toddle at 60mph up a motorway on a trailer equipped with suspension and inflatable tyres? With the engine tilted the centre of gravity is moved above the transom so the loads are more evenly distributed than with all the motor hanging off the back. Anyway that is where I have got to having given it a bit of thought but I am prepared to be wrong (I usually am!).
Nope, i'm an engineer by nature and my philosophy is the same, instead of allowing the outboard to put a rotational torque on the transom i always tow with the outboard up.
I appreciate the forces involved taking into account shock loading etc and prefer to see as close as possible to a near vertical force acting downward directly above the transom.
I belieive that the shock loading an outboard/transom encoutesr when being towed in the downward position is more severe than the vertical loading it recieves when the boat is actually in the water (the water has far more give in it that the road)...especially on our crap UK roads

Simon
__________________
C'est pas l'homme qui prend la mer, c'est la mer qui prend l'homme....
Anchorhandler is offline   Reply With Quote
Old 24 February 2012, 04:28   #57
Member
 
Country: UK - Scotland
Boat name: Wildheart
Make: Humber/Delta Seasafe
Length: 5m +
Engine: Merc 60 Clamshell
MMSI: 235068449
Join Date: Apr 2007
Posts: 4,610
As it's friday and I'm in a mischevious mood......

Vertical force on the transom I assume we are all talking a force parallel to the face of the transom as opposed to actually vertical?

So, the force imparted by the pothole is applied to the end pivoted lever (the trailer chassis rotating about the towball) which will impart the force t othe engine in a 6-ish (for a 5.something m boat) m radius arc. The actual force excerted will depend o nthe transom rake and the baot's position on the trailer relative to the towball.

Now, how high do most ribs sit relative to the ball? If we draw an imaginary line along the centreline of the boat forwards, it will more than likely clear the car by quite a distance. Now move that line down vertically until it intersects the ball. That is the point where the transom will geometrically see a "pure vertical" (or more accurately paralell to the transom face shunt) As that eoud probably have the powerhead at or below the road surface in most cases, the geometry puts the transom out o nthe tangent to the rradius. Thus any movement will impart a small forward motion. I reckon that "pothole force" is likely to try & lever the transom backwards even just a litle bit, regardless of the engine position....



Let;s face it, the engine regardless of how it's "parked" is not perfectly balanced. The trialer wheels see random pothols, so the forces are anything but vertical - there's twisting & all sorts going on as well as one wheel hits a hole. Bottom line is the piddley "hold it u" bracket is never going to survive, so it needs braced. Whether by wood, hydraulics or whatever.
__________________
9D280 is offline   Reply With Quote
Old 24 February 2012, 05:58   #58
Member
 
Country: UK - England
Town: Dorset & Hants
Boat name: Streaker/Orange
Make: Avon/Ribcraft
Length: 4m +
Engine: 50Yam/25 Mariner
Join Date: Apr 2007
Posts: 5,551
Quote:
Originally Posted by Anchorhandler View Post
Nope, i'm an engineer by nature and my philosophy is the same, instead of allowing the outboard to put a rotational torque on the transom i always tow with the outboard up.
I appreciate the forces involved taking into account shock loading etc and prefer to see as close as possible to a near vertical force acting downward directly above the transom.
I belieive that the shock loading an outboard/transom encoutesr when being towed in the downward position is more severe than the vertical loading it recieves when the boat is actually in the water (the water has far more give in it that the road)...especially on our crap UK roads

Simon
Seconded .....with the engine up the mass of the engine block etc is vertically above the transom as opposed to 'hanging off' it - even a big bounce on the trailier just tries to vertically compress the transom as opposed to twist/torque the transom off the back of the boat.

I've always towed engine up, with the lock/support in place but only lightly loaded letting the hydraulics take the load...
__________________
PeterM is offline   Reply With Quote
Old 26 February 2012, 15:53   #59
RIBnet supporter
 
gotchiguy's Avatar
 
Country: UK - England
Town: Dinard, Brittany
Boat name: Into the Red
Make: Osprey Vipermax
Length: 7m +
Engine: Evinrude E-tec 250HO
MMSI: 235 076 114
Join Date: Apr 2009
Posts: 1,948
RIBase
Quote:
Originally Posted by willk View Post
A touch of Vorsprung durch Technik wouldn't go amiss in the outboard world, eh Kerny?
A German guy approaches a prostitute.
"I vish to buy zex vit you"
"OK" says the girl, "I'll charge 50 an hour".
"Ist goot, but I must varn you, I am a little kinky".
"No problem", she replies cautiously, "I can do a little kinky". So off they go to the girls flat, where the German produces four large bedsprings and a duck caller. "I vant you to tie ze springs to each of your limbs". The girl finds this most odd, but complies, fastening the springs to her hands and knees.
"Now you vil get on your hans und knees".
She duly does this, balancing on the springs.
"You vill please blow Zis vistle as I make love to you."
She finds this odd, but figures its harmless, and the guy is paying. The sex is fantastic. She is bounced all over the room by the energetic German, all the time honking on the duckcaller. The climax is the most sensational that she has ever experienced, and it is several minutes before she has recovered the breath to say:
"That was totally amazing, what do you call that?"
"Ah", says the German, "Four-sprung duck technique!"
__________________
gotchiguy is offline   Reply With Quote
Old 26 February 2012, 16:02   #60
Member
 
kerny's Avatar
 
Country: UK - England
Town: Ashton-under-Lyne Lancs
Boat name: IMOGEN
Make: Air-Craft 5.4
Length: 5m +
Engine: Etec 60
MMSI: 235087492
Join Date: May 2010
Posts: 7,040
RIBase
Send a message via Skype™ to kerny
Quote:
Originally Posted by hadd View Post
I've just found this in the Evinrude etec Operator' guide they call it a TRAILERING BRACKET
Just double checked my Etec manual and under trailering it says... Trailer your outboard in a vertical position. If your trailer does not provide adequate road clearance, tilt the outboard as needed and support the outboard with an accessory trailering bracket.

Notice... use of tilt lock lever when trailering may cause damage to outboard.

Andy I presume yours as you say is a trailering bracket and is fine

I haven't got one on mine and I have wrongly been using the tilt lock while towing

I have tried googling to find out who sells them but nothing coming up, any Etec owners know where I can get one.... thanks.
__________________

__________________
kerny is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off





Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -5. The time now is 19:54.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.