Reply
 
Thread Tools Search this Thread
 
Old 21 April 2016, 03:25   #11
Member
 
Country: UK - England
Town: Sussex
Boat name: Bombard, Y-162
Make: Aerotec 380, Y-Class
Length: 3m +
Engine: Mercury Mariner 15hp
Join Date: Jul 2010
Posts: 2,692
Quote:
Originally Posted by Gwozhog View Post
The engine will do more abuse WOT on the water to the transom than it could ever do on a trailer.
Why??
__________________

__________________
Max... is offline   Reply With Quote
Old 21 April 2016, 09:07   #12
Member
 
Country: USA
Town: Point Blank,TX
Boat name: Just Blown
Make: Achilles 2 of them
Length: 3m +
Engine: Yam 8&15hp Nissan 15
Join Date: Oct 2015
Posts: 43
Quote:
Originally Posted by Max... View Post
Why??
Fantastic question and I would love to answer it. I pretty sure nobody is doing what the general lee is doing when they trailer. Now I'm not sure how you ride around on the water but when I'm WOT and I pass another boat that throws a pretty big roller my SIB occasionally has looked like the general LEE in the pic below. Not sure if you have ever pulled a skier behind your SIB either but it has quite a bit of force on the transom too. So if your boat is properly inflated on the trailer and you are keeping all six of your wheels on the ground and not breaking any laws on the roadways you should not have a problem trailering with an outboard on the transom. Hope that answers your question.
Attached Thumbnails
Click image for larger version

Name:	image.jpg
Views:	65
Size:	129.4 KB
ID:	112106  
__________________

__________________
Gwozhog is offline   Reply With Quote
Old 21 April 2016, 11:09   #13
Member
 
Country: USA
Town: Oakland CA
Length: 3m +
Join Date: Feb 2005
Posts: 6,653
Generally, when you're on the water, the force on the transom is unidirectional - a twisting force from the prop pushing forward, with the motor mount keeping the motor from flipping backwards. Force is mainly forward on the transom, but may vary as swell is encountered.

On a trailer, the force is bi- or multi-directional, as the motors weight pendulums fore and aft, and side to side, as road irregularities are encountered. It becomes more pronounced as the motor is "balanced" in a raised position with the center of mass perched on top of the transom.

I am not claiming that forces are larger while trailering (though I also wouldn't be surprised if they are), but they are definitely different. I use a transom saver to stabilize the motor and transfer some of that energy to the trailer frame.


jky
__________________
jyasaki is offline   Reply With Quote
Old 21 April 2016, 12:41   #14
RIBnet admin team
 
Poly's Avatar
 
Country: UK - Scotland
Boat name: imposter
Make: FunYak
Length: 3m +
Engine: 2 stroke YAM 20 HP
MMSI: 235089819
Join Date: Sep 2005
Posts: 10,114
Quote:
Originally Posted by Gwozhog View Post
Fantastic question and I would love to answer it. I pretty sure nobody is doing what the general lee is doing when they trailer. Now I'm not sure how you ride around on the water but when I'm WOT and I pass another boat that throws a pretty big roller my SIB occasionally has looked like the general LEE in the pic below. Not sure if you have ever pulled a skier behind your SIB either but it has quite a bit of force on the transom too. So if your boat is properly inflated on the trailer and you are keeping all six of your wheels on the ground and not breaking any laws on the roadways you should not have a problem trailering with an outboard on the transom. Hope that answers your question.
You've not seen British roads! Its certainly possible that the wheels on a sib trailer bounce over potholes, kerbs or speed bumps even with sensible driving.

When it is on the water the boats is supported over a relatively large area, and when landing on water it has a relatively cushioned landing. When on a trailer, many sibs have poor support at the actual transom.

Some SIBs will actually spend longer on the trailer travelling to the water than being used afloat; many of those miles will be at 2-3x the maximum speed on the water and so the frequency of the vibration from towing will be quite different.

The engine itself is partially supported by the water (both through bouyancy and by lift) most of the time, only momentarily is the entire weight of the engine ever acting vertically on the transom.

That said, I'd tow a sib with an engine on the transom, with some extra support
that (a) helped to stop it bouncing around and (b) transferred the load direct to the trailer rather than via the tubes.
__________________
Poly is offline   Reply With Quote
Old 10 June 2016, 12:20   #15
Member
 
Country: Ireland
Length: 3m +
Join Date: Jun 2012
Posts: 28
How far out to sea is it safe to take a 360s yam ?
__________________
cala is offline   Reply With Quote
Old 10 June 2016, 12:42   #16
RIBnet admin team
 
Poly's Avatar
 
Country: UK - Scotland
Boat name: imposter
Make: FunYak
Length: 3m +
Engine: 2 stroke YAM 20 HP
MMSI: 235089819
Join Date: Sep 2005
Posts: 10,114
Quote:
Originally Posted by cala View Post
How far out to sea is it safe to take a 360s yam ?
That very much depends...

This weekend a group of sibs will hopefully travel around 70 miles. They'll never be more than a few miles from shore, although that doesn't mean there is a safe or easy escape plan at the nearest shoreline. They do have the safety of others nearby, and whilst it's not a perfect forecast it is still relatively sheltered.
__________________
Poly is offline   Reply With Quote
Old 10 June 2016, 13:10   #17
Member
 
Country: UK - England
Town: Sussex
Boat name: Bombard, Y-162
Make: Aerotec 380, Y-Class
Length: 3m +
Engine: Mercury Mariner 15hp
Join Date: Jul 2010
Posts: 2,692
Quote:
Originally Posted by cala View Post
How far out to sea is it safe to take a 360s yam ?
As Poly indicates - how long is piece of string?!

Depends on so many factors - experience, crew make-up, bottle, weather, local area, engine size, solo or in a group, rescue services etc - obviously some factors far more important than others. Personally if not in convoy I would not generally go more than a mile or less from the coast as round here the next land 'out' is France so no island hopping etc just coastal hugging and then you can go as far as you like fuel and stamina permitting.

All small SIBs are generally Cat C:

C. INSHORE: Designed for voyages in coastal waters, large bays, estuaries, lakes and rivers where conditions up to, and including, wind force 6 and significant wave heights up to, and including, 2m may be experienced.
__________________
Max... is offline   Reply With Quote
Old 10 June 2016, 13:21   #18
Member
 
Country: Ireland
Length: 3m +
Join Date: Jun 2012
Posts: 28
Thanks Poly and Max, very informed advice, i was really only thinking of 1 or 2 miles max for fishing in good weather.
__________________
cala is offline   Reply With Quote
Old 10 June 2016, 15:09   #19
Member
 
Country: UK - Wales
Town: Cardiff
Make: Avon
Length: 3m +
Engine: 2 stroke
Join Date: Aug 2014
Posts: 852
Quote:
Originally Posted by cala View Post
Thanks Poly and Max, very informed advice, i was really only thinking of 1 or 2 miles max for fishing in good weather.
That's fine and what they are often used for just make sure you have an effective method of communication if you do have an issue.

Marine vhf radio is the norm.
__________________

__________________
HDAV 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 16:32.


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