Don't ask me why I wish to run a seagull backwards but I'm wondering if I advanced the timing 50 Degrees and inverted the rope pulley is there any reason why it wouldn't run backwards? Would the bearings handle a change of rotation? It seems logical.
Cheers Hugo.
Seagull running backwards
Moderators: John@sos, charlesp, Charles uk, RickUK, Petergalileo
-
Ian Malcolm
- Posts: 108
- Joined: Thu Mar 30, 2006 11:42 am
- Location: London, ENGLAND
Dont forget the water pump impeller. I suspect that it will be even less effective than usual running backwards. Also, take a long *hard* look at the gearbox to decide if you are going to need to machine clearance for a proper thrust washer etc. The Prop retaining pin, washer and drive spring will also need redesign. *beefier* pin, some sort of spacer to stop the thrust crushing the spriing etc.
There will be some wear issues with the piston skirt as it bears on one side of the bore during the power stroke and this will change to the other side, but if the bore and piston are in decent condition there shouldn't be any problems
I'd suggest a modified rope spool, with extra slots for reversing and some mechanism with a lever and two detents to move the baseplate between normal and reversed timing. Then I'd probably pay good money to see a video of you going from ahead to astern in a close quarters situation.
(Its the re-wrapping the rope bit when you have to wrap it the wrong way against all your years of developed instinct while your bow is getting ever closer to T-boning the expensive gin palace that would be the best. Might need two addditional camera angles - one for the look on your face, the other for the gin palace's owner in his deck chair with his pink gin in hand!)
There will be some wear issues with the piston skirt as it bears on one side of the bore during the power stroke and this will change to the other side, but if the bore and piston are in decent condition there shouldn't be any problems
I'd suggest a modified rope spool, with extra slots for reversing and some mechanism with a lever and two detents to move the baseplate between normal and reversed timing. Then I'd probably pay good money to see a video of you going from ahead to astern in a close quarters situation.
(Its the re-wrapping the rope bit when you have to wrap it the wrong way against all your years of developed instinct while your bow is getting ever closer to T-boning the expensive gin palace that would be the best. Might need two addditional camera angles - one for the look on your face, the other for the gin palace's owner in his deck chair with his pink gin in hand!)
-
Charles UK
Hugo I see no reason why you couldn't change the direction of rotation.
The bearings won't notice, the point's might as they would be leading rather than dragging, shouldn't bother them.
It will make the transom bracket very happy not to have that smelly, oily, rattley old Seagull pushing it into the stern of the boat.
The lower unit & prop, if not restrained should throughly enjoy trying to pull themselves out of the water & all the thrust loads being directed through the crown wheel into the pinion & then into the pinion bearing, should promote some interesting wear patterns & give the prop shaft thrust washer some well deserved rest.. It will be interesting to see how the prop retaining split pin copes with the added responseability of having to keep the prop from it's escape bid.
Only clutched lower units will have major problems, if prevented from pulling away from the stern & the prop escaping the prop shaft, the prop will pull it's self away from the gearbox disengaging the drive dog on a continual basis, this should almost make the lower unit play a tune though not for long.
The lower unit best suited to this task would be the 3.1 to 1 FNR box as it has designed in reverse thrust ability & it would be most amusing to have foward where reverse currently resides & visa versa.
But us residents in the Northern Hemisphere are forced to ask ourselves the question, WHY? maybe it's an Aussie thing.
Let us know how you get on.
Good luck
The bearings won't notice, the point's might as they would be leading rather than dragging, shouldn't bother them.
It will make the transom bracket very happy not to have that smelly, oily, rattley old Seagull pushing it into the stern of the boat.
The lower unit & prop, if not restrained should throughly enjoy trying to pull themselves out of the water & all the thrust loads being directed through the crown wheel into the pinion & then into the pinion bearing, should promote some interesting wear patterns & give the prop shaft thrust washer some well deserved rest.. It will be interesting to see how the prop retaining split pin copes with the added responseability of having to keep the prop from it's escape bid.
Only clutched lower units will have major problems, if prevented from pulling away from the stern & the prop escaping the prop shaft, the prop will pull it's self away from the gearbox disengaging the drive dog on a continual basis, this should almost make the lower unit play a tune though not for long.
The lower unit best suited to this task would be the 3.1 to 1 FNR box as it has designed in reverse thrust ability & it would be most amusing to have foward where reverse currently resides & visa versa.
But us residents in the Northern Hemisphere are forced to ask ourselves the question, WHY? maybe it's an Aussie thing.
Let us know how you get on.
Good luck
-
Charles UK
Ian
We have to remember that it was from the southern hemisphere that the twin carb LLS & the twin cylinder 40 appeared.
Our fellow site members from down there think so far out of the box, someone converted it into a dunny!
Though I'm forced to confess it's the Kiwis that are farthest from the box.
Take a trip down there, to meet some of the Seagull crowd, the welcome you will receive & the adventures they organise will most certainly put us northern dwellers to shame, & the beer's cold!
We have to remember that it was from the southern hemisphere that the twin carb LLS & the twin cylinder 40 appeared.
Our fellow site members from down there think so far out of the box, someone converted it into a dunny!
Though I'm forced to confess it's the Kiwis that are farthest from the box.
Take a trip down there, to meet some of the Seagull crowd, the welcome you will receive & the adventures they organise will most certainly put us northern dwellers to shame, & the beer's cold!
Don't worry, I don't have roos in my top paddock.... they have all been accounted for. As mentioned before I wish to make a paddle wheeler with each sidemounted paddle belt driven from its own seagull and thought for asthetics it would be better if both sides looked the same hence the need for one backwards rotating gull. I seem to recall that old Ransom mowers used a slip belt as a clutch system. How a belt would grip in water will be an amusing experiment but no doubt a solution can be found. Pulley's instead of props.
Cheers Hugo.
Cheers Hugo.
Hi,
two strokes don't have valves and, so as long as it's a basic design, they don't mind which way they run.
My dad used to drive his BSA motor bike backwards down the high street on his way home from the pub for a laugh in the good old days!
My sisters Yanmar 1gm10 inboard often fires up backwards and fills everything with smoke! So not so good with a diesel!
regards
Phil
two strokes don't have valves and, so as long as it's a basic design, they don't mind which way they run.
My dad used to drive his BSA motor bike backwards down the high street on his way home from the pub for a laugh in the good old days!
My sisters Yanmar 1gm10 inboard often fires up backwards and fills everything with smoke! So not so good with a diesel!
regards
Phil