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40+ reversing

Posted: Tue Dec 20, 2011 5:33 pm
by Sandro_Picchio
Hi,
I own a Fourty Plus of 1963, S.N. SJP 894 E3.
I used it on a 12 feet sailing dinghy in the first place and later on a Drascombe Dabber (15'6" open yawl).

The Seagull is by far the best outboard for reliability, simplicity, non corrosion, dimensions, weight and,last but not least, character. It is non plus ultra for sea or lake "long" range cruising but, for some inland water use, like maneuvering and/or "playing large yacht" in tight spots, the ability of neutral and reversing is needed. Oars, that I normally use for maneuvering, are too widespread in some instances, e.g. traffic in the narrow canals in downtown Venice.
So in 1984 I bought a Johnson 4 hp that has neutral clutch and can swing 360° and since the Seagull is only seldom used.

The Johnson is almost OK; I even made some modifications to it for better and safer handling. (See "Practical Boat Owner" May 2010 and August 2010 issues) but I am a fan of Seagull and would like very much to restore it in its position of the standard engine on my boat. Moreover it is more suitable to a traditional boat like my Drascombe, albeit on the edge of needed power.

I think that some later Fourty plus had the neutral feature. Is it possible, changing a few parts, to add it to the 1963 model?

Reversing is a much harder matter.

Many years ago I saw a Seagull Forty with a flange encompassing both tubes, that could be swinged 360°. I wonder if this solution would fit the narrow outboard well of my boat.

I thought to a shaped spoiler to be lowered abaft the propellor, turning the water flow forward, same principle as jet aeroplanes braking after landing.

I wonder if someone made or adapted a gearbox with two propshaft gears, really reversing the rotation direction.

I wonder if there is a variable pitch propellor so small. This woud give some other bonuses, as no need for neutral and ability of matching different conditions like speeding on flat water or slowly beating with a loaded boat against wind and waves. But this would also mean say good by to simplicity and reliability.

All ideas and suggestions will be the welcome and please don't consider me quite crazy. Might be just a little.

Thanks in advance,

Sandro

Re: 40+ reversing

Posted: Tue Dec 20, 2011 6:14 pm
by Niander101
Some seagulls have reverse
not sure about small ones though?

Re: 40+ reversing

Posted: Tue Dec 20, 2011 6:34 pm
by charlesp
None of the forty series ever had reverse. In fact the great majority didn't have neutral either.

The 'reversing mechanism' referred to above is most probably a version of the 'Rotagull', a clunky cast alloy contraption that fitted around the two vertical tubes offering a means of rotating the whole motor around 360 degrees. These things turn up on Ebay occasionally. I have never used one. There were other similar devices, all very short lived.

I don't think anyone has converted a forty to Forwrd/Neutral/Reverse, if they have then I have not heard of it.

I have seen a folding propellor developed for the Sail Drive Seagull, but it was not variable in terms of being controlled from the cockpit; it just folded up when not under power.

I am not aware of any 'reverse thrust' add-ons, but you're not th first to mention the idea.

I have heard of a gentleman in Poole who fixed a manual baseplate fixing screw - ie one with a large wingnut, which allowed him to reposition the magneto baseplate in such a manner that he could start the motor backwards. This effectively gave him reverse for a few moments - usually only a few seconds is required to reverse out from a pontoon. The magneto would be shifted round to the correct position for forward running after the maneouvre and off he would go. He was aware that while running in reverse there was no coolant water being pumped round. I have never tried this out myself, but one day when I have a forty in the tank I might just 'have a go' out of curiosity...

Re: 40+ reversing

Posted: Tue Dec 20, 2011 7:06 pm
by Niander101
I have heard of a gentleman in Poole who fixed a manual baseplate fixing screw - ie one with a large wingnut, which allowed him to reposition the magneto baseplate in such a manner that he could start the motor backwards.

Like that idea!

Re: 40+ reversing = progress backwards

Posted: Tue Dec 20, 2011 8:10 pm
by Robin Anderson
Hi Sandro,
The once marketed "Rotagull" contraption which allowed 360 degrees turning was not a commercial or engineering success and more trouble than it was worth I imagine. Incidentally I found the forward-neutral -reverse gear arrangement on my 6 hp Kingfisher to be unreliable - it was forever seizing up and had to be re-built constantly, so ......
Buy a paddle!

Robin
Pleiades of Birdham
MXWQ5

Re: 40+ reversing

Posted: Tue Dec 20, 2011 8:11 pm
by Charles uk
It's not rocket science to make a seagull run backwards.

You would have to make a device that would enable you to move the timing 46 degrees to what would be 23 degrees before TDC when it's rotating in reverse, but it would have to lock into the exact location without the risk of setting the timing in the wrong place & raise starting problems.

I'm not sure that it wouldn't pump water in reverse, perhaps not quite as much.

The only other problem I can think of, would be that if you could stop the motor pulling itself out of the water, the crown wheel would be loading up itself & the pinion, perhaps not the best situation.

Re: 40+ reversing

Posted: Tue Dec 20, 2011 10:32 pm
by Hugz
Wouldn't the shear spring unwind (or distort)if running backwards?

Re: 40+ reversing

Posted: Tue Dec 20, 2011 11:19 pm
by Niander101
Someone wanna try it and whack it on youtube...i dont have any small gulls

Re: 40+ reversing

Posted: Tue Dec 20, 2011 11:52 pm
by Charles uk
Good point Hugo I hadn't thought of that!

I don't think it's going to be me doing it for your entertainment Niander, I never use reverse on my motors that are fitted with it, putting more than 10 minutes work into an exercise like this with no obvious benefits, seems like a waste of time.

All you've got to do is

Machine the rope sheave so you can use in both directions,
Modify base plate so it can rotate & lock & have movement limit stops,
Obtain & fit an FNR transom bracket & the rubber collar on the drive shaft tube,
& if you have spring problems fit a 170 spring & carrier inside the prop hub,
If you have pumping problems, machine water pumphousing so it pumps in both directions,
& if the gears load up fit a hardened steel spacer inside gear box to take the thrust.

£100 for a model 90 is starting to look like a bargain!

Sorry to ruin your dream.

Re: 40+ reversing

Posted: Wed Dec 21, 2011 12:20 am
by Hugz
That's why I like the Woo Hoo Anzani Pilot with 360 degree rotation. Light too.

Re: 40+ reversing

Posted: Wed Dec 21, 2011 1:00 am
by electrosys
Sandro Picchio wrote:[...] I thought to a shaped spoiler to be lowered abaft the propellor, turning the water flow forward, same principle as jet aeroplanes braking after landing. [...]
You might to take a look at US Patent #1467521 , which is an outboard adaptation of the classic Kitchen rudder. There's no reason why you couldn't fit a reversing cowl instead.

If it's of interest, I've designed a reversing mechanism which could be applied to all Seagulls, which involves the making of a custom transom pad, which can be reversed by a 'swinging-gate' mechanism (rather than rotation as with the Rotagull), thus reversing it's position along with any outboard clamped to it. Because of the weight involved with the larger Seagulls, the hinge pin will need to be substantial. But I won't be giving any further details until I've actually made one and ironed out any bugs. Hope to have a prototype fabricated by early spring, when I hope my health problems will be resolved.

Re: 40+ reversing

Posted: Wed Dec 21, 2011 1:17 am
by Charles uk
That's 2 more members for the Mad Professors Club, I won't feel so alone now.
First the electric start petrol head & now you, welcome!

Re: 40+ reversing

Posted: Wed Dec 21, 2011 9:55 am
by The Tinker
:twisted: :twisted: You would not want to try and start a seagull in reverse. Had one backfire and start backwards. Grabbed the starter rope out of my hand and proceeded to whip the back of my arms. Got eleven good welts on the back of my arms before I could get out of the way, and they really hurt and took ages to heal. :evil: :evil:

Re: 40+ reversing

Posted: Wed Dec 21, 2011 2:01 pm
by electrosys
Thought you might enjoy seeing some ideas that were around in the 1920's. The Alexander patent has much the same kind of control mechanism that was fitted to Kitchen rudders of that period, whereas in the McNab patent, neutral and reverse are engaged by lifting the tiller upwards. Might give you a few ideas ?

Re: 40+ reversing

Posted: Wed Dec 21, 2011 5:40 pm
by Sandro_Picchio
Hi everybody,

Charlesp, the swinging flange that I saw was home made, wooden, in two halves. I can't remember any more details.
Reversing the 2 stroke motor direction appeared in this forum, together with the timing issue; as reversing is mostly used in a hurry, one must have absolute trust in the instant starting of the motor; it can be had just with a Seagull.
I do not think that starting the motor CCW would be any more dangerous than CW. The string would be winded the other way and the new slot accordingly. A backfire would have the same effects in both ways.
B. t. w. In Genova I saw a retired tugboat with a huge 2 stroke Diesel that used this way for reversing.

I had not thought at the reversed thrust on the prop shaft, not foreseen in the gearbox design.
I agree with Charles uk about the cooling water delivery. Of course some way of locking the tilting when in reverse must be devised.

I think that the shear spring would distort only when hitting some obstacle, not in normal driving, but this is only my guess.

Robin, I already have on board a pair of sweeps about 3 metre long, I don't need a paddle.

Electrosys, very interesting drawings. Much better than my first idea - a spoiler sliding vertically instead of swinging.


I feel honoured by the membership in the Mad Professors Club.

I thank everybody for information and advising. As things turned out, probably it is unlike that I 'll do any practical action, but you never know. In case I'll let you know.

Sandro