I am thinking of moving my 6hp 4stroke from the transom into a well. I have looked at the relevant posts on here but have not seen any mention of the outboard length. Can someone please advise.
Also, does anyone know whether the moulding shown in the technical manual can still be obtained?
Many thanks,
Andrew Turner, Seal 22/28


A Turner

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Hi
I used to own Tulena, a 22 with outboard in a well.
I had a few engines all of which were long shaft and fitted with yacht props.
I think you can use a short shaft if you set the engine low enough but in rough conditions the prop will come out of the water a lot.
It happened rarely, but did happen,even with the long shaft.
I have not heard of the moulding for a long time but it may still be available. Tulena's well was formed by sectioning off the sides of the aft locker with glassed over plywood and the front of the locker cut down and reinforced, again with glassed in plywood.
This was done by a previous owner, but looked OK and worked well.
Tulena still lives in Chichester Harbour, the owners are members.

Good luck
Philip Linsell

Philip, thanks for the information. Very useful. My outboard is a longshaft so would be ok. This sounds like a winter project.
Andrew


A Turner

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Moonspinner has a long shaft Tohatsu 5hp two-stroke outboard and rarely if ever does the prop leave the water under way. A short shaft motor would work ok I think but the prop could surface in heavier weather. O

ne thing to consider is the by-pass exhaust on the motor leg - which will choke up the motor well and 'stink out' the cockpit (and cabin with a following wind) if not addressed. I made up a GRP manifold for the exhaust bypass (it doesn't get hot really) and the exit spigot takes a rubber hose fitting (just pulls off to ship the motor) and exits over the transom - well tested, works a treat and the exhaust is out of the boat. Soon to fit a through-hull fitting.

Some people have done it the other way and piped a fresh air supply to the motor from outside the engine well, all this assumes the cover is on... A fresh air supply would stop the engine choking on exhaust fumes but not the crew! Its worse with a two-stroke, the smoke anyhow, but the fumes and Co2 output will also be given out by a four-stroke...

Greg...
Seal 22 - Moonspinner

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I can totally endorse what Greg Faux has posted about the need to make up an exhaust by pass - this is absolutely essential for the smooth running of any outboard engine enclosed in a well, and also for the well being of the crew!

And Philip Linsell briefly alluded to "yacht props" - there are two key factors to maintaining drive, and hence speed, in rough waters - the first is to use a Longshaft outboard [which you already have] and the second is to fit the largest diameter, smallest pitch, 3 bladed propellor that you can buy for whatever make of engine you have. Expect it to have large area blades, and perhaps to be described as a sail boat or work boat prop If you have through-hub exhaust, you need a sail boat prop with deflectors that reverse the direction of the exhaust when you go astern, in order that the exhaust gases do not break up the water flow to the blades and destroy your astern thrust.
Many outboard propellors are interchangeable between brands, so don't be afraid to ask other brand dealers if yours doesn't seem to have what you need.
When my Seal 22 was in commission, I used to run a 7.5hp two-stroke longshaft fitted with a 9.25" x 6.5" three bladed prop, which easily drove the boat at maximum hull speed, and made it very manoeuvrable.



Geoff Sheddick
Parker 27/146 "Stroller'

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I can endorse that it is possible to destroy the astern thrust. I changed my initial propellor to a higher pitch because the original was causing the engine to overrev ( an 8hp Tohatsu 2 cylinder 2 stroke). However the new propellor, although excellent in forward (lower revs better top speed) has trouble in reverse producing enough thrust. The exhaust is through the propellor which isn't helping, but since the reverse had originally been adequate , I had put it down to the camber in the blades not working well in reverse. The camber on the new propellor is much larger than that on the old.

http://freespace.virgin....james.hamilton/forum.jpg 

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Oops.. I should have mentioned Moonspinner's motor has a saildrive prop.... It is much better than the standard prop which has to high a pitch for a displacement hull. Don't know if others will agree or not but the saildrive prop with its three large blades also gives much more thrust going astern and it's worth fitting one for this alone - especially if you need to manoevre in marina's etc...

Greg...
Seal 22 - Moonspinner

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