Which Tohatsu outboard 8, 9.8 and saildrive or not ?

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markpageant

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Previous post lead to some more reserach on an outboard as main engine on my 23ft Westerly Pageant. Tohatsu seem to do a good range. There is about 50quid difference between the 8 and 9.8 (same basic engine and therefore weight). The sail drive vsn has a 'thrust' prop and charging for battery. I assume but am unsure that the sail drive has a longer shaft. For a price difference of 50 quid I cant think of a reason not to buy the 9.8. I'd welcome advice on the 8 or 9.8 and on saildrive or not ? Any views ?
 
I can just feel the sighs coming when I ask this next one, but I'm new to outboards. If one steers with the outboard tiller on a tender should does that mean that i should fix my rudder centrally and steer with the outboard tiller when motoring for greater manouverability ?
 
Would check the recommended engine for the tender .. Sail drive has charging capability for battery .. Different propellor gives more thrust but less speed .. Would not bother with a rudder .. How are you going to cope with both .. If you do use both then fix the outboard .. Usually a screw to set position and then use the rudder ..
 
You will find the high thrust prop on the saildrive will give far better performance with a displacement hull. The standard prop has a higher pitch which will give a higher speed on a lighter boat, where the lower pitched high thrust prop will give more power at slower speeds. It is a bit like driving a car in the right gear. Not sure about the shaft length, with the smaller 4 or 5hp engines the saildrive engines have the same length shaft as the long shaft engines.

The charging coil output is usually so low powered that the engine needs to be running for so long to put much back in the battery. It will however run a light or two.
 
I cant comment on the engines as I havent used either but you definitely want the saildrive prop. It gives you much more slow speed power for manouvering .An ordinary prop will give you very little stopping power when you go astern to slowdown or stop.

The power output on our Honda 8 keeps the battery topped up provided we are frugal with lights etc and obviously we dont have a fridge or any other large gobblers of electricity.
 
Not sure if this is relevant to your intended use but I have a 9.8 Tohatsu 2 stroke 'sail drive', which I bought new in 2006.

Although it's light (29kgs), starts and runs well I've never been all that impressed by its ability to 'sail drive'!

What I mean by that is, although I've tried 4 different props (from 5.25 inch pitch to 8.5) it doesn't seem to transmit 8-9 horses into decent thrust to move 1800 kgs of boat. It's either screaming and frothing the water like an egg whisk (5.25 inch pitch) or starting a half reasonable job before going cavitation crazy (8.5 inch).

I've settled on the 7.5 inch pitch as an unhappy compromise. I was told by a marine engineer (after I bought it) that Tohatsu engines (2 strokes at least) weren't really developed with powering yachts / heavier craft in mind, and so aren't really the best tool for the job.

I talked to Tohatsu UK about this and they sent me (via the local dealer) a 'modified' prop - which is the (7.5 in) one currently fitted.

Part of the problem is the leg of the engine simply hasn't got the space to swing a large enough diameter prop. I'm sorely tempted to sell it / trade it in (accompanied by its three spare props) and buy what I probably should have in first place, but didn't to save some money - Yamaha High Thrust 9.9.

I'm not sure that things are all that different with Tohatsu 4 stroke engines either. A guy who sails the same boat as me has one and complains about it being noisy and requiring lots of revs to keep the boat moving.

Not really having a go at Tohatsu here, it's just my experience with the 9.8. I should say I also have a 3.5 Tohatsu (2 stroke) that zips the dinghy along nicely.
 
I don't know about the larger Tohatsus, but I bought a 5HP longshaft saildrive last year to engine my 20 foot Vivacity sailing cruiser & have found it, above all, reliable: to me that is the most important aspect of any marine engine. It also sells at a good price (I got mine at boat show discount). I was constrained by budget (aren't we all) from contemplating the larger versions, although the weight of the engine also came into it: these 4 strokes aren't as easy to move around as the old 2 strokes. But I guess I would always go for extra power, so long as the prop is right: apart from anything else, you would get better fuel economy. On my version the prop is supposedly designed to push along a dislacement hull. I am based in Axmouth harbour, which has a rather notorious reputation for a white-knuckle entry/exit, and have found the engine adequate. Charging my battery up when running the engine is also useful. I've been told that the Tohatsus are essentially the same as the Mariners, although I don't know how true this is. If I was a rich man I would probably have gone for a Honda!
 
Think you have an inboard rudder, in which case you will not get much help from water flow over the rudder from the engine. Normal to mount the outboard on a swing down bracket centrally on the tramsom. You will need to get the height right so that the leg is immersed correctly. You can then also use it for steering with the steering friction slacked off a bit. Useful for going in reverse. However you will find it tricky leaning over the back, bending down, trying to see where you are going etc. You will also find that being well behind the centre of pitch of the boat you will sometimes have the prop out of the water in choppy seas.

This is the sort of compromises you have to deal with when you use an outboard on a boat that really needs an inboard. However, many people do because the value of smaller old boats does not justify the cost of a new inboard.
 
[ QUOTE ]
The charging coil output is usually so low powered that the engine needs to be running for so long to put much back in the battery. It will however run a light or two.

[/ QUOTE ]

The rated output is 6 Amps. If it's anything like my Yamaha, which also has a rated output of 6 Amps, it's more than a charging coil, it's an altenator with a regulated and rectified output suitable for direct connection to a battery. It runs the whole boat's electrics, not just a light or two.
 
Not a silly question. Steer normally with the boats rudder.
However, when you want to practice intricate manoeuvres ( like reversing into a tight marina berthy across wind and tide), you might like to try leaving the boats tiller 'locked' straight ahead using the autopilot but turned off, and then squat at the back of the boat and play the throttle/outboard tiller together. You will soon be able to make that boat walk sideways or spin in less than its own length. If you go aground, turn the outboard tiller and use the motors thrust to spin you off the mudbank and back towards deeper water!

As said you definitely want the larger motor with full bladed sail propellor.

It is quite useful to have two remote petrol tanks too, then you can lug one ashore and fill up with 'normal' priced petrol and monitor your consumption better/quickly change over tanks at sea.
 
I assume this engine will be mounted on the transom

If so I would get an Ultra-long shaft if you can. Tohatsu are one of the few who do them but I am not sure if they do them for the 8/10hp range.

If you are bouncing aboutin a seaway and ultra-long shaft keeps the prop in the water more of the time.
 
[ QUOTE ]
The rated output is 6 Amps. If it's anything like my Yamaha, which also has a rated output of 6 Amps, it's more than a charging coil, it's an altenator with a regulated and rectified output suitable for direct connection to a battery. It runs the whole boat's electrics, not just a light or two.

[/ QUOTE ] I agree - I have the 10amp Mariner 9.9hp and it does produce 10amps. Things have moved on from the charging coil days but most people haven't realised.
 
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