Inboard vs Inboard

[hrt1009]

This topic has surely been discussed many times but, I cannot find a reference.

During previous ownership of keel boats I was usually able to get them into and out of a marina pen without drawing too much attention to myself. However, each one was fitted with a centre line diesel.

I am now looking at buying a TH which has an 8 HP OB mounted in a well, and I cannot see this will be a good thing when it comes to maneuvering. For example, I don't think there will be much prop wash effect to assist turning, while I suspect operations in reverse may be a haphazard affair.

If people with first hand experience of the two drive systems can give me some guidance, I would be most grateful.

[Shaun]

Welcome to the Top Hat website.

If the OB motor can swivel in the well(which many can, even with a minor adjustment), I see that as a huge advantage to maneuverability, with both the rudder and the propeller controllerable.
From my experience inboards are more convienient if you need to motor large distances over long periods of time, & rough bar crossings. Outboards are more than adequate for on & off the moorings, onto wharfs, into marinas etc.
cheers

[Troppo]

Hi hrt1009, my boat, Windchaser has a 18 hp Tohatsu 2 stroke outboard courtesy of the previous owner. While I think 10 hp would be enough horses, that is what came with the boat.

I can only turn the motor a few degrees in the well. Does not sound like much but at cruising speed I sometimes notice a bit too much pressure one way or another on the tiller which goes when I turn the motor a touch.

I have limited experience with reversing. My previous boat had a diesel and was a pig to reverse. I think Windchaser with the OB is a little easier to reverse primarily because I can give a fast burst of the throttle and it quickly moves a mass of water over the rudder. The fast bursts work for me to get it started then a steady throttle takes her back no problems.

Don't know if any prop wash effects.

I never intended to use my 2 stroke motor as much as I have no other option if I need to motor so I have used it a lot. For example, I used the motor more than the sails coming up from the Gold Coast where I bought her to Rockhampton where she is moored. And, I just did a 70 nm round trip down river and back on the motor. Under the following conditions, I have never had the motor cavitate or perform anything but superbly. Crossed the Wide Bay Bar through 3m+ breaking waves, some of which I had to turn with and surf until it passed then turn back to the track. A few times on the river here with wind-against-tide I have been in 1m - 2 m very rough short chop where the bow get buried up to the toerail and the boat is slewing from side to side from the waves. Never a problem with the motor.

My motor is a bit noisier than I like, but okay as I run at half throttle or less. It also uses more fuel than a diesel but then when I went to get it serviced I simply took it home with me. The only time it has concerned me was after I had not run it for two months (I like to run it at least once a month) I could not start it but the next day I started it. Oil residue in carby from sitting too long.

Have an electric start but often start it manually and very easy.

In general I like diesel motors and not two-stroke petrol motors however I have been very pleased with my outboard and while my situation with the distances motored on the river better suited for a diesel, the outboard has given sterling service and has other advantages I am very pleased with. In fact, if I had the choice, I think I would go for a 4 stroke outboard so I can keep the extra space in the cabin under the cockpit and hopefully have lower noise and less fuel consumption.

troppo

[Ianb]

Troppo, How do you store your motor? I have seen some lifted up out of the water and supported on a stand, with some device to lower back down. Pretty sure a 9.9 hp 4 stroke or even 2 stroke would be too heavy for me to manoever into the cabin. Sea Lady has hers permanently in the water, and I was surprised (from what I could see through the water,) that there was very little fouling. However, on her mooring, there was quite a lot of pitching movement, and I was thinking that it could be beneficial to stop growth build-up.

[Miker]

Hrt, in my experience, the outboard is very useful in manouvering at close quarters. Mine is actually on the back of the transom on a lifting bracket. This was courtesy of the previous owner, who bought an 8hp 4 stroke Tohatsu. The head of the outboard was too big for the existing well, so instead of making the well larger, he just stuck it on the back. It's ugly, but it's quieter over the back, and still reasonably easy to operate the throttle and gearshift. Going ahead, you can turn the boat in its own length. Going astern is a different matter, no Top Hat, diesel or otherwise has ever been good at turning in reverse, but using the outboard tiller, it does turn very well.

I have the same experience as Troppo, with regards to cavitation, although being over the back, it does cavitate a little in steep small chop like the Lake Macquarie bar. Never enough to be a worry though. I've motored from 20 nm south of Lake Macquarie to Careel Bay in Pittwater at an average of 5 1/2 knots in a 2 metre south swell due to lack of wind and used about 5 litres of petrol. So was pretty happy with that. Same with servicing, I unbolted it, took it home, stood it in the shed and did a complete service in an hour.

[hrt1009]

Much obliged for the info provided THers. An OB does not seem to be the bogeyman I thought it would be.

Next question - I'm getting on and lifting an OB in and out of the well does not appeal. If I leave the engine in the water, are there any thoughts as to how much I am going to shorten the life of the leg etc via corrosion?

And, is there anything I can do to lengthen the life of an OB left permanently in the water?

Or, do I grit my teeth and look at replacing the leg etc more often than younger and fitter folks?

[Troppo]

My outboard, being electric start 18 hp, even though a 2 stroke weighs close to 50 kg, which is a considerable amount. I use a 4 pully system although the bottom pulley is actually two in one. So, the rope is tied up on the solar panel frame, goes down through the pulley tied to the motor (roller 1), up to Pulley-1 tied to frame, down to roller 2 and up to Pulley-2 where it comes out and I pull on it. Don't know what the mechanical advantage is but I think I only pull about 15 kg (would be less if pulleys were good ones).

s outboard lifted.jpg (451.52 KiB) Viewed 7363 times

When up, I usually just hold the rope in one hand and slide a board across the seats and lower the motor onto it. Or if one hand not enough, I can cleat the rope off to the side and use both hands on the board.

s outboard 2.jpg (362.36 KiB) Viewed 7363 times

Originally I had all sorts of problems with getting the motor up, especially as it needs to go a bit sideways to come up, but now I find it quick. If I wanted to, I could probably run the rope through the cockpit winch and winch it up. However, I found when I first started lifting the motor up, I needed to put on an extra pulley or two and made it so much easier. One pulley would be the whole weight but four pulleys means about 1/4 the weight on the pulling rope so much easier. Could use even more to gain even better mechanical advantage.

troppo

[storm petrel]

OR you could buy a Top Hat with and inboard diesel. They are cheap as chips at the moment.

Cheers,

Mark
Aruba (Phantom 32)
Ex-Top Hatter

[Troppo]

OR you could buy a Top Hat with and inboard diesel. They are cheap as chips at the moment.

Cheers,

Mark
Aruba (Phantom 32)
Ex-Top Hatter

But those diesel motors weigh 100kg+ so how would you haul that up out of the water when you are not using it?

Oh, wait, you don't need to haul them up.

troppo

[hrt1009]

Thanks Guys. Appreciate the humour in this time of sharemarket dizziness but, could I please have a response to my post about leaving the OB leg in the water?