Outboard for a displacement hull

[Knut Sand]

This is also pretty much why I keep asking for dimensions for a "bigfoot" engine...

You have one here:
http://www.hinterlandmarine.com.au/o...t_4-Stroke.php

They are superb for driving heavier hulls, geared differently (making the gearbox a little bigger, but at deplacement speeds, a thing like that doesn't matter that much). Handles bigger propellers with more ease than the standard version of the same engine.

Also; the chock to the gear, hammering it in reverse is something it is better designed for, as putting a heavy propeller on a standard gearbox may cause more stress than the gearbox likes to handle.

[Knut Sand]

Originally Posted by RockLaker

I'm from the world of planing hulls and I find 10 hp on a boat that huge interesting.

Ok, then the first thing you will have to realize: Deplacement speed is slow. dead slow, and many find it dull.

But the engines needed is smaller, cheaper, and the money spent for fuel for time on the water is way less than for a boat with a planing speed, running on planing speed. It'll help saving our fuel reserves if more deplacement boats were built. But the theme of our time, is bigger, better, faster, more...

Also, to remember, when your back or reached your destination, the journey is over, on a deplacement boat, the journey takes longer... Just a question of altering your mental settings....

Look like a nice boat, what aboat just putting the engine on the transom, instead of building a well?

[RockLaker]

Whoops, never noticed the link for some reason. Read all the posts though. Thanks.

Sometimes I like to go fast, but I've always loved the idea of trawler-type cruising on a bigger boat for a long time. A small, dependable motor running for hours on end while putting along in relaxed comfort really turns my crank. It's almost like I was an offshore fisherman in a past life.

Now that I've seen the boat and realize what will be done with it, I'd rather the smallest motor that would push the boat at displacement speed at about 1/3 to 1/2 throttle. Running a 10 at full throttle would be far louder, harder on fuel, and wearing out quicker than a 20 at 1/2 throttle. So I guess if 4hp is needed, as mentioned, then I think I'd go for a 15 and give it a life of light-duty work, but will run fast enough to keep the carb clean. Then make that motor a Honda 4-stroke and it'll last 100 years.



Allan, great job on the boat!





LC.

[Allan]

I've been busy most of this summer trying to finish this boat and it looks like I'll get it into the water by the end of this month at least for a trial run. We are already hitting freezing temp. in the evening here. I ended up getting a demo Honda 15hp long shaft with electric start and remote control for the price of a similar 9.9hp. I'm putting a high thrust prop on this motor as well and have installed a 20 gal. fuel tank below the floor as well as carrying a 10 gal. portable tank so I'm hoping for a range of several hundred miles which should take me most places I'm interested in exploring. I'll post some pictures of the finished boat at a later date. Actually had a chance of going on a high speed cat this summer and must admit it was the most unenjoyable means of travel on the water I've ever experienced, give me displacement hull speed anytime.

[Guest625101138]

I am looking forward to the photos and feedback from first trip.

I would be surprised if you do not find the Honda more than adequate. Electric start and remote control should give it a big boat feel. Nothing more dinghy like than having to run aft to pull a string to get the motor going.

Rick W

[Riverrat1969]

Allan, that's a nice looking conversion! I am pushing a 24 foot Carolina Skiff with a 9.9 HP four stroke Evinrude (Suzuki in disguise). I got a wider blade, shallow pitch prop, and with six people, two large dogs, and lots of gear, we do 3 statute miles per hour (GPS) at fast idle.........top end 8-1/2 MPH.

I used this Evinrude, because I already had it, but if this outboard ever wears out, I would get the 9.9 HP four stroke Yamaha high thrust outboard to replace it.

Yamaha came out with that engine many years ago, to push 25-30 foot sailboats.........way before most manufacturers started offering four stroke outboards. [color="Red"]Tried and proven for a long time, the Yamaha high thrust has lower gears and a larger prop, than a typical outboard.[COLOR="red

[Allan]

Finally got the boat finished enough to try it out this weekend. The Honda outboard pushes the boat along at a nice leisurely 5 to 6 mph at half throttle and is so quiet that you can have a conversation without having to raise your voice. There is still some work to finish on the boat but nothing major. It should work out quite well as camping boat for us and on the lakes and large rivers here as we can sleep on the v-berth up forward and close off the cockpit area with the canopy when the weather gets too wet Plus there is lots of storage space onboard for gear.
You can see pictures of the boat at
http://www.watsonriverdesign.com/Boat04.htm

[Guest625101138]

Allan
Great to see you are finally on the water. The job looks good.

The modern motor is a bit out of place in an old style displacement boat but I bet there are many people wishing they could get your fuel economy. I think we will see a lot more leisure boats like this in the future. It is time on the water that counts not the speed you travel. Have you any idea what fuel economy you are achieving?

I imaging the boat enjoys the reduction in weight. I expect will be a touch more tender now but more than adequate for river and lake use.

Have you had a chance to open the throttle to see what top speed is. No doubt a lot of wave making at full throttle.

Would be nice to see a photo of the trim under way. Is there any risk of the prop grabbing air when cresting a decent wave?

Rick W

[Allan]

When I took the boat out for it's trial run I just used a day tank hooked up to the engine. I'm now in the process of hooking up the the below deck fuel tank that is located in the bow of the boat and I'm now starting to wonder if the fuel pump on the Honda 15hp will be adequate to draw fuel from the tank to the motor. I asked the local dealer and they couldn't give me an answer. The tank is located 15 ft away and 2 ft below the motor.

[Guest625101138]

I would be surprised and very disappointed with the Honda if it could not get fuel easily under those conditions. If you were using extremely thin tubing the distance may make a difference but for something with 1/4" ID or a little larger of typical fuel hose it would cause little resistance.

Rick W.