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sailcanoefan
09-29-2012, 04:21 PM
Hi everyone.

I'm building a 19 ft sailboat from plywood. Estimated weight will be around 800 lbs.

I own a Mercury 3.6 HP outboard motor 2 strokes (around 1995). I wonder if this motor will be good enough for this boat. I want a motor that will be strong enough to power the boat in moderated wind F6, windward and cross wind.

I have run this motor with my sailing canoe (with outriggers) and it goes very well in F5 wind
conditions.

If I have to purchase another motor, I will definitly do.

BTW, Hyfong motor and other Chinese motors, are they good?

Surely I will try my Mercury when I will launch the boat.

Anyone has equivalent in boat and motor size.

Thanks for tips and hints.:confused:

Donn
09-29-2012, 05:53 PM
I can't help you, but I'm looking forward to the discussion of this question:


BTW, Hyfong motor and other Chinese motors, are they good?

http://img.photobucket.com/albums/v54/donnwest/smilies/popcorn.gifhttp://img.photobucket.com/albums/v54/donnwest/smilies/popcorn.gifhttp://img.photobucket.com/albums/v54/donnwest/smilies/popcorn.gif

BBSebens
09-29-2012, 08:36 PM
More detail needed. What kind of boat is it?

If the wind is blowing, shouldn't you be sailing? :ycool:

3.6 hp isnt very much.

sailcanoefan
09-29-2012, 09:40 PM
Yes Mr BBSebens a sailboat usually takes advantage of wind.
That's a good question!!!!!!

But there are times when we can't or don't want to sail like being in rush while going upwind to a point and don't have time to make all those tacks. Or going out (or coming in) a marina or harbor and make sure that the boat doesn't behave like a ball in a pinball machine and hit any boat. There are those delicates situation when a motor is more than useful. And last but not least....there are time when no wind at all.

All sailboats (or almost) usually have a motor (inboard or outboard) to power the craft when needed.

That's why I'm asking: ''How minimum HP this boat needs''?

brucemoffatt
09-29-2012, 10:08 PM
I can't advise directly but for what it's worth, which ain't much, I had a 3.5 HP Evinrude as an auxilary on a 24 foot cruising catamaran and never found a need to upscale it. The cat weighed a fair bit more than 800 lbs. I guess it will depend on what type of hull you'd be pushing, but as it's a sailboat let's assume it will be fair in the water. You might want to consider whether that motor has a leg long enough to stay in the water as you push forward into and across waves in F6 conditions.

Probably you'll only really know when you trial it. I'd do that before committing to upscaling it if I were in your position. If the 3.5 isn't enough then replace it.

Bruce

Woxbox
09-29-2012, 10:51 PM
No harm in trying it out. I think you'll find that's plenty of power. I had an 18', 1200-pound sailboat that I ran with a 4 hp. 2-stroke, and never felt any need for more power. Plus, you want to keep the weight on the transom as low as possible.

Thad Van Gilder
09-30-2012, 09:20 AM
i'd say you need a little seagull.... get rid of that silly mercury....

Stiletto
09-30-2012, 07:25 PM
A mate had a Hartley TS16 with an old 6hp longshaft Evinrude twin , which was light enough to handle and had plenty of power for a boat that size when the chop was up.

As others have said, I think the best thing to do is finish the boat and try your current engine out, then decide if you need more power.

The Chinese engines havent gained wide acceptance here.

beernd
10-01-2012, 12:00 PM
Hello sailcanoefan,

I am no expert in outboards.
But I have just one question : does the outboard have a high trust propeller.
If not could it be outfitted with one?

OK that were two questions.
But I think that makes a big difference.

ataraxia
10-01-2012, 12:27 PM
Why not a Torqeedo (http://www.torqeedo.com) ? No more noise, fumes, leaking petrol and lightweight: a Travel 1003 will push up to 1500 kg

Jamie Orr
10-01-2012, 03:23 PM
I use a 5 hp Honda on my 20' Chebacco - estimated weight 1200#. It will approach hull speed while still not using a lot of gas (35 nm on 1 1/4 gallons or about 5 litres last Thursday), with power in reserve. I've only needed full power once when conditions changed while I was in an awkward place with inexperienced people on board. Even then I could have turned back under sail instead. It's a nice engine, but weighs 60# dry plus a three gallon tank of gas.

Another Chebacco sailor tried a 2 hp Honda, it was slower but did the job however I think a bit more power would be wanted after a few trips. The 4 hp Yamaha (also a four stroke) could be a contender, I used one briefly on another 20 footer and was struck by how quietly it ran.

Good luck in your search,

Jamie

jalmberg
10-01-2012, 04:30 PM
My opinion, after doing 2000 miles in a small boat, some of them quite rough:

If you're just talking about running a quarter mile back to the harbor, before any serious waves kick up, then anything will do. But assuming you are talking about coastal sailing in open water (think nasty, fast, 4-6' waves or worse), the best way to attack F6 wind and wave in a small boat is by motor sailing -- the sails reefed appropriately and the motor running at at most 1/2 speed.

http://www.dngoodchild.com/5101.jpg
(You could go far from home in a little boat like this)

The motor will let you point (much) higher than you could without it (even pointed 45 degrees into the wind, with leeway and surface water drift and waves beating you back, most deeply-reefed small boats are lucky to make 90 degrees into the wind). Keeping the boat moving forward with the engine will drastically cutdown leeway as a percentage of forward motion.

1/2 speed will keep the motor from red-lining when the prop pops out, which it will, constantly. It will also keep the gas consumption down to something reasonable -- important if you must keep going for a long time.

3.6 hp sounds like enough for this kind of motorsailing, assuming the shaft is long enough to keep the prop in the water at least most of the time. I only had a 9.9 on my 8,000 lb boat.

In really restricted waters, like a dredged channel, where there isn't enough room to use the sail, then as long as you can make good to windward you'll get there eventually (this might not be possible if you've got the wind, wave, *and* a 2.3 knot current against you.) I'd keep the mainsail, deeply reefed, ready to go up in a flash, in case the engine packs in. Again, if there are any waves, keep the revs as low as possible so the darn thing doesn't tear itself (and your nerves) to pieces when it pops out of the water.

I actually try to avoid beating into that kind of wind and wave, since IMHO it's the opposite of fun, but sometimes you get caught out. Since I am the weak link in the chain, I try to keep the boat as settled as possible, so I don't get too beat up and tired. This is the most important thing if you have to keep going for many hours (I imagine it would be even more important in a 800 lb boat.) And sometimes the most seaman-like thing to do is to run downwind to the closest protected anchorage and wait it out.

sailcanoefan
10-01-2012, 06:51 PM
I'm not sure of this Beernd, but if I would have to bet I would say no.
Very good question, thank you.

I will ask a dealer....after all a prop is much much cheaper than a motor!!!

sailcanoefan
10-01-2012, 06:53 PM
I like the electric idea, Ataraxia, but for a long run where no recharge is available, I might miss that petrol fumes!!!!!

TR
10-01-2012, 06:53 PM
If you don't have a motor well (forward of the transom) for sure you want a long shaft engine. I have a well but even so with people in the bow the short shaft will pop out of the water.

I've been through a bunch of engines in Ratty, my 20' cat-ketch. The first was a 30pound thrust electric trolling motor, it worked but barely. Then a 2HP Honda, which will work fine but there is no reserve power at all. Towing anything is really iffy, though I have done it. Then we had the big Seagull, 5.5HP or thereabouts, with clutch and huge fan prop, tow anything but the oil slick you leave is slightly dismaying. Then came the 5HP Mercury 4-stroke, actually a Tohatsu motor. This is by far the best, reliable, powerful, smooth, and burns almost no gas. It gave some trouble with oil pressure, due to the fuel pump filling the crankcase with gas, but a replacement pump sorted that. We also have used an 8HP 2-stroke Yamaha, which is a good, but noisy, engine that is currently suffering from a cracked coil problem (runs on only one cylinder). So I currently have four engines, and 3 are spares.

TR
10-01-2012, 07:00 PM
Oh and Peter Gron built a 23' Arctic Tern here on the island.......http://members.shaw.ca/pgron/ArcticTern.htm (http://members.shaw.ca/pgron/ArcticTern.htm)

He has a Torqeedo auxiliary which he is happy with but it has very limited range. Crossing the strait he substitutes a small Seagull which is fine.

sailcanoefan
10-01-2012, 07:02 PM
Thanks Jalmberg, that's a good contribution from you, an experienced sailor.

My motor has a short shaft, but I beleive I can use a swivel bracket holder after determining the appropriate height at transom.

One fellowmember suggested me to check about the propeller trust, maybe a different pitch would make a difference.

The best is to wait until the boat is ready to be launched and try that 3.6 HP Mercury.

Like they say:''Wait and see''

sailcanoefan
10-01-2012, 07:03 PM
Thank you all for your support and hints I appreciate very much.

BBSebens
10-01-2012, 08:04 PM
Yes Mr BBSebens a sailboat usually takes advantage of wind.
That's a good question!!!!!!

But there are times when we can't or don't want to sail like being in rush while going upwind to a point and don't have time to make all those tacks. Or going out (or coming in) a marina or harbor and make sure that the boat doesn't behave like a ball in a pinball machine and hit any boat. There are those delicates situation when a motor is more than useful. And last but not least....there are time when no wind at all.

All sailboats (or almost) usually have a motor (inboard or outboard) to power the craft when needed.

That's why I'm asking: ''How minimum HP this boat needs''?


I know. I was mostly joking.

I had a San Juan 21 with a fixed keel. It weighed about 1800 lbs. I used a 6hp 2 stroke, because its what I had. Seemed to be enough.

jalmberg
10-01-2012, 10:40 PM
Thanks Jalmberg, that's a good contribution from you, an experienced sailor.

My motor has a short shaft, but I beleive I can use a swivel bracket holder after determining the appropriate height at transom.

One fellowmember suggested me to check about the propeller trust, maybe a different pitch would make a difference.

The best is to wait until the boat is ready to be launched and try that 3.6 HP Mercury.

Like they say:''Wait and see''

Theres more to high thrust than the prop. You need the higher gear ratio. No doubt a high thrust, long shaft motor woul be ideal, but not cheap. I'd try what you have, and see how it works.

sailcanoefan
10-02-2012, 09:59 AM
I tough this was a joke too!!!!

ataraxia
10-02-2012, 11:05 AM
Just take a spare battery (only 3,8 kg or 8 lb) with you or a solar panel (http://www.torqeedo.com/us/electric-outboards/solar-charger-45-wfor-ultralight-and-travel/speed-range-run-time)

sailcanoefan
10-02-2012, 08:27 PM
Thanks everybody for tips and hints.
My conclusion is that it's wise to try actual outboard and see how it's behaving.

I close this thread now.