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Re: Outboard Motors

PostPosted: Fri Jul 18, 2014 3:45 pm
by GreenLake
Your theoretical hull speed is around 5.4, I've clocked non-planing speeds under sail in good conditions to 5.8 or so, and there seems to be a definite "upper bound" there.

Unless you go to a motor that is capable of getting the DS on a plane, you don't want to play in currents like that. As for tides, they do have slack periods :)

Re: Outboard Motors

PostPosted: Fri Jul 18, 2014 4:51 pm
by talbot
Yeah, this is one of those cases where the theoretical limits are irrelevant. We can all plane faster than 5.5 knots given the right wind and point of sail, and a 5hp motor (the max for the DS) could easily plane the boat with the board up. But in practice we try to keep the auxiliary as small as possible, and the whole context here is situations where the sails (for whatever reason) can't do the job.

Re: Outboard Motors

PostPosted: Sat Jul 19, 2014 12:12 am
by GreenLake
I wouldn't directly call the limits irrelevant.

Agreed, the DS can be brought to a plane, but it's a hull that has a definite transition to overcome to get there. (Unlike some modern skiffs where the transition to planing is imperceptible). My own measurements confirm that I would need substantially more power (stronger winds) to get the boat on a plane, in the wind conditions where I measured speeds so far, none of the small fluctuations in trim, course and wind speed were enough to get me over the hump.

Even though the hull speed is not a "hard" limit, it does represents a peak or hunp in the power curve. Keeping your outboard small means that you don't have the power to get over that hump; the hump is higher if the boat is loaded for cruising, or if you bring extra crew.

My conclusion from these facts is that I would not plan on being able to do what the powerboats do, and resign myself to traversing such bars at slack tide. And I would have the benefit of not having a heavy outboard ruin my ability to sail well all the other times.

Otherwise, I'd be sailing a McGregor 26 :)

Re: Outboard Motors

PostPosted: Tue Aug 04, 2015 8:01 pm
by Madcitysal
We have a water-cooled motor for DS II, and are experiencing problems with cooling system getting plugged up with weed debris. Lake Monona in Madison is very shallow in our area with high density of weeds. Looking at Honda 2.3 hp air-cooled. Any advice?

Re: Outboard Motors

PostPosted: Tue Aug 04, 2015 10:12 pm
by TIM WEBB
Even the air cooled Hondas have exhaust cooling ports in the lower unit, so you would need to make sure those stayed clear of debris as well. They also require running the motor in a tub of fresh water after saltwater use.

Re: Outboard Motors

PostPosted: Fri Aug 07, 2015 7:28 pm
by Madcitysal
Tim,
The Honda description for the Air cooled 2,3 hp states that "there is nothing to get clogged." This is contrary to your opinion. Do you feel their description is "suspect?" Thanks posting.php?mode=reply&f=11&t=3522#

Re: Outboard Motors

PostPosted: Fri Aug 07, 2015 8:20 pm
by GreenLake
Tim, are these cooling ports where water is aspirated, or merely exhaust ports where the exhaust exits? In the latter case, there would be no chance for clogging.

The sales literature merely states that there's no water pump to clog; the manual does not mention anything about exhaust cooling, but technically, if there were ports where water is aspirated it would not be a water pump :)

Re: Outboard Motors

PostPosted: Fri Aug 07, 2015 10:14 pm
by TIM WEBB
Madcitysal wrote:Tim,
The Honda description for the Air cooled 2,3 hp states that "there is nothing to get clogged." This is contrary to your opinion. Do you feel their description is "suspect?" Thanks posting.php?mode=reply&f=11&t=3522#

Could be that the 2.3 has a different lower unit than the 2? All I know is that the 2005 2HP model manuals (both owner and shop) make no mention of the exhaust cooling ports, but they both clearly state that the engine should never be run dry (out of water), and should be run in a big bucket of water with the antiventilation plate at least 6" under water. After talking to several different owners of H2 outboards, I am convinced that this is advice well taken. Now, the 2.3 may be an entirely different animal altogether, but something tells me that the lower unit is probably the same on both models. Therefore, if there are "important" ports below the waterline, one would want to keep them clear ...

Re: Outboard Motors

PostPosted: Fri Aug 07, 2015 10:25 pm
by TIM WEBB
GreenLake wrote:Tim, are these cooling ports where water is aspirated, or merely exhaust ports where the exhaust exits? In the latter case, there would be no chance for clogging.

The sales literature merely states that there's no water pump to clog; the manual does not mention anything about exhaust cooling, but technically, if there were ports where water is aspirated it would not be a water pump :)

No, they are small openings on the sides of the lower unit, separate from the exhaust opening on the rear of the lower unit. Correct, there is no impeller, but somehow these cooling ports conduct water around the lower exhaust, need to be kept clear of debris, and need to be flushed out in a freshwater bath after saltwater use. Again, none of this is mentioned in either of the manuals (owner or shop), but I tend to trust those with much more experience than I with a particular piece of equipment! ;-P

Re: Outboard Motors

PostPosted: Sat Aug 08, 2015 1:39 am
by GreenLake
Definitely. Go with the real experience. The need for regular service is one of the reasons I've stuck with trolling motors, despite them being a bit marginal in power. Having an entirely sealed motor has it's advantages 8)

But then, I do have to change the batteries after every use. Seems the best option is to go without motor, whenever you can :)

Re: Outboard Motors

PostPosted: Mon Aug 10, 2015 6:33 pm
by talbot
Greenlake -- you mean "charge" the batteries, don't you?
Question about rinsing a 2hp Honda "after every saltwater use." Does that mean folks who keep their boats in the water at the coast have to bring their motors to shore to clean them after every voyage? I guess I could do that--the 2hp only weighs 27lb. But what about someone sailing an O'Day 23 with a Honda 9.9 auxiliary? Those motors weigh about 100 lbs--surely they hang on the transom for the season.

Is the issue fouling from the water, or salt residue from evaporation? I have been impressed by the thick layer of salt on the underside of the motor where the hot casing get spattered with spray. If you are not in a position to rinse the motor in a tank every day, what about just wiping the whole thing down? (Honda suggests buying their custom fitted logo-emblazoned motor cover, but I'm not sure if that's addressing the same problem.)

Re: Outboard Motors

PostPosted: Mon Aug 10, 2015 9:48 pm
by TIM WEBB
Talbot, I'm not really sure what is expected in those situations, other than to say that motors (with and without impellers) should be run in freshwater after use in saltwater. How this is accomplished I suppose depends on the situation. The H2 is considered a "portable motor", so I guess Honda assumes (rightly or wrongly) that the motor will be removed from the boat and stored after use - at least that's what the literature I have points to. In the case of the larger motors that stay on the transom for the season, I suppose that they are to be flushed out using the "garden hose/earmuff arrangement". For trailered boats this would be done at home after a sail, for boats kept in a slip, you would use the freshwater connection (usually) provided.

The issue as I understand it is that the very same salt residue layer that you are observing on the underside of the cowling is also building up in the various cooling water ducts inside the motor/engine, and the only way to clear them out is with a freshwater rinse. Otherwise you are just asking for blockage and/or corrosion damage in there.

My (used) H2 (luckily) came with a Garelick motor stand, http://www.garelick.com/Outboard-Motor-Carrier#, the 31400 model (something similar could easily be homemade), and after a salt water trip, I just put the motor on the stand, place a big bucket under it, fill it with the hose, and run the motor for about 5 minutes at just above idle (just enough to get the prop turning, but not so fast as to splash all the water out!). I basically run it with the fuel valve off until it quits. This way I know I'm storing it with the carb bowl empty, which I've also been told by several different H2 owners is a good thing to do. But, that's an entirely different discussion altogether ... ;-P

Re: Outboard Motors

PostPosted: Tue Aug 11, 2015 12:06 am
by talbot
Oh, man. Why do I have to keep learning new stuff? Since getting this last boat, I have had to learn . . .
--structural fiberglass repair
--osmotic blister restoration
--VHF radio protocols
--GPS navigation
--12v electrical wiring
--aluminum refinishing and painting
--steel refinishing and painting
--trailer axle replacement and maintenance
--small dog PFD fitting and behavior

Now small engine maintenance. Will it never end? Will I never get to just be an old man, stuck in a rut, telling the same stories over and over? I didn't even want another boat. My wife made me get it. What was she thinking?

Re: Outboard Motors

PostPosted: Tue Aug 11, 2015 5:18 am
by GreenLake
talbot wrote:Greenlake -- you mean "charge" the batteries, don't you?

:D :D
talbot wrote:Question about rinsing a 2hp Honda "after every saltwater use."

My 4x4 manual wants me to repack the differential after any contact with water and to daily change various lubricants if used "off-road". As if that's going to happen.

I rather change .... charge my batteries :)

Re: Outboard Motors

PostPosted: Tue Aug 11, 2015 5:21 am
by GreenLake
talbot wrote:Oh, man. Why do I have to keep learning new stuff? Since getting this last boat, I have had to learn . . .
--structural fiberglass repair
--osmotic blister restoration
--VHF radio protocols
--GPS navigation
--12v electrical wiring
--aluminum refinishing and painting
--steel refinishing and painting
--trailer axle replacement and maintenance
--small dog PFD fitting and behavior

Now small engine maintenance. Will it never end? Will I never get to just be an old man, stuck in a rut, telling the same stories over and over? I didn't even want another boat. My wife made me get it. What was she thinking?


That's not a bug, but a feature -- you never stop learning. You limit the list to maintenance, and using certain equipment, now add all the tricks about sailing the darn thing, and meteorology and what have you. The learning never ends.