electric Outboard Mod

[GreenLake]

Good explanation. The DSII and DS1 really are different beasts.

[K.C. Walker]

Talbot,

Have you considered reinforcing the cuddy floor from the top side instead of underneath? It seems like you could add 3/8 plywood in the area just inside the cuddy door and far enough forward to include battery box opening. Maybe add a compression post between your box opening and the mast step compression post?

Maybe you could even go to 1/2 plywood. It seems like you might be able to fabricate a battery box out of plywood, epoxy, and fiberglass reinforcement that you could use as the compression post attached to the reinforced floor and the hull. This way the floor would be bearing a lot of the weight of your batteries. It seems like this should stiffen up and strengthen that whole area of the boat.

Just some rambling thoughts from a DS1 sailor that uses a gas motor.

[talbot]

I like KC Walker's thinking on this. I guess the point is, the geometry of a double-battery installation is very different from a single-battery installation, and the solution may be very different from what I came up with.

I have a general question about the whole issue: Why invest in such a heavy electrical system on a dinghy? The weight of each battery exceeds the weight of a gas motor, before you even add in the weight of the motor itself. Almost half the carrying capacity of the DS (600#) is committed to the electricals, which limits the ability to carry additional crew, coolers, camping gear, etc. I understand that if you have a 24-volt Torqeedo Cruise, you can't take advantage of the engine without the 24-volt system. But I thought this started with the concern about extending the range of a 12-volt battery. (That is, it sounded like the batteries will be wired in parallel, not in series.)

I see it as a diminishing-returns function: A small electric motor and single battery weigh about the same as a gas motor and have the efficiencies of free (solar) fuel, fumeless operation, and double-duty power for lights. The second battery seems like too much of a good thing when you consider the weight, long recharge times, relatively lower thrust compared to gas engines, and the extensive modification required to install the batteries. If the motor needs to be powerful enough to get you in from the ocean against an ebb tide, 24 volts or a gas engine are probably necessary. But if the motor is for occasional use on a becalmed lake, a single-battery electric should be sufficient. If you go on a long trip where one battery might not be enough, you could always bring aboard a second temporary battery as a backup. It could be stored anywhere and hooked directly to the motor. (That is, you wouldn't need to open the well to remove the dead battery. Just disconnect the motor from the built-in wiring and attach it to the temporary battery.)

[GreenLake]

A number of things. Where does the 600lbs load limit figure come from for the DS? Is that what's on the mandated sticker for newer boats? Because it seems low. I've sailed both DS1 and DSII with substantially higher loads and can't say that the weight was an issue - although with six adults on board eventually you'll run out of room

Weight is not equal weight. If all the weight you are adding is at the transom, you will impact the sailing characteristics of a DS much more negatively than if most or all of that weight is in or near the cuddy. Having a gas outboard permanently mounted in the rear will push down the boat and create drag from a submerged transom. Worse if the outboard is oversized.

When I bring a trolling motor, most of the time I keep it in the cuddy the whole trip, unless I need it to leave the dock or have a bridge passage planned where I know I'll need it. As the motor is light enough, I can mount it while underway. That further reduces the issue from weight at the stern.

Ideally, I would use a 12V NiMH battery, or even a LiIon one. That would save weight - a lot of it: the batteries for a Torqeedo, for example, are light enough to clip onto the motor itself. I'm too cheap for that.

The need for two batteries instead of one is largely reliability for me. I rarely anticipate running down even one; but I have had batteries die without warning. Needing to switch batteries under way is rare enough that I would never dream of installing a switch. I have obtained cables so I can run the motor with the batteries up front. In the past, I would move the active one to just aft of the CB trunk while motoring.

The rest is preference: I put a premium on silent operation, on not having fuel or exhaust fumes, not being able to contaminate the water, an not having to store gas around the house - with the attendant issue of it going bad. And, I admit, I seem to have two left thumbs when it comes to small gas engines: I find that they quickly become unreliable...

I curious about the stress cracking. My understanding is that in the DSII the CB trunk is tied into the lower end of the bulkhead that forms the cuddy opening. That should really stiffen the whole thing, just like the thwarts do in the DS1.

[talbot]

I totally agree with the "light-electric" approach, exemplified by a 12-volt Minn Kota or self-containted Torqeedo Travel. A second battery that doesn't require permanent installation seems like a reasonable backup. What I've managed to do (after rambling for two days) was talk myself into opposing two-battery fixed installations for the DS II. It would involve considerable violence to the boat, a great deal of work, and a lot of weight that you can't easily remove when you don't need it. There are times when you want a powerful auxiliary--either a gas motor or a 24-volt Torqeedo Cruise. We sail in one estuary where we can see and hear the Pacific breakers hitting the bar. We pretty much only go out on a flood tide or a strong onshore wind, because our little Minn Kota won't push us against the current. However, a 2.5 or 3hp gas motor would be cheaper, lighter, and more removable than a two-battery electrical system.

Oh, yeah. The 600 lb load limit came from a 1979 brochure from O'Day. I think we've all loaded our boats way over the limit. That doesn't mean it's a good thing. For instance, jeadstx told me that on the last Texas 200, his DS II, with two people and week's worth of supplies, rode so low that they were taking water continuously through the CB uphaul in the cuddy.

[Alan]

Alrighty, then. My long response to previous posts went poof.

Tomorrow's our big-deal holiday bash. A horde is arriving, and my crew would like me to continue as her crew in aid of the cause.

Lots to say on this, some of it bound to be helpful. Later...

[TIM WEBB]

I ran trollers for many years, first a 36# then a 45#. They were great for inland lake daysailing. Didn't do a whole lot of boat modification to accommodate them, just a battery box mounted in front of the mast stub in the cuddy and some fat wires back to the stern.

When I started to do some extended multi-day trips, mostly in the saltwater of the ICW, it quickly became apparent that the troller was not adequate. Not to mention that it was not a saltwater motor, and it's life expectancy was not long in those conditions. All I had to do was look around at the other boats, and nobody else had one. When I had to ask ChrisB to take me in his boat to pick up/drop off my wife and daughter at the IRLC in June because I was afraid my boat might not make the trip, I decided then and there that I was going to get a gas outboard.

Did a lot of research and searching, and settled on a 2 hp Honda 4-stroke. It's already proven it's worth, once last month getting me out onto Lake Monroe against a north wind that in the past the troller has failed to do, and again this week on a 3-day cruise up in and around Lake George and the St. Johns river, where we covered 40 nm in 3 days, but we motor/sailed about 10 nm of that through narrow, shallow, twisty channels.

No, I don't like all the negative aspects either of the gas vs. electric, but for the kind of sailing/cruising I want to do more of, it's the lesser of two evils. I will keep the 12V system in place, as I also use it to power the stereo, as well as several cigarette lighter outlets I use for charging the GPS and VHF, as well as an electric stove and kettle. Ain't no propane on The Red Witch! ;-P

[talbot]

Thanks. What's the shaft length on your Honda 2hp?

[TIM WEBB]

It's a standard length shaft Talbot, and plenty long enough. I made a bracket to fit to the existing motor mount base on the transom:



With the motor clamped to that, the cav plate is about 3" - 4" below the water surface at rest. The motor tilts up and locks in place far enough to keep the prop out of the water while sailing, too.

[Alan]

I think I was a little fuzzy in my first post on a two-battery installation. The main reason I want to install 12-volt batteries is to connect them to the Torqeedo through an inverter and the Torqeedo AC charger. The manufacturer claims you can do this while the motor is in use, and thus extend the range. I don't want to create handling or stability problems with the added weight, so I was looking for the benefit of other people's experience.

I'm with GreenLake on two batteries vs one, having had a nearly-new battery fail on the water a couple of years ago.

However, it suddenly dawned on me that I'm getting ahead of myself. I should run the Torqeedo in a marine engine test tank (that's a fancy name for a plastic garbage can full of water set below the transom) and see if hooking up a 12-volt battery will actually do much in the way of extending the range. If it doesn't do much, time for Plan B.

I think I can install two batteries in such a way that they and their boxes are easily removed, and also so the centerboard lines on the cuddy floor aren't disturbed.

And, if I save the cutout pieces of cuddy floor and put edges on them to turn them into hatches, I'll be able to put them over the battery holes and say "what batteries?" if the whole battery-plus-Torqeedo thing turns out to be a bad idea.

[talbot]

Hatches sound like a good idea. Another good reason to not cut through the support.
BTW, I stressed a lot about the CB uphaul line getting hung up in the box or wiring, but it has never been a problem. I made my own hardwood track slug with eyestrap that slides up and down in the mast section in the cuddy. The uphaul block is fastened to the eyestrap, and I moved it up to just clear the battery box. The uphaul tensioning bungee goes to the same point. The wiring in its split-comb conduit curves outboard of the eyestrap to the breaker and charge controller (also mounted on track slugs). So far, I've never had any fouling or shorts.

Reading over this post, I think I've never used so much jargon in a single paragraph. We should start a new jargon thread. My goal: all nouns and verbs to be jargon. Only other terms allowed will be prepositions, articles, adverbs, and adjectives. Extra points for jargonizing any of these parts of speech (e.g., abaft, slab-reefed).

[Alan]

Splice the mainbrace!

[talbot]

That's OK, but you have a non-jargon article in there. What we're striving for is all jargon, all the time. Like the advice:
"Snapshackle springlines athwartside chainplates."

You can tell it's high quality jargon, because the spell checker flags every word as incomprehensible.