more substantial electric drive than outboard trolling?

[rob hodge]

hello, this is my first post, but i've been looking at pocketship for almost two years now.

i live in seattle so i'm looking at building a small boat to handle lake washington, as well as some trips on puget sound. me and my girl have a six year old son and we'd like something we could do an overnight trip in, maybe stretching it out to a weekend, or a day trip when my parents visit.

i got to sit in one and take a look at it when CLC brought out pocketship #1 for the port townsend wooden boat festival last year and really like the boat.

it'll be my first boat owned as well as first boat built.

being in seattle, and having only ever sailed a small sunfish on a lake in northern wisconsin, i'd ideally want to have some auxilary power so i could go upstream thru the ballard locks if i decide to keep it in the water, instead of trailering it, as well as being able to have some power to move around in tight quarters.

however, tacking on a trolling motor or outboard o nthe back seems to ruin a bit of the simplicity and add to the complexity and just overall seems like an awkward way to go.

has anyone else contemplated some sort of electric pod drive kinda setup? permanently mounted to the bottom of the boat, with a 12v or 24v electrical system to power it? possibly a pair of pods, each about the same size as the bottom of a trolling motor, one on each side of the keel? substitute some of the moveable ballast for batteries?

i'm thinking this could give adequite manuvering power, and using a renerative system charge the batteries while under sail. most pod systems i'm seeign are WAY overpowered for a boat this size and silly expensive but ikeep being drawn back to these:
http://www.minnkotamotors.com/products/ ... water.aspx
they state right off the bat that they aren't for use on sailboats... but i've never been afraid of repurpousing things before. maybe coupled with a different motor controller they might do nicely.

anyone else have any thoughts? am i way off base here?

[decurtis]

Rob,
Based on my personal experience with a trolling motor vs a small outboard on my Pocketship I would be wary of using the propulsion system you describe. I had a 55 lb thrust Minn Kota attached to my transom originally and it just wasn't enough power for my Pocketship. My new 2.5 HP Tohatsu outboard has plenty of power and has turned out to much more convenient to use and maintain. Yes, the down side is the small outboard detracts from Pocketship's fine lines but it isn't as bad as I thought it was going to be. The cost is also considerably less than the system you are looking at. My total cost including a outboard bracket was around $850. Your cost I am estimating would be at least $1500-2000 for 2 55 lb trust pods plus batteries etc.
When I was using the trolling motor I always had to worry about whether the battery was fully charged and your cruising distance and time can be quite limited on a single charge. With the outboard and a small container of gas on board I am good for at least 15-20 hours.
I am not positive but I am guessing that maneuvering could also be problematic using the tiller since the pods are fixed. The outboard makes it quite easy to maneuver Pocketship for docking and leaving a crowded harbour.

You can see my setup under this link on the forum
http://www.pocketship.net/phpbb/viewtopic.php?f=3&t=308

[rob hodge]

part of my thinking is that your 55 lb thrust wasn't sufficient, and that the 2.5 hp suzuki you eventually went with was around 80 lbs, wouldn't the 110lbs of two be fine?

as for range, I'm not intending for distance crusing. the most I'd be used in a stretch would be the six miles of the canal we have in seattle between puget sound and lake washington. and if i were to do that i'd probably just trailer between.
Plus, if i do this i'd have a to size a bank of batteries and build a motor controller to control that used regeneration. basically, when under sail, the trolling motors would charge the batteries. even if i left the dock flat-ish, i'd have a charge after a while.

cost might not be as differential as the inital price looks. upkeep on electric is less, gas (and oil on a 2-stroke) add to running costs. might even end up using batteries for ballast and saving some cost there. plus, there's a ton of value in my mind in having it be unobtrusive.

i was thinking that two pods on either side of the keel mounted directly in front of the rudder might give adequate control, especially if controlled independently.

thoughts?

[decurtis]

Just my 2 cents worth, but it just seems to be a lot of extra work for the sake of not having a small low maintenance 4 stroke outboard attached.

But besides that, I would also be concerned about the extra drag caused by the motors when under sail power (especially if you are using them to recharge the batterie). I'm no sailboat engineer but I know John C Harris is proud of the nice clean hull lines of Pocketship and commented in the construction manual that he thought it was important to have the centerboard's pivot bolt embedded in the keel rather than the "lubberly" method of having the bolt head and nut on the outside of the keel.

[JonLee]

I see the allure...a nice clean transom, quiet, "green" propulsion, functional ballast, etc.. You don't have the maintence of the gas motors, the messy fuel, the post-saltwater cleanup. The downside is that dragging those props around would be a pretty definite hit to your sailing performance. And she is a sailboat. On the other hand, I wonder if you could fit it with folding props...

The "range anxiety" would a pretty big factor for me. It's probably managable if you are sailing on the lake. The wind on the lake always seems to die out just a little before sundown. So long as you plan accordingly, you could size the battery pack to get you in. SImilar thing for sailing on around Elliot Bay, where the tidal currents aren't insane.

But, there are so many great cruising ground around here, and you'll probably want to consider the various places you may want to go. I'll usually be sailing out of Everett, so, I've got about a mile of the Snohomish River between me and the open Sound. So, I've got to be able to get up that on an outgoing tide after the wind has died. The San Juans are also on my list of cruising destinations, so dealing with the currents up there is a factor, and being able to make the passage back to Anacortes under power in reasonable tidal conditions is a requirement for me. I might lack imagination, but I can't see doing this with an electric, so unfortunately, there'll be a noisemaker hanging off my transom. Actually, I'm even having trouble figuring out which gas motor best meets these requirements!

So, yeah, I see the allure, but I don't know that I'd do it. i wouldn't want to drag around those props, and for wider adventures on the Salish Sea, I'd worry too much about range.