From: John Paramore <watertoyz@frontier.com>
Subject: Re: [Electric Boats] Electric planing dinghy
To: "rob_linda_2000" <rob_linda_2000@yahoo.com>
Date: Friday, May 6, 2011, 10:12 AM
Here are a few pictures that could be helpful...Hopefully more helpful than tripping over the "send" button as I just managed.
Anyway here are a few shots of some of our toys. I'm really not sure what a planing dinghy is, bour this is the current UIM 48v world record holder. The boat's a copy of a Sorensen A-stock Runabput. In APBA outboard racing it would be powered by a 15 hp OMC. but here We're running Freddies 24v Prestolite outboard. It's a 24v pallet-jack motor mounted on a complex tower Fred made and using a Yamato 302 lower unit.
A look at the outboard...Fred built the leg and mount from aluminum tube and plate. It's suspended from Mercury OPutboard clamps that he's modified to include a jacking screw. The Yamato gearcase is a purpose built racing unit. Yamato makes a variety of racing outboards. This if for the 302 made for stadium racing. In Japan the government operates a network of marine racing stadiums where identical boats/motors are raced in a pari-mutuel format similar to the horse racing we see here. At the end of each season, Yamato makes new boats and motors and refurbished the old motors for sale on the world racing market.
Here's another of Fred's creations. This one's a Craig-Craft runabout he rebuilt. The motor's a Jack & Heintz G-32 turbine starter/generator from a GE J-57 engine. I looks a little down in the water, but that's because Fred was having fun jumping it in a test.
Here's the motor end. The leg and gearcase in this instance is an OMC 18 hp unit. The outsized prop started as a stock 18 hp prop. Fred cut the blades off replacing them with bladed from an OMC 50 hp. The motor was plenty strong...Though rated at 24v they were frequently raced at 96 to 108v without a problem.
Here's my brother Will in a test just prior to setting the 48v Hydro record. The motor's another Prestolite, this time a pallet-jack 12v.
In racing we ran it at 48v, but on several occasions we increased the pack to 72v to race the big spenders successfully. The lower unit here is an OMC 25 hp commercial fishing unit. We picked it because it ran bearings rather than the usual bushings. We also re-shaped the unit with Bondo, measuring amp-draw in tests after each revision to lower draw and increase run-time. We started at about 450 amps and whittled it down to about 200. The tower is a simple assembly of aluminum plate. total motor weight was about 60 pounds. The prop was an OMC power prop reconfigured as a surfacing wheel.
Here's the later similar tower/unit we ran on our 350cc hydros. Again, Mercury clamps and an aluminum tower we built of plate, rough cut with a SkilSaw and finished on a drill-press. The lower unit's a Yamato 302 with a Lee Tietze nose-cone added. The Yamato gearcase begins to turn unstable at about 80 mph. With the nose-cone we ran our 350s 105 to 108 mph in the straightaways without a twitch.
We were pretty brutal with these motors. There weren't any reliable controllers then (early '90s) so everything was strictly on or off using a knife-switch or contactors.
Currently the fastest boat runs about 100 mph on a Lithium pack and a Zilla controller. Where we needed to to to a start point in the past Mike drive4s out from the pits like any other race boat and can make four to six full length passes of the lake before sag begins to show. His pack runs about 80 pounds as opposed to about 500 for lead-acid. The 48v mark is only about 30. Partly that's because we ran as slow as allowed. We had to run 29 or better to match or beat the APBA mark to get submission to UIM but we wanted to avoid denying Emhrys a chance to challenge. We'll be up for the hydro mark soon with luck and I'd like to run Lithium there. I think the lighter weight and better density will fly the hull and allow us to gear up prop-speed. Our goal is to break 50 mph on 48v.
John
On May 5, 2011, at 6:40 AM, rob_linda_2000 wrote:
> Since liveaboards and cruisers anchored here in the lagoon have gotten used to seeing me move around in all weather in my solar powered sailing dinghy "Big Oil", without ever having to buy gas, I do a lot of explaining (preaching),answering questions etc.
> So I got an invitation to assist in the design and electrifying of a planing dinghy. Since I was impressed with the performance/weight of said dinghy, I accepted the invitation and would like ideas/comments/etc from this group.
> Dinghy:
> 16 Feet, made from some high tech foam, so light, that the guy has to BALLAST it. Presently it has a 15 HP in the back and if you open the throttle halfway, it jumps straight on the plane and remains planing throttled back to about half that.
> Range:
> It will only serves as ship to shore tender, 2 15min trips and back at most per day (between charges), so design is for 1 hour usage at minimum planing speed
> Motor;
> DIY outboard conversion using 48V ETEK or simular
> Batteries:
> Lithium 130Ah (for now)
> Charging from solar panels/generator on mother ship
> Question:
> We're trying to establish lowest RPM for planing with the 15HP and needed RPM for planing threshold, but still looking for right handheld tachometer.Any ideas out there, how RPM's of typical 2cyl outboard compares to ETEK/MARS at 48V
> Other question:
> We will be looking for 48V solar controller for lithium. Any suggestions?
> Any feedback is welcome
> Thank you
>
> Rob on Linda
>
>
>
>
>
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