yup.. didnt reply earlier to this, didnt look at what type of hull it is but twin 302's is a pretty safe guess its a big power planing hull..
the length is nice, basic formula being waterline length sqaure root x 1.56 for mph displacement speed (6.85mph) and x 0.8 to be within efficiency (5.48mph)..
but (and its a big one) at displacement speeds that type of hull is going to create tons of turbulent drag for its transom shape and displacement running depth, which about rules it out as an efficiency minded electric conversion now (darnit!). 170x2 hp is really big for something electric to try to replace, performance and range? oh heck no!
it is what it is pretty much.
if you see a 30+ft light-sleek fiberglass sailboat hull to play with and work up, you're more likely to come up with something neat-efficient-nice, but it isnt likely to be anything "fast".
I've seen a couple commercially built electric speedboats advertized, pretty amazing but really-REALLY expensive too!
I like this one as a concept no doubt: www.metacafe.com/watch/1608040/solar_electric_speedboat/ the Czeers MK1.
80kw (106hp) motor, tons of solar cells (14 sq meters), battery charge time and range "mysterious"! -and so is the price, but it claims to have run at 30 nauts.
also like: http://www.storerboatplans.com/Solarboat/solarboat.html the mundoo 3,
claiming 4.5 nauts (5.17mph) on just its solar panels alone, with a top speed of 8-9 nauts. they might do better with different solar panels too.
of course, the mundoo's are slower solar-electric cruisers for calmer waters, and theyre scratch building projects. something like that will run about forever and about for free once built, is pretty cool. as a design it also has me wondering, would its performance be better as a sternwheeler where prop-slip is so much less a factor?
(might be silly and maybe not, idk, I'm a rookie!)
I'm sure not saying "hey you cant do that!", just trying to point to things within reason-realities of electric powering boats, its my understanding of the real limitations about em.
--- On Thu, 4/19/12, Eric <ewdysar@yahoo.com> wrote:
From: Eric <ewdysar@yahoo.com>
Subject: [Electric Boats] Re: 28 foot fiberform conversion
To: electricboats@yahoogroups.com
Date: Thursday, April 19, 2012, 1:48 PM
Hi Larry,
It looks like the Fiberform 28 is a samll cabin cruiser.
The short answer is that plug-in electric that costs the same as your repower will deliver greatly reduced performance and severely reduced range. You could consider a hybrid, but it will drive the cost higher. For a power boat, the math just doesn't work out yet. Check back in a decade and maybe the echnology will have advanced enough to consider it, but it will probably still be much more expensive than ICE for similar performance.
Fair winds,
Eric
Marina del Rey, CA
--- In electricboats@yahoogroups.com, "Larry" <lpedgin2@...> wrote:
>
> Hello, I have a 28 foot Fiberform that is currently powered by a pair of Ford 302's (170hp OMCs). She has been out of the water
for 15 years (previous owner managed to sink her while removing the port fuel tank). I was considering doing a repower with upgraded components, but since I need to totally refit her anyway, I am thinking electric. First question: where to start? Second question: is it worth doing it? thanks!! Larry Edgin, Tacoma, Wa.
>
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