T-Pain Is On A Boat: RE: [Electric Boats] AC vs DC motors [1 Attachment]

Friday, July 29, 2016

RE: [Electric Boats] AC vs DC motors [1 Attachment]

[Attachment(s) from Jerry Barth included below]

David,

You should check out John Shuttleworth. He just did a 140 ft trimaran that is currently going around the world. I've been following him for about 30 years now and his boats are always good. Adastra also has amazing fuel economy for how big it is, something like 3 times better than other similar sized boats.

Jerry Barth

http://www.shuttleworthdesign.com/adastra.php

Sent from Mail for Windows 10

From: David Adams lonzim.adams@gmail.com [electricboats]
Sent: Friday, July 29, 2016 3:27 PM
To: electricboats@yahoogroups.com
Subject: Re: [Electric Boats] AC vs DC motors

Hi Kevin,

Yes, I have already contacted a Naval engineer and gone through the preliminaries.

However, I felt he wanted to press straight in to designing the vessel before seeing if it would work.

In other words, my initial criteria are.

Multihull in about LWL 80 - 100' (The closer to 80 the better, 100' is just getting crazy)

Total beam of about 35 - 40'

Hull beam to length ratio of about 10:1 preferably 12:1

8-10kt cruise with 15kt max

2 x 100kW (134hp) electric motors (continuous rated)

2 x 120kW backup generators

Hull material aluminium

Displacement of about 60 tons (metric) Might end up closer to 70tons

Approximately 70kW of solar PV on roof.

NA's answer was, well, we have to design it first to see how much power we need to drive it through the water.

(Time to find another NA)

I'm not going to spend 40k designing a boat that doesn't work. So...

I'm out here asking for some advice and ideas.

I realise it's not an easy thing to answer but does anyone have any idea if the above is doable?

Or am I just way out of the ball park?

The kind of questions I'm asking myself are, how fast will I be able to propel the boat if I'm running on PV alone and feeding the two motors 30kW each? Is it even plausible?

Will 200kW total push the boat at an 8-10kt cruise and 15kt max if I've got both generators fired up?

Will it even get close?

Before I have some idea of these things, I'm not prepared to leap in. It's not play money.

Even the 40k to design it and produce the cad cutting files isn't play money.

So can anyone please offer some pointers / opinions?

Thanks for all the input so far folks, it's really appreciated.

Best regards

Dave