Re: [electricboats] What if...? Hybrid conversion for Trawler???

4-5 MPH is more realistic from a 7.6kW generator. Most motor and controller setups will require DC power input. A simple bridge rectifier may make that possible. For that large prop, you will need a large reduction, most likely near 4:1.

Scott Masterson

On Fri, Feb 7, 2020 at 7:07 PM john via Groups.Io <oak_box=yahoo.com@groups.io> wrote:

The following scenario is a "what ifffff" for a "trawler" class cruising boat.

These boats are generally powered by old diesel engines - typically 120-275HP each (twin engines).

If the diesel engines died for whatever reason, could I replace them with some kind of electric motors, and run the electric motors from the still working generator?   I'd still be burning some kind of fuel, but I'd be rid of two large diesel engines (that I might not be able to get repaired).

Here are the specs for the boat:

Length:  38'

Beam:  13.6'

Draft:  3.6'

Weight:  21,000 pounds

Semi-displacement hull.

Props:  2, bronze, 24"x26"

Gear ratio (if the transmission was kept) - 2.5

Hull speed for the boat should be about 9.5mph

Here are the readings that were taken during a survey of the boat (RPM's for both motors):

700 RPM              3.3MPH

1000 RPM            5.6MPH

1500 RPM            7.5MPH

2000 RPM            8.8MPH

2500 RPM            9.25MPH

The current generator on the boat was a 7.6KW.

If I wanted to be able to attain a max speed of 7.5MPH, at about 1500RPM for each motor, with 24"x26" props, how big would the electric motors need to be?

Can I drive each motor on 3KW or less?

Can this be done practically??

Thanks,

John

_._,_._,_

---

Groups.io Links:

You receive all messages sent to this group.

View/Reply Online (#30241) | Reply To Group | Reply To Sender | Mute This Topic | New Topic

Your Subscription | Contact Group Owner | Unsubscribe [newarmyguitar24@gmail.com]

_._,_._,_