 |
 |
|
|
 |
 |
|
|
|
|
|
|
|
|
 |
|
|
|
|
|
|
Forums IJCA Forums
|
|
|
|
|
|
|
|
|
|
IJCA Forums
|
|
|
| Author |
Messages |
|
Hans Spiller
Posts:8
 |
| 04/23/2007 8:34 PM |
|
The present class rule on the subject of outboard motors reads:
3.8.8 One outboard engine with a minimum weight of 14kg, which when not in use shall be securely
stowed under one of the main berths or aft of the sill of the companionway.
3.8.9 There shall be a minimum of 2 liters of motor fuel carried in reserve when the boat crosses the
finish line for the last race of the day.
Until recently, the rule required that in addition to weighing 14kg, the motor be rated at least 3.5 Horsepower. The change was made because many national authorities are banning 2 stroke motors for environmental reasons, and a 3.5hp 4 stroke motor weighs 20kg or more.
In the last few years, major advances in electric motors and their control systems, and batteries have revolutionized electric motor use. In particular, AC modulated control systems and brushless motors have raised efficiencies to 85% or more (compared to a gasoline motor which struggles to reach 30% efficiency), and Lithium technology batteries have been achieving remarkable power to weigh ratios—driven largely by the portable computer and cellular phone business. Electric outboards no longer are just “trolling motors.” Now they can be real motors, with real range and power.
An example of such a device is can be found: http://www.torqeedo.com/en/hn/home.html. This German firm makes 3 motors, with input power ratings of 400, 800 and 2000 watts. A horsepower is 746 Watts, so these compare to a little more than ½, 1, and 2.75 hp; however, the drive train appears to be more than twice as efficient as conventional outboards, so 1, 2 and 5.5 hp is probably closer. They claim the big one is equivalent to a 6hp motor. The little two weigh 12kg including the battery, which appears to have a range of 3-11km (depending upon speed) for a boat like a J24 (their nearest example is a Dragon, which is a little heavier but shorter). The rechargeable Lithium Manganese batteries weigh 3.5kg and you can swap them for more range.
The point is that this is just the start of an inevitable trend, which I think we, as a class, should embrace. I propose that we adjust the rule to read something like:
“3.8.8 One outboard motor and power source which together weigh at least 16kg, which can drive the boat at least 3 knots in calm conditions, with a range of 8 nautical miles. Range is to be measured from when the boat crosses the finish line for the last race of the day.
“3.8.9 The motor and fuel, when not in use, shall be securely stowed under one of the main berths or aft of the sill of the companionway.”
(my 14kg 3.5hp 2 stroke can push the boat a little faster than 4 knots at a fuel consumption of about 4.5nm/liter.)
I think electric motors are the way of the future, but I don’t think we should care if you get the power from Gasoline, Electricity, Jet thrust, Solar Power, Hydrogen, Coal, compressed air, or space aliens, just as long as the racing weight is similar for everybody and it’s safe to operate, meets local regulations, and has enough power and range.
-Hans Spiller
|
|
|
|
|
Lorne Chapman
Posts:149
|
| 04/27/2007 3:32 PM |
|
This is an interesting idea and in the age of the race to go green we should give it some serious thought.
Before we can start to consider the rules aspect, some practical, "proof of concept" trials need to be done. If anyone who reads this has access to a distributor of any of the motors Hans mentions, it would be good to arrange to borrow one to try on a J/24. If you can, do some tests and check the attainable speeds, both in a significant chop and flat water. Take pictures and share the results.
There also needs to be some work done on an acceptable performance specification for any alternative power sources and tests done that show what each of the options to be considered can deliver.
This also raises another question about whether an electric motor would cause us to rethink the battery issue - right now we can carry 25 kg batteries - that in most cases just power a few cabin lights. Does the battery for the electric motor come under the battery in the boat rule - or is it separate. Issues to think about and do some investigation of options. |
|
|
|
|
|
| You are not authorized to post a reply. |
|
|
|
ActiveForums 3.7
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Home | News | Events | Organisation | J24 History | Forums | Classifieds | Tips & Tricks | Links
|
|
|
Copyright 2008 by IJCA
 Terms Of UsePrivacy Statement |
|