Do you have something to say about "Jinx" ?

I agree with apex ! Torqeedo in Turkey is also too much money ...

It is the one way of Composites manufacturing,

result of vacuum infusion process is better than hand lay-up process.

My english is not good enough,sorry.I didn't understand what you mean ?
"What do you think is vacuum infusion Cenk? Does it infuse strength into a weak material? Or maybe just resin?"

 

Genc

I know what vac. infusion is, I build yachts. But you can NOT use a foam core panel as a frame! No matter how you put the glassfiber on it!

Richard

 

Nostalgia !

The subject boat is a very dated design. It was a good one in its' day but it is heavy by modern standards. The design is as good as you need but the construction details are a bit much. Keep in mind that there was no epoxy in those days. I would urge you to adapt modern techniques to this design if you build it. Use thicker skin and fewer longitudinal members. Get the Glen-L book about ply construction, stitch and glue methods, etc. Save a lot of time and build a lighter, cleaner, boat. Any modern outboard of 300ccs or so will make it a real fun toy.

The 20 cubic inch engine on the plans was a fore runner of modern engine design. The text shows the engine with a Quicksilver lower unit which was a race engine optional (extra cost) item. The performance claims in the text of the article are a little optimistic. Boats and motors of that vintage were hard pressed to ever see 40MPH except in the hydro classes. Nonetheless the boat will go plenty fast and may exceed 40 with a modern engine and appropriate prop. At speed this boat will beat you up pretty badly, even in a very small chop of water. Don't let that stop you from all the fun. Your bruises will heal in a few days.

 

Beware the ad hype.

Someone please explain how the Torqueedo can defy the laws of physics. How can 1Kw exceed 2900 watts? I reckon that is some kind of hogwash that was dreamed up by a sneaky marketing department that had no interest in truth or reality. A single kilowatt is a single kilowatt and it can not be 2.9 Kw.

FWIW, I like the delightfully quiet and smooth electric propulsion on my little dinghy. I do not expect high performance from it. It is capable of about four tenths of one HP. My voltmeter and ampmeter does not lie. Not a Torqueedo, it is only a modest Minkota.

 

If you build it with the old style frames, you will have good, solid cross grain wood to screw the stringers and battens to. If you use plywood you will have plywood edges to screw into, which are weak. If you use fiberglass of some kind, you will have to figure out how to attach the stringers to the frames.

 

Messy,
Bertku has his own physics, do´nt bother. And the advice for El. power for such boat shows real professionalism, does´nt it?

 

He's trying to tell you that vacuum infusion doesn't make things stronger, it is just a different way of getting resin into a laminate.

 

Certainly not true! The propeller doesn't care how the power to rotate it is made. 1 kW = 1.4 HP, that is about 1/3 of 4 HP and a typical new 4 HP outboard will produce close to 5 HP in reality (measured from propeller shaft).

There are also some test results, that show a 2.5 HP Mercury is slightly faster (5.5 kn vs. 5.3 kn) than a 2 kW Torqeedo although they have about the same power. Unfortunately this is in swedish, but you can read the numbers: http://www.torqeedo.fi/testit/to_vi_bataegare_1208_svenska_se_.pdf


I have owned a Jinx and it reached 15 kn with 4.5 hp Mercury (from 70's, actually only 3,5 HP) with the standard propeller. Certainly you can not do that with 1 kW electric motor.

 

check this site out , it might be of some help.
http://www.boatracingr11.com/Sorensen_boats/sorensen_Restorations.htm

The Desivla hull was state of the art at one time .
I have seen on at close to 90 HPH . 50 is no problem , please to have flat water .

 

A typical build

 

What about weight decrease!
Vacuum infusion makes more lighter than hand lay up. Also more powerful than hand lay-up.

Mechanical properties depends on Manufacturing method I think,
for example,
prepreg composite manufacturing is the one way of composite manufacturing but aero-factorys make incredible tough materials.

 

I see what you mean.You are more experienced than me I think.Which method do you suggest me to manufacture frames ?.I want to light,strong frames also i don't want to use old methods frame manufacturing.

 

Hp vs Torque

Hp and torque are measured independant of one another. Electric motors

have a great deal of torque compared to gas outboards. So, although the

numbers don't add up, a little electric motor really can deliver much more

power than it's kw rating lets on.

Tom

 

Most of these older runabouts are actually pretty efficient hulls, although rough riding, they milk a lot of speed out of a small outboard. For running around on an inland lake that isn't very rough, they are a lot of fun for the buck. If you want a classic kind of boat the Jinx isn't bad at all.

The old methods of making the frames and building the boat are probably a bit of overkill if you use epoxy too, but since these are pretty rough riding boats they tend to take a bit of a beating. In time, if they aren't built pretty stout, they get flexible and after a while start to come apart. Build it by the plans and you will be fine for a long time. I'd add a layer of 4 oz fiberglass to the outside to seal it better and enjoy.

Properly built, these kind of boats don't weigh much more than 120 to 130 pounds, the bottoms are 1/4 inch plywood and therefore pretty light. Thickening the bottom will allow less framing, but the plywood will be harder to bend and a lot of folks think that they'd rather do more framing and have the skin thinner and easier to bend.

If you look at the Glenn-L site they have a lot of customer photos showing boats in progress. Between the photos and the plans I'm sure you can do figure out how to put it together. Also look on Stevenson's site and download a couple of other plans and you will get the general idea as to what to do when.

 

No it can't, unless you are overloading it. Power is power and it is measured in kW or HP for both. At lower rpm an electric motor may output much more power than a gas one, but that is pretty much useless for a propeller driven vessel, especially this light and fast, since at low rpm the power needed at propeller shaft is not much.