My fuel effiencient powerboat project , any suggestions?

Hull design

Doppson,

Would your black design be suitable for 8 x 2.5 m as per my earlier designs ? As you know, I am not a naval arcgitect and can only guess to what type of hull design (underwater) is necessary and best, your design seems to suit my needs.. dayboat, electric, max. 12 knots or so, with keel.

I have also sketched a cat build up, based on a combination of party cat's, fojrd boats (look at them they are awesome: www.fjordboats.no), design one on this website in the intro page and of course the Wally power (if only I had the money.... then I would buy the design and make it in holland, not Italy, I have seen enough Italian boats being build in my current job....;-) ). Also based on slender hull box keel.

 

ASM, yes!! im also newbie in boatbuilding. I beleive your spot on!
I actually got to see the fjord Live at Gotheburg boat show in feb this year.. Its big!! and very unpractible but very COOL!

 

Cool

Doppson

Indeed the fjord is very very cool..... i saw it in the Hiswa boatshow this year in Amsterdam, about 1 month ago.... watermouthing good looks, practicality was the least thing I thought when looking at it, though I imagine it depends on the needs and service a boat has the supply. I am not a boater (yet) though sailing along with some friends. Seems like we are on the same idea line here, would you keep me updated to the developments in your design/model making ? I was also looking to make a 1:10 of my designs in plain thin plywood sheet, since the real thing needs to be build out of sheets as well (easiest to my mind), though future interest would possibly mean changing to mould or foam core build up to safe weight. What u think of the cat900 sketch ? Your in Denmark ?

 

yes, we are on the samt track!
YOur sketch resembles the Wally "in fashion designs". I guess you have seen the http://www.ubica-nautic.com/ too. My personal opinion, i like it but i would like to see a some new personal designs from you. Let your own personality reflect on the design with the " todays fashion", if you understand what i mean. I got also carried away in my last design proposal, which i think resembles to much the " the wally design". It's hard not to copy, when the only good looking "new boat desing are wally's" in my opinion.
i will post my progress in here, as usual and im studying i Lund, Sweden.

 

personal design

As i am not a designer at all, to put in my personal features is hard for me, my brain starts rolling when I see something I like, see it as inspiration. I think the personal ideas are in the technics, solar/electric, color scheme and interior set up, not so much the outside... and.. if you wanna sell, you need to be in fashion or have a timeless design, which is hard to find and a once in a lifetime moment to get.

Plus: I see it as a step into electric boating, which will be booming in the near future.. if one has got a good looking, relatively cheap design, well engineered technically (read: monkeyproof) you open a market for a lot of people..... and If I look around in the Dutch waterways, all 7 - 12 m look the same, and all are steel.... so no way they can ever turn to electric drives if they have to budgetwise...

 

Yes, your right. the electric age is comming, and i belive this thread, our discussion will help.

so, what do you think about the box keel configuration for the Catamaran. I don't know what to think, will it be as economical and effecient as we hope?

 

Yes, it is coming... although several electric projects overhere have failed for now, also because of bad batteries and inferior electrics, plus people are unaware of the whole system, while to me it is so much easier.. no fuss with oil/diesel/tanks, ventilation, smell, smoke, noise, etc,etc. and with solar panel keeping up the batteries life, plus additional small gennie, enclosed plug and play type.. no fuss or worries (preparing the vessel for wintertimes, draining lines etc., etc.) and then the costs. As I said, it needs to be monkey proof and able to goo when you want to go, so not a no go under certain circumstances... PLus, one needs to be offered a good design, not a rowboat with an electric drive or 2 to choose from.

I have spoken with a cat designer and on the 9 m he think shoulder height the tunnels will be around 1.2 m typical, making it very narrow for the box keel... simplicity from my side would mean the width of the keel box would max. be the width of the gear to be put in, so batteries or the motor. If you would go slower then your desired speed, I would go for electric pods.. even more space in the vessel, and real plug and ply under the boat, no rudders at all !

I also feel there is much to gain in electricity consumption, like LED lightening.

 

With electric very limited power the cats will never be able to get to very good speeds , as the skin friction is high on cats .

The advantage of the cats is the fine easily driven hulls at HIGH speed, not applicable to a motor that is a couple of hp.

A monohull will probably be faster with those severe power limits.

FF

 

FF:

a 4000+ lbs powercat with -80kw peak engine? do you still think a monohull will perform better?

 

a 4000+ lbs powercat with -80kw peak engine? do you still think a monohull will perform better?

That really depends on what the LOA of the monohull is allowed to be.

In terms of seakindlyness , ability to carry on at speed in rough seas , and ability to carry a heavy load , I would think the monohull (if long , slender and as light) would win hands down.

FF

 

"FF:

a 4000+ lbs powercat with -80kw peak engine? do you still think a monohull will perform better?" Doppson

Depends on which monohull. This one is interesting, shows monohull design is still pretty creative.....and efficient. 26,000 lbs +, 19 mph, 288 kw, superior seakeeping ability, minimal wake. Reduce the hull size and the figures are about 6,000 lbs, 77 kw.

http://www.alsphere.at/dg/index.shtml

 

Powercat vs monohull

FF: I have ssen the DGS site a while ago and it seems it has been quiet since they made it, 2002... I don't know where they stand now ut I also understand is that their hull design is shaped according to following waves, so resizing it may mean rearranging the hull design as well. Yet interesting, it is some sort of keel box hull as well....

I have read a publication from Malcolm Tennant, a cat designer and he recons below 10 m, a monohull could be as efficient since the volume in the cat hulls will be small then compared to the amount of additional weight of the hull sides. By making smart use of the hulls, a cat below 10 m could be superior in volume. Other advantage is the non planning character of a cat so there is a somewhat lineair build up of speed, no need to go over the planning hump.... at least this is what I understand from reading several articles, I am not an expert at all.

 

Doppson.

I think you might be better off looking at a trimaran design like on johnsboatstuff.com and the sketch I made for an 8 m, based upon this hull design.. advantage is the use of a single engine in the front center hull, the aft side hulls could be carying the bateries.

 

35kw-40kw electric motor is all thats needed for 25knots

You can do all the research you want, it will most always be wrong. You can use as many computer assisted programs to try and determine hull speed, it will almost always be wrong.

Trial and error is the only real way to determine hull speeds.

A good example of fast economical hull is the macreggor sailboat hull and other similar hulls. Many think it is unsafe for sailing/motoring etc. Those sceptical are wrong as the hull design works well for both sail/motor. If you use a computer assited program to help determine hull speed, the exact macgreggor sailboat hull design spec wouldnt calculate near the proven speed rating of approx 25mph.

With 50hp/35kw propulsion system the hull will reach approx. 22-25knots. To power a 35kw electric motor for 5+ hours is not too difficult. It would be best to use a combination of battery/small 1-2 cyclinder diesel motor genset. Or all out diesel outboard motor/inboard of approx. 35-50hp. The boat will acheive over 22knots, possibly to 25knots. Range of the vessel could easy reach into the hundred of miles with hybrid diesel.

The hull should be approx. 30ft in length and under 8.5 wide and total weight of approx 4000lbs.

Of course you could double the motor power as you want to use 80kw power electric motor, but this would require more operating fuel and battery capacity and limit range. If you utilized the higher 80kw motor hull speed would probaly reach mid 30knots.

 

Mc gregor

Altura,

You are probably right, though the whole world relies on computer models these days for all kinds of engineering... and not everything is completely wrong. But, the Mc gregor uses the fundamentals we have seen in this forum too, slender almost wavepiercing hull, very smooth surface, and of course light weight (the 25 knots was achieved with emptied balast tank, one person on board and probably mast down, Still a good achievement. It would be interesting to find out what a Mcgregor would do with less weight and no mast at all, would be nice to convert one into a power boatm though the looks to me are not really appealing. I have sen one in the Taiwan Boat show last year, so I know why the price is so low, though the build quality overthere uis excellent unlike people tend to think when they here made in Taiwan.