Levi drives

[ted655]

For those who don't have this link
http://www.fastmail.fm/mail/Choongs%20LD170-150.pdf?MLS=MR-**13506*;SMB-MF-SF=Date_1;SMB-MF-DI=25;SAD-MADC-DI=50;SAD-MADC-SF=DN3_0;SMB-MF-TP=0;SMR-Part=;SMR-MsgId=13506;Ust=a859b219!bbb841af;SAD-MADC-TP=0;SMB-CF=148037;SMR-FM=2;UDm=49;SAD-MADC-SpecialSortBy=SNM%3A0;MSignal=MR-GetAtt**2

[Jeff]

Bad link.

[xrudi]

Hi,

I will attach some information to the e-mail. I hope it works.

Best Regards
Rudi

[Frosty]

How far is the prop from the transom? What criteria do you use to achieve this distance? Why is it not as far back as that of an Arneson? Do you use a 'water break' on the trailing edge of the transom? What is your speed prediction on that of an outboard motor of the same HP rating?

[xrudi]

Dear Jack Frost,

The shaft angle of our commercial units are 8 degree. Our racing drives have lower shaft angle. This would natually make the propeller holder longer.
This hull is a normal fishing boat hull. With a 60 hp outboat our fisherman get about 21 - 22 knots.

Best Regards

Rudi

[Frosty]

Thank you Rudy but That was not the question. How far back from the transom is the prop and from what criteria do you use to get this measurement. I ask because your shafts seem much shorter than that of an Arneson. Surely this distance is not guess work and the hull shape will vary this distance?

Im sorry but what do you mean the prop 'holders' longer?

[xrudi]

I think, I did (cosin:). The distance is about 600 -800 mm.

Sonny will have a laugh when he hears your question about the distance criteria. I think his answer would be "30 years of surface drive construction experience".
The "propeller holder" is the piece of metal or plastic which holds the propeller and rudder in place. Our sales people call it "Drive Unit":)

Best Regards

Rudolf Scholz
Naval Architect

[Frosty]

Thank you for yor reply--600 to 800mm So plus or minus 200mm????? Why is it not critical then? Why are the Sony drives so much shorter than Arneson that now make an extended shaft modification?

Surely the criteria would be for maximum utilization of wake fraction? This will vary from boat to boat? Or is it not?

If its not critical then why do you think that your competitors are moving it further from the transom. This will be going on toward twice your distance.

Is Sony right or is Arneson right?

[Frosty]

I have just been to the web site and there are no real measurements available. However it does say that the shafts are standard 800mm. This I take it is shaft length so we still dont know or you dont know ----How far is the prop from the transom?

If this is making Sony Laugh then I am glad he finds it amusing.

[Willallison]

Jack - 1st up - it's Sonny, not Sony, as in Renato "Sonny" Levi. Rather acclaimed in the powerboat world...
2nd - I think what Mr. Scholtz was trying to say is that how they arrive at this would be regarded as proprietry information....

[xrudi]

Thanks!! I'm sometimes not so diplomatic.

The surface propulsion art is in the propeller. We have already too many propeller holders on the market which all do the same thing : " holding the propeller in place". What is needed are improved propeller designs.

We have some development in this direction but it requires a lot of money to produce and test new propellers.

Best Regards

Rudi

[Frosty]

Shall I give up --is this a difficult question, shall I try one more time.

I shall make this reall easy. I want to buy a Sonny drive, I want to fit it to my fishing boat, I have a short parking space, Ok heres the tricky bit, how far does the propeller stick out from the transom?

I really want to know, plus I an trying to give Mr scholtz an opportunity to tell us about his product and talk about it. Discuss the pro's and cons of his drives against others. Can he see this ???? Im sure most of you could. Well almost most of you. Oh well!!! 600 to 800mm shaft length--OK

[xrudi]

Dear Jack Frost,

The propeller is covered by the tunnel rudder to protect the propeller and people from the propeller. You need about 1.2 m aft of the transom for our LD170-150. Other model need more space.

I will send you a quotation direct to your e-mail address. We will have an agent in Thailand soon.

Best Regards

Rudolf Scholz

Naval Architect

[Frosty]

You dont have my e mail address. Can you post the quotation on the forum?

[xrudi]

Thanks, but I think the general forum rules don't allow such direct action. Please contact me by e- mail. We will send you our price list.

Best Regards

Rudolf Scholz
Naval Architect

[Frosty]

There are forum rules about blatent advertising but not about supplying a price that was asked for.

I am sure that other forum members would be interested at knowing how much you sell them for, the price is not on your web site iether.

[xrudi]

Here are the prices Dec 2006 for and LD 170-150. The first number stands for the max propeller diameter. In this case 17 inches.
Thes econd number stand for the shaft diameter. In this case 1.5 inches.
The price for the "Fisherman" unit in galvanized steel without propeller is 2100 $ US ex factory Malaysia.

The price for the "Fisherman" in stainless steel 316L, our normal steel quality, is 3720 $ US.

We also have a version of this fisherman with hyhraulic steering. The hydraulic ram in completly produced in stainless steel 316. The bearings are water lubricated "Vesconite" from South Africa.

We just delivered a Levi Drive 170-150 in stainless steel with hydraulic steering to Ko Pangang (near Ko Samui, Thailand, Paul's Boatyard). They need some good drives for their full moon party:)

Best Regards

Rudolf Scholz
Naval Architect

[Frosty]

Thanks rudi . Thats very interesting.

can I ask you how much you would quote me for a 2 peices 26x26 diamond back with a 2 inch shaft taper and key hub in bronze,-- L&R ? Unfortunately an anode fell off one shaft and it damaged a blade on one prop.

[Guest-3-21-09-10-33]

Dear Jack Frost,

.... We will have an agent in Thailand soon.

Best Regards

Rudolf Scholz

Naval Architect

Rudy, hi, You didn't told me about a new dealer in Thailand. May You send to me his name by email ? By the way I will be in Ko Pangan to try the 170 when Paul will have the boat ready, I told him already.
Luigi

[xrudi]

Dear Jack Frost,

What kind of surface drive do you have? It might be better to buy a replacement from your original supplier.

Less problem with fitting the prop to the shaft. We would require the shafts to be send to us for fitting. The fit should be 60-80 % blue color marked.

Levi Diamond Back propeller are made in NiAL Bronze. They are sized to fit the maximum diameter of each Levi Drive model. To fit the different pitch requirements we have five right hand and five left hand propeller for each model.

These are commercial propellers for commercial drives. Everthing is a bit more solid than on racing drives. We don't like our propeller blades to fly around:)

To give you an example. A "Diamond Back Propeller" for a LD 240-250 (up to about 300 hp) would have a diameter of 24 inches and the hub would be for a 2.5 inch shaft.

Price 2624 $ US Dec.2006.


A "Diamond Back Propeller" for a LD 280-300 (up to about 500 hp) would have a diameter of 28 inches and the hub would be for a 3 inch shaft.

Price 3974 $ US Dec. 2006.

Your requested propeller 4 bladed 26/26 for a 2 inch shaft is not our standard size, but we can do a special propeller for you.
Please request a special quotation from our sales department when ready to order since the prices for propeller are following the world copper prices and going up constantly.

GL certification is possible at extra costs.

Best Regards


Rudolf Scholz

Naval Architect




You can have GL certification at extra costs.

[Frosty]

Aha I have found a drive manufacturer that freely talks about propeller positioning behind the transom. A point that some think is a trade secret amongst drive manufacturers.

Sea rider surface drives web site is very interesting and positions its propeller one half of the diam of the propeller away from the transom, making this a very compact unit.

So for all the mathamaticians interested it would appear that a 26 inch prop would be 13 inches from the transom.

As I have tried in the past to find the criteria of this measurement, I am still not sure of it. Drive manufactures state that the cleaner the water the better the performance of the propeller, yet keep moving it further away.

[Frosty]

[QUOTE=xrudi;118249] We would require the shafts to be send to us for fitting.



The props were ordered and made in NZ and the shafts were made near the boat in Sydney. A standard taper is a standard taper.

I can remove my props with out getting my hair wet. Hauling the boat and removing shafts???? then posting a 2x 30 kilo shafts to you and back???

Rudi thats more than the props cost.

[xrudi]

Dear Jack Frost,

To my knowledge there is no standard popeller cone. The American's use one inch to a foot (1:12). The European use (1:10). We have had also a lot of other tapers in between. The key is an other problem. Eveybody seem to make a different key grove. The key grove should be formed like a spoon at the end.

If you provide us with a shaft, you get a perfect fit. (60-80 % blued). In this process the shaft is coulered and than fit together with the propeller. The marking inside the prop hub should be 60-80%. This can be certified by a classification society at extra cost. We prefer Germanischer LLoyd.

If you don't need such precision, measure your shaft taper carefully and make us a drawing. We produce according to your drawing. You might also employ a local workshop to do the final fit. The "risk of the fit" is in this case yours. But remember, on a a 1:10 taper one 1mm error moves in the propeller 10 mm. :)

A few e- mails ago you wanted to pick up an LD 170-150 with your truck from Penang and bring the unit to Thailand. Use the same truck to bring us the shafts:)


Cheers Rudi

[xrudi]

Dear Jack Frost,

I think there is no problem to remove the shaft when the boat is floating. I have done this several times for my own catamaran and also on bigger ships. All you need are two good plucks (inside and outside) and a good bilge pump:)

Cheers Rudi

Naval Architect

[Frosty]

Dear Jack Fro
A few e- mails ago you wanted to pick up an LD 170-150 with your truck from Penang and bring the unit to Thailand. Use the same truck to bring us the shafts:)Cheers Rudi

You mean drive to Pinang from Thailand and back twice? Or will you make the two props while I wait?------ It doesnt matter.

Your props are nearly as much as seafury's, and they made the taper perfectly once.

As far as buying a drive unit, youve convinced me to make one myself as the shaft length is not critical 600-800mm. wont be too difficult then.

I also do not like the exhaust grills in your drives. How can you antifoul inside the drive to keep the grill clear of barnacles

On a shallow draft vessel as your fishing boat as an example directing the exhaust to the prop would not be necessary any way.

[xrudi]

Sonny Levi inspired propeller holder (Drive Unit)

Dear Jack Frost,

You should have told me that you want produce a Sonny Renato Levi inspired propeller holder (Levi Drive). You are not the only one! We come across quite a lot of copies world wide. Some even use Sonny's record breaking boat name in their company logo.

If you need some drawings of the drive unit, please go to Sonny’s second book “Milestones in my Designs”. You will find a complete set of drawings there. This properly the cheapest way to get some inside knowledge about “surface propulsion”.

The LD 170-150 does not have an exhaust diffuser (grill on the back). Too expensive to produce.

Your mentioned shell problem does not exist.
Shells don’t like to grow in the dark, Our customer don’t find it difficult to clean the diffuser with a pressure cleaner and apply antifouling with a spry gun. It is much more complicated to weld this structure together.


Merry Christmas

Rudolf Scholz

Naval Architect

[Frosty]

Rudi,

A merry Christmas to you too.

I have read the book, Sonny very kindly lent me his own personal copy some years ago.

I thought you had exhaust vents? Sorry -- difficult to see.

[jmac]

Jack Frost
I am using this drive on my boat. Of the manufacturer's that I have seen this one seems to stick out less than the others. My use is for speeds up to 28knots. I tend to agree with the earlier statement about propeller design being what it is all about. They give all there dimensions on the web site. (The links works in explorer only)

http://www.q-spd.com/SD%20Series.htm