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Conference unifix::sailing

Title:SAILING
Notice:Please read Note 2.* before participating in this conference
Moderator:UNIFIX::BERENS
Created:Wed Jul 01 1992
Last Modified:Mon Jun 02 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:2299
Total number of notes:20724

1088.0. "Self-pitching propeller" by CDR::SPENCER (John Spencer) Wed Jan 04 1989 09:23

[The following is transcribed in its entirety (w/o permission) from the
Oct/Nov '88 issue of Multihulls Magazine.] 

            SELF-PITCHING PROPELLER IMPROVES PERFORMANCE

A self-pitching marine propeller from Britain has independent, freely 
pivoting blades which, automatically, adopt the most efficient pitch -- 
ahead, feathered, or astern.  This compares with fixed-pitch propellers 
which only attain their maximum efficiency at one speed or power setting.  
It costs less than comparable equipment.

The Brunton-Weil Autoprop is available in two- and three-blade versions.  
All blades are independently free to pivot through 360 degrees on 
grease-free self-rinsing bearings and are offset to the pivot axis.  The 
pitch setting taken up by each blade is determined by a combination of 
centrifugal forces and the hydrodynamic forces, which act on the 
specially-shaped blade face, and vary in relation to the vessel's movement 
through the water.  Wind assistance has the effect of coarsening the pitch 
to the optimum, to allow the most efficient use of the engine.

The Autoprop covers numerous requirements which ranges from maximum speed 
using only the engine, or sailing with minimum engine assistance.  All 
conditions are automatic, and the blades feather immediately when the 
engine is switched off.

On yachts with steeply angled shafts, the feathering is particularly 
effective when compared to a geared propeller.  Each blade takes up a 
natural line of least resistance; whereas, with all blades of a 
conventional propeller turned to the same angle, there is still a 
significant amount of drag.  It gives enhanced performance both ahead and, 
particularly, astern.  In reverse gear, the blades turn themselves through 
180 degrees to assume the same angle of attack as ahead, and with the 
leading edge still leading.

Simple to install, the unit fits most existing tailshafts.  It is 
available in 10" to 20" sizes, right-handed or left-handed, suitable for 
auxiliary-engined yachts with inboard engines up to 59.7 kw.  All 
components are made of nickel-aluminum bronze or grade 316 stainless 
steel.  

Inquiries from prospective U.S. agents are welcomed by the company and may 
be sent to:  Brunton's Propellers Ltd., Mr. P. Goodchild, Sudbury, 
Suffolk CO10 6ST, England.  Tel: (44) 787 73611.  Telex 98400.


T.RTitleUserPersonal
Name
DateLines
1088.1Going well in UKCHEFS::GOUGHPPete Gough @REO 830-6603Wed Jan 04 1989 10:016
    A good write up in UK Magazine Practical Boat Owner . The prop is
    now fitted as an option on the MOODY 346. The article is long but
    I would be happy to put the conclusions etc here if there is interest.
    It is a very expensive piece of hardware....
    Pete

1088.2When they come to...CDR::SPENCERJohn SpencerWed Jan 04 1989 11:549
>>>    It is a very expensive piece of hardware....

How much?  Given that it apparently dispenses with any sophisticated 
internal gearing, perhaps it's not too outrageous.  Besides, by keeping it 
within some reason they can have the perfect market niche:  All those 
sailors just waking up after fainting over the asking price for a Maxprop!

J.

1088.3Same price as a DECCA....CHEFS::GOUGHPPete Gough @REO 830-6603Thu Jan 05 1989 05:237
    I was quoted 300 Pounds Stirling plus Value Added Tax last year for a
    prop suitable for a MOODY 28. I intend going to the London Boat Show 
    next weekend and will try and find out the current price range. 
                             
    Pete      
              

1088.4MORE INFO??POLAR::HEWITTFri Jan 06 1989 09:2516
    Pete
    
    I am very interested in more information about this prop such as
    price, reliability, user comments etc.  Would it be possible to
    get a hard copy of the article out of the magazine?
    
    Also How about more information about the magazine itself. I am
    in the process of building a 38 foot cruiser and appreciate the
    type of information one can get from  *.PRACTICAL.* type magazines.
    
    Thanks  in advance for your help
    
    Rick 
    M/S KAO4-1/6C
    

1088.5CHEFS::GOUGHPPete Gough @REO 830-6603Fri Jan 06 1989 09:359
    I am off to the London Boat Show either this weekend or next,depending
    on how the better half feels. If they are exhibiting I will pick
    up what I can, if not I will copy the article and send to you. I
    was wrong it was in a magazine called Yachting Monthly, the other
    popular magazine is Practica Boat Owner. They do overseas subscriptions
    so I will post the addresses here next week.
    
    Pete 

1088.61 more copy please?DPDMAI::CLEVELANDFri Jan 06 1989 10:235
    If possible, I would sure like a copy of the article as well!
    Have fun at the Boat Show!
    
    Robert Cleveland M/S DLO.

1088.7Info on its way...CHEFS::GOUGHPPete Gough @REO 830-6603Wed Jan 18 1989 03:119
    Rick and Robert a copy of the Yachting Monthly evaluation of the
    prop plus a glossy picked up at the London Boat Show is on its way
    to you. On the stand they would not discuss prices for the US but
    I was quoted 350 pounds for my Moody plus VAT (15%). I wont be
    indulging especially as CIRCE goes quite well astern etc. I hope
    the info arrives this year I have put it in the internal post....
    
    Pete

1088.8tnx..DPDMAI::CLEVELANDGrounded on The RockWed Jan 18 1989 11:384
    Thanks Pete! 
    I'll be watching for it!
    Robert

1088.9PROP INFOPOLAR::HEWITTMon Jan 23 1989 10:389
    Thanks for the info, How about the show? Any other new and wonderful
    gadgets that every sailor can not do without?
    
    I will keep an eye out for the prop info in the mail.
    
    Thanks again
    
    Rick

1088.10Boat Shows are for dreaming.....CHEFS::GOUGHPPete Gough @REO 830-6603Tue Jan 24 1989 10:4720
    The London Show was a good mid winter fix........
    Swan had their new 36 footer on show nice at 85,000 pounds plus
    VAT (15percent). More reasonably but equally unafordable the new
    Moody 336. There is a new Autohelm out for wheel steering aimed
    at the 30-40 foot range and lower price etc than its predecessors.
    My neighbour at the marina was impressed enough to buy one to replace
    his 10 year old autopilot..... Fox's spice stand was doing a roring
    trade. (One stand where we made some purchases) A lot of talk about
    what happens to DECCA and LORAN when GPS gets off the ground, it
    seems the sets for GPS could be very expensive compared with DECCA
    or LORAN or SATNAV receivers today. It was as ever my day of
    dreams........... 
    
    Have those who I sent info on the prop got it yet?
    
    
    Pete	   
                                          
                                          

1088.11Has the mailman come?DPDMAI::CLEVELANDGrounded on The RockWed Jan 25 1989 09:519
    Not yet Pete, but I'm checking daily!
    
    By the way, have you noticed much difference in price in the used
    boat market overseas to what you see advertised in this file or
    american publications? I'm curious if pre-owned boats are less
    expensive in Europe and England.
    
    Robert

1088.12Cheaper your side of the pond I thinkCHEFS::GOUGHPPete Gough @REO 830-6603Thu Jan 26 1989 03:1517
    I believe that secondhand boats are a lot cheaper in the US than
    in continental Europe or the UK. I am also told by a US citizen
    currently living in the UK that prices for equipment are often cheaper
    in the US than the UK even for UK produced items.......
    
    Sample boat prices......1978 Westerly Pentland Ketch (31 feet) 20,000
    pounds. 
    			    1985 Moody 31 (31 feet) 35,000 pounds
    
   			    1986 Moody 346 (34.f feet) 44,000 pounds
    
    Depending on the current rate of exchange it still seems expensive
    compared with ad's in the US for say Pearsons which I guess are
    the US equivilent of Westerly or Moody.
    
    Pete

1088.13maybe not so badMSCSSE::BERENSAlan BerensThu Jan 26 1989 09:3232
re .12:

>>>    ...... that prices for equipment are often cheaper
>>>    in the US than the UK even for UK produced items.......
    
Well, there is the little matter of the 15% VAT that you pay and we in the 
(former) colonies don't pay. (No taxation without representation and all 
that, don't you know.)

>>>    Sample boat prices......1978 Westerly Pentland Ketch (31 feet) 20,000
>>>    pounds. 
>>>    			    1985 Moody 31 (31 feet) 35,000 pounds
>>>    
>>>   			    1986 Moody 346 (34.6 feet) 44,000 pounds
    
>>>    Depending on the current rate of exchange it still seems expensive
>>>    compared with ad's in the US for say Pearsons which I guess are
>>>    the US equivilent of Westerly or Moody.
    
Presumeably, the prices you quote are based on the original purchase 
price (including VAT). At $1.75 per pound sterling (about the current 
exchange rate), the Moody 346 would be about $65 000 (after subtracting 
the 15% VAT). That's not that much different than what a similar boat 
might cost here. Don't forget that getting a boat from the US to the UK 
might easily cost $10 000 (whether shipped as freight or sailed across). 

I don't know about ads in the UK, but here you can find a tremendous 
range of asking prices for very similar boats, a range that runs from 
foolishly optimistic to painfully realistic. It is easy to find boats 
that have been for sale for months or years (see note 263.xxx for 
examples).

1088.14RECEIVED INFOPOLAR::HEWITTThu Jan 26 1989 12:5811
    PETE
    
    I finally received the information on the prop today. I looked it
    over quickly and it seems very interesting. I will have to get the
    details on my boat and forward them to the manufacturer for a price
    quote.                                                    
    
    Thanks again for the help, I was looking for this for quite a while.
    
    Rick

1088.15received info too..DPDMAI::CLEVELANDGrounded on The RockMon Jan 30 1989 10:167
    Pete,
    I too finally received my info! Looks really interesting! I want
    to sit down tonight and absorb it. Thanks for sending it, I really
    appreciate it.
    
    Robert