Conference vicki::boats

    I agree they seem to have disappeared. From what i heard,
    they were not good when backing down. Not enough prop in the
    water.
    
    Speaking of tunnel drive, I understand the new 34 silverton's
    prop's have less of an angle to the water, than 88 and earlier
    models. In a discussion with a fellow boater, there is one at
    his marina, he was telling me that the owner has a hell of a 
    time getting into his slip, with any wind or current. He's all
    over hell, makes no difference if you put power to it or not.
    
    Could be the reason Penn Yann tunnel drives disappeared.
    
    Oh, on the new Silverton, "it goes like hell in forward"
    so i'm told.
    
    Sorry to stray, but i thought it was worth mentioning.
    
    Jim (who likes to wander all over the docks and shoot the breeze.)
    

    Reg.........
    
    Still see several around the Wareham area.  Never owned one (always
    had outboards or I/O's), but observation tells me they must be
    inefficient at relatively low speeds.  AT less than half throttle
    they all seem to throw mountains of foam, at what appears to be
    a relatively high RPM for the speed.  Almost seems to be the result of 
    partial cavitation.  Appears that from 1/2 --> WOT they might be ok.  
    I wonder how "reverse" works?
    
    Doesn't look like they caught on.  The ones I see are all older
    boats, haven't seen any new ones.  Also never saw a tunnel drive
    except for Penn Yan.
    
    I'd stick with the outboard or I/O with power trim.... best of both
    worlds.
    
    (Given the above, I'm sure this will probably be debated by a satified 
    owner somewhere)  
    

    Hi Reg
    The reason that you only see the "Tunnel Drive" configuration on Penn
    Yann is that the designer patented the rights of the design a while ago
    and penn yann bought the rights exclusivly. It has gone thru 2 court
    battles and  appeals to be designated no- exclusive but Penn Yann keeps
    winning. I'm not sure if the PY boats are still in production but the
    retain ownership of the design.
    
    You will find a Very Limited production run of the layout from I belive
    it was Searay and another Fla. Co. They made something like 6 to 10
    boats before they had an injunction against them.
    
    They concept is good for protection and more efficent forward thrust.
    Need I say that in reverse they leave much to be desired. A bit more
    modern concept that may deserve a look is the surface drive made by
    Arnson,Karrma and others. It looks to be the best of both worlds. If
    you get to the boat shows take a look at the Black Fin 29. They are
    using the Arnson Drive on it.
    
    Of course if its running gear damage your worried about, you can always 
    set up a skid plate on the strut; or go with a full deadwood stype boat
    like the shamrock Inboard. Sharp looking 18 ft or 21 ft boats with 350
    chevys in them they make up to 31 ftrs.
    
                                           Walt
    
    Who really likes Inboards Too!
    

    Hello,
    
    I grew up in Ohio on Lake Erie, Western Basin - Catawba Island to be
    exact, and worked my through high school and college at 2 large marinas,
    Gem Boat Service and Fox Haven, over 8 years working experience.
    The PY was just about 1 of the worst boats I ever saw for many reasons
    and they are seen very much anymore because they simply didn't hold
    together. They were the only boat that shipped from the factory it
    was impossible to service the battery. You either had to tip the
    battery upside down or cut a hole through the deck to get it out for
    charging, winter storage or to check fluid levels. Tipping the battery
    upside spilled lots of battery acid on the vessel and this led to
    all the obvious problems. They never seemed to be able to take a
    beating without "loosening up". You can do alot better than a PY.
    
    -ck

    Bluewater yachts have a 41 and a 50 foot model that uses two tunnel
    drives. They are said to be very responsive in either direction.
    
    There is a 50 foot model on display most weekends at Newburyport.
    
    

    If any of you guy's/Gal's go to Bluewater Yachts. Ask for George
    Trabuchii and tell him Walt Gibson sent ya. You will get a better deal
    and I will get a kickback! Good for both of us!!
    
                                            Walt
    

    I have a Searay 268 with I/O. I stayed where we bought the boat
    so 90% of them are Searay's. It appears that the 30 ft up have a
    semi type tunnel design. I have never be on one but they seen to
    handle ok. The 1989 models at the marina also have the tunnel design.
    Any "Bigger Boy" Searay owner out there ?

    I notices the Bayliner 3288 has what appears to be a modified tunnel
    configuration. Anyone have one?
    
    Ray

re                      <<< Note 500.8 by KEEPER::THACKERAY >>>

>>    I notices the Bayliner 3288 has what appears to be a modified tunnel
>>    configuration. Anyone have one?
    
>>    Ray


	Brunswick probably owns Penn Yan by now anyway, so its no
surprise (-: 

	It seems the design is still around on the bigger boats, but 
not the smaller (~20 ft) ones.  I know that tugs and trawlers (and I 
think some large sail boats) have their props in tunnels, maybe some 
of the design trade offs change with larger boats ?????  Well, of 
course they do....  

	R

    Moved by moderator...
    
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Note 929.0                        Tunnel Drives                       No replies
EMDS::JEAN_SIMON                                      9 lines   8-NOV-1991 10:29
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        I am looking for information on tunnel drive boats. I will be 
     using the boat strictly trolling. I will not use it for skiing.
     Does anybody know pros and cons, performance, efficiency, and
     handling characteristic.
    
                                      Jim G.
    
        

    I have a Penn Yan tunnel drive boat. As many of the previous replies
    indicate backing up is  not strong. The boat basically backs up
    straight and you can't benefit from the prop walking the boat sideways
     into a dock. The boat can however be rotated almost within it own
    length by using reverse and forward alternately with the rudder turned
    fully to one side. The water flow is directed by the rudder similar
    to jet drives and reverse is used to counteract forward momentum.
    Wind and currents however affect this dramatically.
    
    The boat will troll quite well and runs straight at slow speeds
    provided you have the prop turning. With the prop not turning there is
    flow accross the rudder and the rudder is not below the hull to be
    affected by sideward drift.
    
    I have large trim tabs on the rear and do not experience the high RPM's
    to move the boat onto plane. Trim tabs should be on all Penn Yan
    tunnel drives for energy conservation reasons alone. Mine planes at
    2500 RPM where as the normal planning occurs at 3500 RPM. I hope this
    information is of help.
    
    
    Wayne