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 Author  Topic: Question for PT Boat Experts
victorkchun

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Post a Reply To This Topic    Reply With Quotes     Edit Message   Posted on: Dec 25, 2008 - 4:32pm
I have enclosed two pictures with some sort of "fins" on the side of the boat. One picture show a pt boat with the "fins" on and the other it seems they took them off but they were there. Can anyone tell me what they are? And what they are used for? Thanks



The previous photo in this place was substituted for a smaller version to be more down-loading friendly, - To see original full size image click here:
http://s130.photobucket.com/albums/p249/ptboats/Victor%20Chun/?action=view¤t=ptboatfin2.jpg





The previous photo in this place was substituted for a smaller version to be more down-loading friendly, - To see original full size image click here:
http://s130.photobucket.com/albums/p249/ptboats/Victor%20Chun/?action=view¤t=ptboatfin1.jpg


Victor K Chun

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QM

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Post a Reply To This Topic    Reply With Quotes     Edit Message   Posted on: Dec 25, 2008 - 5:42pm
I will try a wild guess. First, the pictures appear to be two different boats. If I am identifying what is referred to as fins, it may be a variation of part of the cradles supporting the boats.

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SouthWestPacificPT

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Post a Reply To This Topic    Reply With Quotes     Edit Message   Posted on: Dec 25, 2008 - 5:52pm
I read that was called the Elco Step.


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David Buck

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Post a Reply To This Topic    Reply With Quotes     Edit Message     View Profile of David Buck   Send Email To David Buck Posted on: Dec 26, 2008 - 4:17am
Hi Victor, I see that in your first photo there are six vanes or fences attatched to the side of the boat, did you also note that there appears to be a corresponding angle fittered to the underside as well ? It is of interest to see a fixed form of the Elco slipper fitted to the rear of the boat with another angled plate fitted to it to. This plate has been fitted over the rudders with large cutouts to allow the rudders to turn. The chine also shows reinforcement that goes all the way to the end of the slipper

I use the term Slipper as i have your book and am looking at it on page 82 and this term fits.

In your second photo the side vanes are gone but the rest remain the boats do look differant but the lower one looks to have been in the water a little longer than the first. The lower photo also shows the added items better and is a clearer photo.However i would think that the reason the side vanes are missing is not that they have been taken of rather the boat has removed them due to high speed and manoeuvrs.

Now to what they may be, knowing that Elco tried various ways to increase the boats speed i would suggest they are an attempt at that.



D.buck

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  TED WALTHER

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Post a Reply To This Topic    Reply With Quotes     Edit Message     View Profile of TED WALTHER   Send Email To TED WALTHER Posted on: Dec 26, 2008 - 7:33am
Victor;
The top photo is PT 562 RON 29( notice chalk marking on cradle portion aft, "PT 562"). The bottom photo is of PT 487 RON 4( notice numbers on engineroom hatch, even though cradle is marked PT 562). Both these photos were taken around December 16, 1943. The photos were taken at ELCO. In the 487 photo look closer, the "steps on the side are not removed, thats how the look from the rear port quarter.
With this installed PT 487 was clocked at 55.95 knots(almost 65 MPH) with a light load and 53.62 knots with full warload.
The six steps are installed port and starboard and the plane is on the stern. I am just guessing but on Giant Killers you see a boat in Bayonne Bay from an aerial film shot turn around at high speed, I would be willing to bet that is 487 with this installed, the boat was recorded at high speed turn and reversing course in 6 seconds.
In the PT 562 photo the boats of RON 29 were painted in measure 31/5P for thier shakedown period. Then painted Thayer Blue for deployment to Med.
Anyway this was installed on PT 560-563 of RON 29 and the 4 boats ran fromm New York to Miami. This test run showed 25% more fuel was used, 75% more lubricating oil was used at cruising speeds. In heavy seas the boats rooted in heavy seas, steering was lousy, and acceleration dropped. The steps warpped and the brackets became loose and cracked, the boats also became sensitive to added weights. In other words this worked great in calm seas only. See page 78 in "AT CLOSE QUARTERS".
Take care,
TED


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TGConnelly

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Post a Reply To This Topic    Reply With Quotes     Edit Message   Posted on: Dec 26, 2008 - 7:44am
Or, could it be something that Elco used to stabilize the hulls when they flipped them right side up after being upside down during the construction and they hadn't been removed yet?

Just thinking outloud ...




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  TED WALTHER

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Post a Reply To This Topic    Reply With Quotes     Edit Message     View Profile of TED WALTHER   Send Email To TED WALTHER Posted on: Dec 26, 2008 - 8:20am
Nope, it is the ELCOPLANE.
take care,
TED


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David Waples

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Post a Reply To This Topic    Reply With Quotes     Edit Message     View Profile of David Waples  Posted on: Dec 26, 2008 - 8:37am
There's some nice detail of the "stabilizers" attached to the cradel as well for Frank's crane project.

Very interesting photos Victor. Thanks for sharing.
Dave

David Waples

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Jeff D

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Post a Reply To This Topic    Reply With Quotes     Edit Message     View Profile of Jeff D   Send Email To Jeff D Posted on: Dec 26, 2008 - 8:55pm
I don't think they're gone in the 2nd photo, just a trick of the photo's exposure. Looking at the chine you can see them.

My inexpert, total guess is vents that possibly lead to the ends of the steps, maybe to introduce air behind the steps/under the hull to reduce drag.

The stepped hull vee is not dead, check out this sexy babe:
http://www.floridamariner.com/wcms/content/134.php



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Frank J Andruss Sr

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Post a Reply To This Topic    Reply With Quotes     Edit Message     View Profile of Frank J Andruss Sr   Send Email To Frank J Andruss Sr Posted on: Dec 27, 2008 - 12:10am
Ted is correct. This was the six step process that was the ELCO PLANE, a trial of attached steps on bothe sides of the Hull. This trial made for an incredible increase in speed, but the boat handled sloppy at those speeds, and the increase in lube consumption and fuel was a disaster, not to mention the steps rotting off the boat or breaking off. It was dis-continued............


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