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 Author  Topic: ELCO and HIggins Planing Speed and Trim Angle
  Jerry Gilmartin

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Post a Reply To This Topic    Reply With Quotes     Edit Message     View Profile of Jerry Gilmartin   Send Email To Jerry Gilmartin Posted on: Jan 15, 2014 - 2:03pm
Hi Andy,
I will look to see if I can find one.

Jerry Gilmartin
PT658 Crewman
Portland OR

Total Posts: 1469 | Joined: Oct 8, 2006 - 11:16pm | IP Logged

Roy Forbes

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Post a Reply To This Topic    Reply With Quotes     Edit Message     View Profile of Roy Forbes  Posted on: Jan 19, 2014 - 7:30am
That is pretty cool Jerry,
Could you tell me how fast I need the 623 to be going before she gets up on plane running 2 engines with two 3 blade 2" props ?


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  Jerry Gilmartin

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Post a Reply To This Topic    Reply With Quotes     Edit Message     View Profile of Jerry Gilmartin   Send Email To Jerry Gilmartin Posted on: Jan 19, 2014 - 11:03am
Hi Roy,
Yes uh, according to my calculations the 623 must be moving at least 4 knots to get up on the plane. Thanks Jerry

Jerry Gilmartin
PT658 Crewman
Portland OR

Total Posts: 1469 | Joined: Oct 8, 2006 - 11:16pm | IP Logged

  Jerry Gilmartin

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Post a Reply To This Topic    Reply With Quotes     Edit Message     View Profile of Jerry Gilmartin   Send Email To Jerry Gilmartin Posted on: Jan 20, 2014 - 1:12pm
Hi Andy,
I wanted to post this here as well as email you so the board can see what we are talking about. Note that the testing stopped at 2500 rpm/43 knots. In talking to several veterans, I was told that the crews would operate these engines at higher rpm's than 2500, if you continue the curve to lets say 3300 what would you see for speed? (BTW The overspeed limiter would have to be made inoperative before exceeding 2950 rpm) Jerry

Speed vs RPM graph from testing on PT625



Jerry Gilmartin
PT658 Crewman
Portland OR

Total Posts: 1469 | Joined: Oct 8, 2006 - 11:16pm | IP Logged

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: Aug 10, 2014 - 6:22am
I ran across this Andy and thought of you:

Title : COMPARATIVE RESISTANCE DATA FOR FOUR PLANING BOAT DESIGNS
Report Date : JAN 1957

Abstract : Four existing models of planing craft were retested at the Taylor Model Basin's standard condition for planing boat models. The test results for each model are presented in a design data sheet. The data are compared to show the effects of differences in hull form. These comparisons are independent of differences in hull loading, in LCG location, or in size of boat. Auxiliary graphs are included to assist in making estimates of speed and power for new designs.


Here's the link for a link to a .pdf: http://oai.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identifier=AD0145074. They used models of Elco and Higgins boats to collect data.


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Andy Small

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Post a Reply To This Topic    Reply With Quotes     Edit Message     View Profile of Andy Small  Posted on: Aug 11, 2014 - 9:29pm
Thanks Jeff. This is great info and will keep me busy with the analysis. Looks like the first is an early American design something like a PT8, the second a 70' Elco, the third a Higgins and the fourth a 80' Elco. Too bad they didn't have a hull form other than these pre-war designs since design practice was far more advanced by 57 (Tjeld/Nasty Class for example). I wonder if David Taylor did any Nasty Class tests that are sitting somewhere.

Thanks Again!


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  Andy Small

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Post a Reply To This Topic    Reply With Quotes     Edit Message     View Profile of Andy Small  Posted on: Aug 12, 2014 - 6:10pm
Bummer, Figure 10 is missing from the planing boat design document.


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