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 Author  Topic: Elco at flank speed
Phil

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Post a Reply To This Topic    Reply With Quotes     Edit Message     View Profile of Phil  Posted on: Aug 12, 2021 - 9:02pm
How long could an 80’ Elco run at flank speed before it had to be slowed down?


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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: Aug 13, 2021 - 1:57am
Hi Phil,
It was not a matter of having to slow down as much as the amount of gasoline they carried and how much they used at top speed. I have read that the top speed on 3 engines uses about 450 gallons per hour. The boats would carry 3000 gallons of gas on board. 3000 divided by 450 gallons per hour is around 6.5 hours max possible time at top speed.. But that will only get you around 280 miles if you are moving at 42knots. So the boats would go more economical speeds to get on station and then race back to port at the end of the patrol.

Jerry

Jerry Gilmartin
PT658 Crewman
Portland OR

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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: Aug 13, 2021 - 2:15am
Here is a chart from a Higgins that shows the principal. Also the High speed cruising test data where they ran PT625 for 1 hour at 2000 rpm on Port Forward tank used 390 gallons and then at 2400 rpm for one hour using gas from Stbd fwd tank (475 gallons used)


Graph shows number of engine in use, rpms vs speed in knots, note that the graph stops at 22 knots when on 2 engines only and 9.5 knots when running only 1 engine since the engine cannot physically move the boat any faster when all 3 not running.

jUfPt.jpg


High Speed run trials fuel tank soundings showing fuel usage

jUHmw.jpg

Jerry Gilmartin
PT658 Crewman
Portland OR

Total Posts: 1311 | Joined: Oct 8, 2006 - 11:16pm | IP Logged

Phil

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Post a Reply To This Topic    Reply With Quotes     Edit Message     View Profile of Phil  Posted on: Aug 16, 2021 - 4:36pm
Thanks Jerry! You are the MAN! A guy on Facebook asked today if the prop shafts had joints for alignment on the Higgins?


Total Posts: 23 | Joined: May 19, 2021 - 10:52am | IP Logged


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