Reply
 
Thread Tools Display Modes
 
Old 07-14-2015, 02:54 PM   #61
Guru
 
Tad Roberts's Avatar
 
City: Flattop Islands
Country: Canada
Vessel Name: Blackfish
Vessel Model: custom
Join Date: Dec 2012
Posts: 707
One simple rule of thumb is "One installed HP for every 500 pounds of displacement will give hull speed." That's for average boats with B/L around 3 and D/L's of 260-400. And hull speed in this case will be a speed/length ratio of 1.34.

A long time ago Jay Benford designed a 35' double-ender for Ernie Gann, a boat called Strumpet. It wasn't too fat (beam 12'4") or heavy (disp 24,600 lbs - D/L = 335). They installed a huge engine, a 98 HP (at 2500 RPM) six-cylinder Ford with 2.9:1 reduction. They thought they had something special when they found she would happily run up to 8.57 knots, a S/L of 1.52. It turns out they just installed about twice the required HP. She would run at S/L 1.33, 7.5 knots, at 1800 RPM producing something less than 50HP.

The little TimberCoast Troller at 3500 pounds will run up to a S/L of 1.7, a double-ended displacement hull. This is accomplished by installing 3-4 times the required HP.
__________________
Advertisement

Tad Roberts is offline   Reply With Quote
Old 07-17-2015, 06:57 AM   #62
FF
Guru
 
FF's Avatar
 
Join Date: Oct 2007
Posts: 16,537
These guys are fighting 2 battles.

The usual double ender is very speed limited compared to a transom stern.

At speed they must have had a mountain of water astern!
__________________

FF is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off





All times are GMT -5. The time now is 01:43 PM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2006 - 2012