Go Back  The Hull Truth - Boating and Fishing Forum > BOATING FORUMS > The Boating Forum
Reload this Page >

Twin Outboards? Single engine performance?

Notices
The Boating Forum

Twin Outboards? Single engine performance?

Old 04-10-2019, 01:09 PM
  #1  
Junior Member
Thread Starter
 
Join Date: Jan 2005
Location: Anchorage AK
Posts: 15
Likes: 0
Received 1 Like on 1 Post
Default Twin Outboards? Single engine performance?

Simple question, will your boat plane on one engine?

Please give a short description of your vessel.

I am currently repowering an I/O twin 26 foot to outboards on a bracket and want to learn all I can to prevent mistakes. My boat is a 26'x 8.5' Olympic which is half deck, half cabin, weighs 4500-5500lbs currently. Volvos made 290 hp when new and am thinking of twin 150s which I question whether or not I can get on step. There is no chance of planing with the drag created by a dead outdrive but being able to raise an outboard out of the water just might do it. I have seen similar hulls with a single 225.
Old 04-10-2019, 01:24 PM
  #2  
Senior Member
 
Join Date: Jan 2007
Location: NSW Australia
Posts: 7,529
Received 2,318 Likes on 1,293 Posts
Default

Most wont plane on a single engine, unless big engines are fitted, put simply, you have two engines equaling (say) 500HP, the motors are propped for that HP, you stop one motor, and your motor now needs a prop to suit 250HP, but it's grossly over propped and can't supply the power to turn the much bigger prop, however, sometimes, when big motors are used, say, 350s giving a total of 700HP on the same boat, one 350 can at times overcome the big prop and plane the boat, it's not just black and white, there's a lot to consider.
Old 04-10-2019, 02:05 PM
  #3  
Senior Member
 
Join Date: Feb 2007
Location: Texas
Posts: 1,066
Received 927 Likes on 411 Posts
Default

I sense a 2 stroke / E-Tec comment coming up.
Old 04-10-2019, 02:12 PM
  #4  
Admirals Club Admiral's Club Member
 
Join Date: Apr 2008
Location: Annapolis, MD
Posts: 1,093
Received 408 Likes on 213 Posts
Default

I have a 25' classic whaler with whalerdrive (26'7" LOA, 8' beam), and twin 250 ox66's. 6300 lbs wet loaded lightly. Easily planes off on a single, and I can hit 5,000 RMP's/42 MPH even with the over propped condition. Prior to the 250's, I had 225's and hit 4,600 rpm/38MPH. With 150 4 strokes...that's gonna be tough.
Old 04-10-2019, 02:23 PM
  #5  
Senior Member
 
Join Date: Sep 2012
Location: Bonita Springs, Florida
Posts: 977
Received 624 Likes on 365 Posts
Default

I have a 1999 Pursuit 28 foot center console with twin 225 Ox66's and with 21" props I can not plane with one engine, but I can with my 19" props. lost a little speed but gained a piece of mind. I can get up to 32 mph on one engine.
Old 04-10-2019, 06:27 PM
  #6  
Senior Member
 
Join Date: Jul 2017
Posts: 567
Likes: 0
Received 179 Likes on 102 Posts
Default

That one engine can suffer long term or catastrophic damage if run for very long with the huge overload from the twin engine prop load. If your way overpowered maybe not. If your hard pressed to run on plane with one engine maybe so.
Old 04-10-2019, 06:44 PM
  #7  
Admirals Club Admiral's Club Member
 
Join Date: Dec 2014
Location: Dacula Ga
Posts: 188
Received 81 Likes on 31 Posts
Default

27’ cc with twin 200’s, yes it will plane a fishing load with one engine.
Old 04-10-2019, 06:52 PM
  #8  
Senior Member
 
Join Date: Feb 2001
Location: Australia
Posts: 3,635
Received 91 Likes on 67 Posts
Default

With even the correct power match you would definitely have to prop permanently for ever such an event occurred, if ever, that is if you do expect to race home on 1 engine. Propping twins for a maybe single engine scenario is then probably going to go against your expectation to keep up with similar setups. There's nothing up front with this one and trying to change a prop at sea is not the best idea. Just be happy to get home on one, might not be a fast trip but it at least gets you home without throttling an engine
Old 04-10-2019, 07:56 PM
  #9  
Senior Member
 
Join Date: Feb 2009
Posts: 1,700
Received 581 Likes on 278 Posts
Default

Nope, but it will get you home at 8 knots on one. That's why I have two.
Old 04-10-2019, 08:10 PM
  #10  
Senior Member
 
Join Date: Apr 2015
Posts: 202
Received 43 Likes on 21 Posts
Default

I have a 26’ Paramount with twin 225 optis. It will plane off and run in the upper 30’s with one engine and the other tilted up. 4000 lbs dry hull about half tank of gas (80 gal) and 4 people.
Old 04-10-2019, 08:21 PM
  #11  
Junior Member
Thread Starter
 
Join Date: Jan 2005
Location: Anchorage AK
Posts: 15
Likes: 0
Received 1 Like on 1 Post
Default

Originally Posted by IPA1 View Post
That one engine can suffer long term or catastrophic damage if run for very long with the huge overload from the twin engine prop load. If your way overpowered maybe not. If your hard pressed to run on plane with one engine maybe so.
Only reason to run single is if I lost power in the other.I wouldn't run any motor at full throttle unless it was an emergency, I was hoping for a 23 to 25 mph cruise on one with a couple of hundred rpm cushion While I am typically no more than 40 miles from port with new power I may push that to 100 or make Sound crossings or round the Peninsula which might be 125 to 150 miles. I would like a 50% reserve margin for fuel but I have alternate ports or safe grounds for anchoring within 20 miles most of the time except out of Seward. If the water is nice I don't mind plodding along at 7 or 8 mph.
Old 04-10-2019, 08:44 PM
  #12  
Senior Member
 
Join Date: Sep 2005
Location: Basking Ridge/Mantoloking
Posts: 354
Received 19 Likes on 12 Posts
Default

Our 261 Mako with 200 HPDIs will get up and run 25 or so on one with three people and 1/2 + fuel load.

Unfortunately, I got to find out. I don't think its advisable for long distances, the engine is reeeealy lugging.
Old 04-10-2019, 08:48 PM
  #13  
Senior MemberCaptains Club Member
 
Join Date: Mar 2002
Location: Pensacola, FL
Posts: 5,534
Received 384 Likes on 254 Posts
Default

Originally Posted by tmd11111 View Post
I sense a 2 stroke / E-Tec comment coming up.
My 26 footer won't plane on a single 200HP four stroke...but when I had twin 250 Etecs, it still wouldn't plane on one!
Likes:
Old 04-10-2019, 09:09 PM
  #14  
Senior Member
 
Join Date: May 2018
Posts: 282
Received 118 Likes on 68 Posts
Default

Nope not even close to planing on one. Just gonna have to settle in for a nice long cocktail cruise back if one fails, trolling and watching bottom for new spots the whole way in.
Likes:
Old 04-10-2019, 09:42 PM
  #15  
Senior Member
 
Join Date: Jul 2012
Posts: 726
Received 247 Likes on 124 Posts
Default

Previous 2 boats: 25ft Grady white sailfish with twin Honda 150s and 30ft Grady white marlin with twin Suzuki 250s. Sailfish not even close to planing on one. The marlin might barely if I distributed weight and trimmed just right but it’s a terrible idea unless you’re being chased by pirates.
Old 04-10-2019, 10:56 PM
  #16  
Admirals Club Admiral's Club Member
 
Join Date: Apr 2017
Location: Mount Dora, Florida
Posts: 133
Received 31 Likes on 20 Posts
Default

Mine gets on plane with one outboard, runs 43 mph @ 5k. I've had to complete an offshore trip in flamingo mode once. Boat ran like a champ.
Old 04-10-2019, 11:25 PM
  #17  
Senior Member
 
Join Date: Aug 2015
Location: Southern Ocean
Posts: 661
Received 113 Likes on 58 Posts
Default

Mine will do over 40mph with one engine tilted.

High 20s cruise home comfortably one down if I ever had to.

Beats hell out of relying on getting home at kicker speed or displacement speed one of the mains with the distances I often travel

2xf300s on 23ft tinny.
Old 04-11-2019, 03:48 AM
  #18  
Senior Member
 
Join Date: Feb 2015
Location: Chesapeake, VA
Posts: 1,624
Received 173 Likes on 99 Posts
Default

my boat a proline 2950 cant plane on a single 250G2. I know that because someone accidentally hit the kill button shutting down an engine while i was trying to get on plane one day.
Old 04-11-2019, 07:46 AM
  #19  
Senior Member
 
Join Date: May 2010
Location: Costa Rica and Sardinia (Italy)
Posts: 2,333
Received 169 Likes on 144 Posts
Default

Boston Whaler Outrage 23 with twin F150 will plane after minutes and all guests sittin at the bow
Venture 34 with twin DF300AP will not plane
Both with one engine tilted out of the water

There are some boats they will plane, some not as most of them are propped to plane with 2 engines, not one.
All weight forward will help to get to plane with onyl one engine.

However, you most likely will break the engine or spin the propeller if you plane for a longer period with only one engine working

Chris
Old 04-11-2019, 07:56 AM
  #20  
Senior MemberCaptains Club Member
 
Join Date: Nov 2003
Location: Gulf Breeze, FL
Posts: 4,058
Likes: 0
Received 537 Likes on 178 Posts
Default

It is very boat dependent, but I’m a huge fan of making 8 knots and having plenty of fuel to get back in the case of an engine failure.
Likes:

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -

Copyright © 2021 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.