Outboards and sailboat balance question - SailNet Community
 4Likes
Reply
 
LinkBack Thread Tools
post #1 of 27 Old 06-21-2016 Thread Starter
Senior Member
 
Join Date: May 2014
Location: Bar Harbor, ME
Posts: 416
Thanks: 39
Thanked 8 Times in 8 Posts
Rep Power: 5
 
Outboards and sailboat balance question

Does having an outboard on a small sailboat unbalance the boat and cause pitching?

I was told in another place that having a 90 lb outboard on a 19 foot sailboat would unbalance the boat and cause pitching and hobby horse actions.

I have not noticed this with a 60 pounder and two people at the stern in the cockpit, but again I don't tend to sail in conditions where the wave heights are high enough to cause pitching because my only sailing partner is the admiral, and conditions like that scare her.

Can this be balanced by adding movable ballast forward to the center post or to the bow, or by hiring a 65 pound kid to move around inside the cabin?
Zarathu is offline  
Sponsored Links
Advertisement
 
post #2 of 27 Old 06-21-2016
One of None
 
deniseO30's Avatar
 
Join Date: Nov 2006
Location: Bristol pa
Posts: 7,932
Thanks: 72
Thanked 188 Times in 176 Posts
Rep Power: 14
   
Re: Outboards and sailboat balance question

Most sailboats have what is called a "displacement Hull"
the more horsepower used to push the boat the more it will "squat" in the water and not really go faster 19ft boat probably only needs 3- 5 HP and guessing the 90lbs is 9 or 10 HP? Which will make the transom"sink" when the extra HP pushes the boat against its hull speed. When sailing, I doubt you will notice much if you aren't racing or into performance sailing. You do want to be mindful of the boats "freeboard". Since the o/b is like another person's weight
Zarathu likes this.

"Next best thing to not having a boat? The knowledge from having one!" Denise, Bristol PA, On Tidal Delaware River, Anchor Yacht Club.
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

My last project!
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
deniseO30 is offline  
post #3 of 27 Old 06-21-2016
Senior Member
 
Join Date: Oct 2000
Location: Portland, OR
Posts: 1,077
Thanks: 3
Thanked 48 Times in 47 Posts
Rep Power: 19
 
Re: Outboards and sailboat balance question

The boat's NA designed the boat for XX number of pounds of aux. engine. The hull displacement took this into account, whether it's an inboard engine or an OB mounted on the transom.
Lots of smaller sailboats had the weight of an OB factored in to their displacement calculation, whether planned to be on the transom or in a well.

I have only seen one 19' sailboat with a large OB, and that was about 40-ish hp. This was an early model MacGregor motor sailer, prior to their 26 footer.

What kind of boat are you looking at?

Loren
olson34 is online now  
 
post #4 of 27 Old 06-21-2016 Thread Starter
Senior Member
 
Join Date: May 2014
Location: Bar Harbor, ME
Posts: 416
Thanks: 39
Thanked 8 Times in 8 Posts
Rep Power: 5
 
Re: Outboards and sailboat balance question

Quote:
Originally Posted by deniseO30 View Post
Most sailboats have what is called a "displacement Hull"
the more horsepower used to push the boat the more it will "squat" in the water and not really go faster 19ft boat probably only needs 3- 5 HP and guessing the 90lbs is 9 or 10 HP? Which will make the transom"sink" when the extra HP pushes the boat against its hull speed. When sailing, I doubt you will notice much if you aren't racing or into performance sailing. You do want to be mindful of the boats "freeboard". Since the o/b is like another person's weight
That's what I figured. The 90 lbs is a 6 hp 60 lb Tohatsu Plus a 30 lb Torqeedo 1003. Each used for different things. The tohatsu is needed when I need to run back to the beach launch, often through rough seas, pulling a 10 foot walker bay dinghy, or for running back to the mooring from an approaching storm when I need to do hull speed, or hiking out long distances in a short time period, or motoring at night back from the fireworks trying to avoid a dense field of lobster pots.

The torqeedo is for anything else(getting out to better wind, coming into the mooring or dock, or just quiet motoring to get somewhere when I'm not in a hurry, and as "kicker" back up for when the gas engine decides to fail---as I have experienced int he past in dangerous circumstances.

I have a huge 24 inch freeboard, and the boat sails best and fastest in not more than 5-10 degree heel.

Thanks for your help. You confirmed my thoughts.
Zarathu is offline  
post #5 of 27 Old 06-21-2016 Thread Starter
Senior Member
 
Join Date: May 2014
Location: Bar Harbor, ME
Posts: 416
Thanks: 39
Thanked 8 Times in 8 Posts
Rep Power: 5
 
Re: Outboards and sailboat balance question

Quote:
Originally Posted by olson34 View Post

What kind of boat are you looking at?

Loren
See my answer to Denise. I've not noticed hobbyhorse pitching with only the 60 pound previous Honda and three people in the cockpit. I tend not to be sailing when the weather gets difficult, and unless I got caught, the biggest waves I get are about 18 inches, not really enough for hobbyhorse pitching. But I can move ballast to midships to balance if necessary.

Last edited by Faster; 06-21-2016 at 01:53 PM. Reason: fixed quote
Zarathu is offline  
post #6 of 27 Old 06-21-2016
One of None
 
deniseO30's Avatar
 
Join Date: Nov 2006
Location: Bristol pa
Posts: 7,932
Thanks: 72
Thanked 188 Times in 176 Posts
Rep Power: 14
   
Re: Outboards and sailboat balance question

this helps
https://youtu.be/Ip5FDBjgdj0

"Next best thing to not having a boat? The knowledge from having one!" Denise, Bristol PA, On Tidal Delaware River, Anchor Yacht Club.
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

My last project!
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
deniseO30 is offline  
post #7 of 27 Old 06-21-2016 Thread Starter
Senior Member
 
Join Date: May 2014
Location: Bar Harbor, ME
Posts: 416
Thanks: 39
Thanked 8 Times in 8 Posts
Rep Power: 5
 
Re: Outboards and sailboat balance question

Quote:
Originally Posted by deniseO30 View Post
Yeah it looks like a miniature CG boat. We have someone in the WWP19 who put a 40 hp OB on the stern and it will plane and do about 35 MPH.
Zarathu is offline  
post #8 of 27 Old 06-21-2016
Doesn't sail enough
 
zedboy's Avatar
 
Join Date: Jul 2010
Location: Eastern Med
Posts: 616
Thanks: 10
Thanked 31 Times in 31 Posts
Rep Power: 9
 
Re: Outboards and sailboat balance question

I had a 10HP 2-stroke Mariner that probably weighed 50-60lb on my Siren 17. Never felt it caused balance issues - don't see why it would, considering it was right off a square transom and 150+lb adults sat right next to it (on a boat that weighs 750lb dry, just over half a WWP 19!).

It was far more horsepower than needed for hull speed. The Siren will plane (or close) but the rudder became impossible at high speeds due to prop wash.
Zarathu likes this.
zedboy is offline  
post #9 of 27 Old 06-21-2016
Senior Member
 
Join Date: Dec 2014
Posts: 898
Thanks: 15
Thanked 72 Times in 71 Posts
Rep Power: 5
 
Re: Outboards and sailboat balance question

Weight in the ends has an insidious effect on the boat. Its symptoms are not obvious. The best advice is to do what you can to keep weight out of the ends. If you need motors aft and perhaps an anchor with chain ready at the bow, so be it. Just know you have seriously degraded your sailing performance. The only way to demonstrate it is to one day remove all the heavy gear fore and aft then go for a sail. Or just sit on anchor with waves running. The difference is usually significant. That is why racers do what they can to avoid any extra weight in the ends. All these little things add up. Does it make a difference? Certainly. Do you care? Perhaps not.

OP asked if the weight aft might be compesated for with weight elsewhere. No it cannot. The weight needs to be either removed from the boat or moved towards the center. Fuel tanks and batteries might be moved. Crew can sit more forward.
Zarathu likes this.

"...there are two kinds of opinions, those based upon tradition ... and those having something in their favor." B. Russell
aloof is offline  
post #10 of 27 Old 06-21-2016 Thread Starter
Senior Member
 
Join Date: May 2014
Location: Bar Harbor, ME
Posts: 416
Thanks: 39
Thanked 8 Times in 8 Posts
Rep Power: 5
 
Re: Outboards and sailboat balance question

Quote:
Originally Posted by aloof View Post
That is why racers do what they can to avoid any extra weight in the ends. All these little things add up. Does it make a difference? Certainly. Do you care? Perhaps not.
Everyone who was complaining about this in a West Wight Potter was talking about degraded performance. That's kind of ridiculous in a boat whose top speed is about 5.5 knots, so that its degraded to 4 knts. Big deal. People who buy WWP19's didn't buy them for speed, they bought them for stability and the pocket cruising. And they generally(unless the sail in the really choppy San Francisco Bay) don't sail in enough chop to be worried about hobby horsing, because in those conditions they are either reefed a lot, or they are actually using the big engine that they have hanging off the stern starboard.

Racers don't own west wight potters in the first place.
Zarathu is offline  
Reply

Quick Reply
Message:
Options

By choosing to post the reply above you agree to the rules you agreed to when joining Sailnet.
Click Here to view those rules.

Register Now



In order to be able to post messages on the SailNet Community forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
Please note: After entering 3 characters a list of Usernames already in use will appear and the list will disappear once a valid Username is entered.


User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in











Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Similar Threads
Thread Thread Starter Forum Replies Last Post
The balance point davidpm Boat Review and Purchase Forum 11 12-29-2012 05:14 PM
A question about balance YamasSea Learning to Sail 6 06-04-2010 10:26 PM
Load Balance ... MSN2Travelers Racing 10 10-20-2009 02:20 PM
Outboards for sailboat rbh1515 General Discussion (sailing related) 27 06-09-2001 07:10 PM
Outboards for sailboat rbh1515 Gear & Maintenance 4 03-20-2001 04:02 AM

Posting Rules  
You may post new threads
You may 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 On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome