Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 19-08-2015, 09:44   #1
Registered User
 
Twill's Avatar

Join Date: Nov 2013
Location: Rainbow City Alabama
Boat: Ticon 30
Posts: 8
New Prop

I want to replace my prop on my Ticon 30 with a folding prop. It has a 2 blade on it at the moment. Will a 3 blade help my boat speed under power?
__________________

__________________
Twill
Twill is offline   Reply With Quote
Old 19-08-2015, 09:59   #2
Senior Cruiser
 
Cheechako's Avatar

Cruisers Forum Supporter

Join Date: Aug 2006
Location: Skagit City, WA
Posts: 19,365
Re: New Prop

a prop of proper size and pitch should get you to hull speed. If you are not getting there now you are not propped properly. A folding prop will likely be less efficient than your fixed 2 blade. (There may be some exceptions now days.) A feathering prop may be more efficient than your 2 blade.
__________________

__________________
"I spent most of my money on Booze, Broads and Boats. The rest I wasted" - Elmore Leonard











Cheechako is offline   Reply With Quote
Old 19-08-2015, 12:14   #3
Senior Cruiser

Cruisers Forum Supporter

Join Date: Mar 2014
Location: Anacortes
Boat: previous - Whitby 42 new - Goldenwave 44
Posts: 1,735
Re: New Prop

Read the other thread about folding versus feathering props and read the article about them by Yacht Monthly that is linked there. According to Flexofold, and the article backs this up, their two bladed prop can push the boat faster for a given rpm but the three bladed can give better acceleration and quicker stopping. Go figure.
__________________
exMaggieDrum is offline   Reply With Quote
Old 19-08-2015, 12:56   #4
Moderator
 
a64pilot's Avatar

Cruisers Forum Supporter

Join Date: Oct 2013
Location: Albany Ga.
Boat: Island Packet 38
Posts: 17,055
Re: New Prop

I know you can't always compare airplane and boat props, but in aircraft, the more the blades, the smoother the prop vibration wise, but also it's slower and less efficient.
More blades = more drag.
I think with very few exceptions, a feathering prop is actually a pretty inefficient prop, because it's blades are flat, no airfoil. You may can overcome this inefficiency by being able to precisely match the pitch to your boat as many are adjustable pitch wise, but it is an inherently inefficient blade profile.
__________________
a64pilot is offline   Reply With Quote
Old 19-08-2015, 14:01   #5
Senior Cruiser
 
Jim Cate's Avatar

Cruisers Forum Supporter

Join Date: May 2008
Location: cruising SW Pacific
Boat: Jon Sayer 1-off 46 ft fract rig sloop strip plank in W Red Cedar
Posts: 11,461
Re: New Prop

Quote:
Originally Posted by Cheechako View Post
a prop of proper size and pitch should get you to hull speed. If you are not getting there now you are not propped properly. A folding prop will likely be less efficient than your fixed 2 blade. (There may be some exceptions now days.) A feathering prop may be more efficient than your 2 blade.
Cheech, you have this quite backwards: a feathering prop is LESS efficient than either a folding or fixed prop (assuming decent design for all three types). this is inherently true due to the lack of twist in the feathering prop's blades. We've been over this effect many times here on CF... I'm surprised it keeps coming up.

Jim
__________________
Jim and Ann s/v Insatiable II , lying Port Cygnet, Tasmania once again
Jim Cate is online now   Reply With Quote
Old 20-08-2015, 10:55   #6
Registered User
 
Twill's Avatar

Join Date: Nov 2013
Location: Rainbow City Alabama
Boat: Ticon 30
Posts: 8
Re: New Prop

I would like to use a fixed prop. I don't really care about the slight lose of speed under sail. I need more speed under power. I can only get about 4 knots at the moment (5) with a clean bottom (maybe). The prop on my T30 is about 12 inches across. Will a three bladed prop give me another knot? or not...(ha ha). I do like the idea of smoother ride with the three blades. What is the best way to proceed? Thanks, you guys sure make this fun. I appreciate all the feed back.
__________________
Twill
Twill is offline   Reply With Quote
Old 20-08-2015, 11:02   #7
Registered User
 
leftbrainstuff's Avatar

Join Date: May 2011
Location: San Francisco and Australia
Boat: Liberty 458
Posts: 1,979
Re: New Prop

It would help if you can describe your current prop in terms of the technical specs.

Its not as simple,as just comparing props. There are tradeoffs. The system comprises hull, engine torque curve, drive reduction, prop specs and hull type and hydronamic dimensions.

Of course you can just try props as long as you're prepared for many haulouts and power tests.

If you're lucky enough to find someone with the exact combination you can learn from them.

Sent from my SM-N900T using Cruisers Sailing Forum mobile app
__________________
leftbrainstuff is offline   Reply With Quote
Old 20-08-2015, 11:03   #8
Marine Service Provider
 
fstbttms's Avatar

Cruisers Forum Supporter

Join Date: Oct 2006
Location: Under a boat, in a marina, in the San Francisco Bay
Posts: 3,594
Re: New Prop

Quote:
Originally Posted by leftbrainstuff View Post
Of course you can just try props as long as you're prepared for many haulouts and powerntests.
Why would you haul out simply to swap a prop?
__________________
fstbttms is offline   Reply With Quote
Old 20-08-2015, 11:05   #9
Registered User
 
leftbrainstuff's Avatar

Join Date: May 2011
Location: San Francisco and Australia
Boat: Liberty 458
Posts: 1,979
Re: New Prop

Quote:
Originally Posted by fstbttms View Post
Why would you haul out simply to swap a prop?
You can change props in the water if you like.

Sent from my SM-N900T using Cruisers Sailing Forum mobile app
__________________
leftbrainstuff is offline   Reply With Quote
Old 20-08-2015, 11:06   #10
Marine Service Provider
 
fstbttms's Avatar

Cruisers Forum Supporter

Join Date: Oct 2006
Location: Under a boat, in a marina, in the San Francisco Bay
Posts: 3,594
Re: New Prop

Quote:
Originally Posted by leftbrainstuff View Post
You can change props in the water if you like.
Yes, I know. I do it for a living. And I guarantee it is faster, cheaper and more convenient than hauling out to do it.
__________________
fstbttms is offline   Reply With Quote
Old 20-08-2015, 11:08   #11
Senior Cruiser
 
Cheechako's Avatar

Cruisers Forum Supporter

Join Date: Aug 2006
Location: Skagit City, WA
Posts: 19,365
Re: New Prop

Quote:
Originally Posted by Jim Cate View Post
Cheech, you have this quite backwards: a feathering prop is LESS efficient than either a folding or fixed prop (assuming decent design for all three types). this is inherently true due to the lack of twist in the feathering prop's blades. We've been over this effect many times here on CF... I'm surprised it keeps coming up.

Jim
It depends. The old Gori folding used on many racing boats were terrible and did not push the boat thru chop or work in reverse hardly at all.
A feathering Max Prop does both better than a fixed blade. The devil is in the details. You theory may be right but your reality isn't! just sayin....
__________________
"I spent most of my money on Booze, Broads and Boats. The rest I wasted" - Elmore Leonard











Cheechako is offline   Reply With Quote
Old 20-08-2015, 11:20   #12
Registered User
 
Twill's Avatar

Join Date: Nov 2013
Location: Rainbow City Alabama
Boat: Ticon 30
Posts: 8
Re: New Prop

I will be hauling out in the fall to do some other bottom work anyway> Can I get a consensus...Will a three blade make me faster ?? if not I will save myself the trouble and stay with the old prop. My boat is 9800 pounds a 4'11' fin and spade rudder. The prop shaft is old school one support strut. I have a slight vibration at moderate RPM very little at idle and very little at full power. My engine is a Yanmar 2 cylinder 16 hp. Thanks
__________________
Twill
Twill is offline   Reply With Quote
Old 20-08-2015, 11:31   #13
Registered User
 
deblen's Avatar

Join Date: Oct 2014
Location: Grand Manan,N.B.,Canada N44.40 W66.50
Boat: Mascot 28 pilothouse motorsailer 28ft
Posts: 1,400
Images: 1
Re: New Prop

Quote:
Originally Posted by Twill View Post
I would like to use a fixed prop. I don't really care about the slight lose of speed under sail. I need more speed under power. I can only get about 4 knots at the moment (5) with a clean bottom (maybe). The prop on my T30 is about 12 inches across. Will a three bladed prop give me another knot? or not...(ha ha). I do like the idea of smoother ride with the three blades. What is the best way to proceed? Thanks, you guys sure make this fun. I appreciate all the feed back.
A 3 blade will give you quicker acceleration & stopping/reversing.That is worth a lot in maneuvering.
Hull speed limits your top speed,unless you have more HP than the avg sailboat of similar length. You can push a knot or so beyond hull speed with enough HP,but you pay in fuel,etc.

My 28Ft pilothouse motorsailer has a hull speed of 6.2 kts. The sails will drive it that fast,with enough wind,etc,etc.
So would a 12-15HP diesel with 2 blade-the standard for 30 ft. sailboats.It would take awhile to reach hull speed,but it would get there.

I have 28HP 2.x reduction & 17D x 14P 3 blade & can reach 7.3kts at W.O.T., & get up there fairly quick.
Lots of squatting & extra fuel & the engine probably wouldn't last as long.
On the other hand,I can cruise at hull speed at 60% throttle/RPMs,so fuel consumption is excellent-1.5 Ltr/hr

It's a trade-off. 3 blades will cut your sailing speed by 1/2 + kts.,but you will be able to accelerate,dock,stop & maneuver with a lot more confidence.

If you go 3 blade,you will have to calculate a new dia. & pitch based on HP & reduction gear ratio.
Find a well respected prop shop & google for info/feedback on your boat model with 3 blade.

Cheers/Len
__________________
My personal experience & humble opinions-feel free to ignore both
deblen is offline   Reply With Quote
Old 20-08-2015, 11:36   #14
Registered User
 
Strait Shooter's Avatar

Join Date: Aug 2010
Location: Straits of Juan De Fuca
Boat: Ingrid
Posts: 786
Re: New Prop

Not likely to make you go faster.....quicker getting there, not faster though.

You will increase your range however.
__________________
"Waste your money and you’re only out of money, but waste your time and you’ve lost a part of your life.” (Michael Leboeuf)
Strait Shooter is offline   Reply With Quote
Old 20-08-2015, 11:37   #15
Registered User
 
Twill's Avatar

Join Date: Nov 2013
Location: Rainbow City Alabama
Boat: Ticon 30
Posts: 8
Re: New Prop

Thanks Len. I will consult the boatyard ..!!
__________________

__________________
Twill
Twill is offline   Reply With Quote
Reply

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

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


Similar Threads
Thread Thread Starter Forum Replies Last Post
Bought a Hyralign Prop. for I-37, Looking for Comments from Owners with this Prop. HighFly_27 Monohull Sailboats 6 28-04-2015 04:30
Prop walk depending on prop size? phipseml Propellers & Drive Systems 17 20-04-2015 08:06
Switching RH Prop For LH prop Triple Helix Engines and Propulsion Systems 4 19-05-2013 16:31
Prop Zinc Is Gone and Now I Have White Spots on the Prop dubhouse Propellers & Drive Systems 21 01-12-2010 14:59
Vari-prop vs. Max-prop winds aloft Product or Service Reviews & Evaluations 21 30-07-2008 11:22



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 18:51.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.