The Hull Truth - Boating and Fishing Forum

Go Back   >
Search


Reply
 
Thread Tools Search this Thread
Old 09-23-2006, 02:55 PM   #1
Senior MemberCaptains Club Member
Thread Starter
 
Join Date: Mar 2005
Location: Jupiter, FL
Posts: 518
Default adding dolphin to an outboard

does anyone have any input or experience adding a dolphin to an outboard?
the dophin is the big horizontal wing you can bolt on to the cavitation plate.
jlichterman is offline   Reply With Quote
Old 09-23-2006, 05:31 PM   #2
Senior MemberCaptains Club Member
 
Join Date: Jul 2006
Location: Pompano Beach, FL
Posts: 1,778
Default Re: adding dolphin to an outboard

I had one on my previous boat. It was a pursuit 2150 W/A, 1993. While the difference wasn't "amazing" it was certainly noticeable. It will give you a little bit of a quicker hole shot. Some people poo poo these things, but on the right boat, it's not a bad thing to put on. The only downside, as I recall, is that to install them, it requires that you drill into your lower unit, so once they're on, they're on.
rkatz is offline   Reply With Quote
Old 09-23-2006, 08:19 PM   #3
Senior MemberCaptains Club MemberPLEDGER
 
Join Date: May 2004
Location: Pensacola
Posts: 4,869
Default RE: adding dolphin to an outboard

Go down the main page here on THT and in the vendor forums, look for "permatrims". If your gonna do it do it right.

katkt is offline   Reply With Quote
Old 09-23-2006, 08:53 PM   #4
Senior MemberCaptains Club Member
PLEDGERPLEDGERPLEDGERPLEDGER
 
Snapper Head's Avatar
 
Join Date: Mar 2002
Location: Republic of West Florida - the ORIGINAL lone star state
Posts: 17,608
Default RE: adding dolphin to an outboard

Quote:
katkt - 9/23/2006 6:19 PM

Go down the main page here on THT and in the vendor forums, look for "permatrims". If your gonna do it do it right.

Hey Gordon,

What's that little stainless ring on the edge of the photo???

A towpoint of sorts?

A mini steering wheel so you can drive the boat and barefoot ski at the same time


Big Al
inquisitor
Snapper Head is offline   Reply With Quote
Old 09-23-2006, 08:59 PM   #5
Senior MemberCaptains Club Member
 
Join Date: Oct 2003
Posts: 53,969
Default Re: adding dolphin to an outboard

Ski tow ring.

http://www.bartswatersports.com/catalog.asp?P=6268
A Few Dollars is offline   Reply With Quote
Old 09-23-2006, 09:01 PM   #6
Senior MemberCaptains Club MemberPLEDGER
 
Join Date: May 2004
Location: Pensacola
Posts: 4,869
Default RE: adding dolphin to an outboard

It's a ring to tie off a ski rope or tube to. Its mounted to the step between the motors. It was on there when we purchased the boat.


katkt is offline   Reply With Quote
Old 09-23-2006, 09:22 PM   #7
Senior MemberCaptains Club Member
 
Join Date: Sep 2002
Location: On the wild side !!
Posts: 5,645
Default RE: adding dolphin to an outboard

I installed Permatrims(from SIM in the vendors forum) on my GB 2640 w/150HPDI's.

They are well made and work well !!
BW23 is offline   Reply With Quote
Old 09-23-2006, 11:52 PM   #8
Senior Member
 
Join Date: Mar 2005
Location: seattle,wa
Posts: 246
Default Re: adding dolphin to an outboard

An over simplified rule of thumb, if your boat is under about 20 feet, they work great, over about 20, you're better off going with trim tabs. I have an 18' Trophy with a 115 4 stroke, I added a doelfin and it makes a noticable difference, espically since a doelfin only costs about 40 bucks....
seaeagle2 is offline   Reply With Quote
Old 09-24-2006, 12:11 AM   #9
Senior MemberCaptains Club Member
 
Join Date: Mar 2003
Location: San Francisco Bay Area
Posts: 8,782
Default Re: adding dolphin to an outboard

Quote:
seaeagle2 - 9/23/2006 10:52 PM

An over simplified rule of thumb, if your boat is under about 20 feet, they work great, over about 20, you're better off going with trim tabs.








I agree 100%.

Plus, if the boat is over 20', you should be spending the money to get real tabs anyway. You won't regret it.

One other problem with the Doel-Fin is that they have been known to break off the cavitation plate of the O/B's and I/O's. While up on plane and speeding along, you decide to change the angle and the pressure on that fin is incredible. That same pressure can (and has) broke off the cavitation plates.

I've probably seen four or five of those so far. Each one was a boat over 20' and happened while going fast.

Of course, Doel-Fin blamed the installer, rather than just the use of their product. They did not participate in any of the repairs on the ones that I dealt with. They refused to recognize that their product had anything to do with the damage.

If you insist on having one put on, I'd recommend that you PAY a reputable shop to do it. At least that way, IF you do have an issue, you can take it back to them for assistance.

Replacing cavitation plates can be expensive.

I would imagine that the same warning holds true for the Doel-Fin knockoff, the Stingray.

Good luck!
ABoater is offline   Reply With Quote
Old 09-24-2006, 07:17 AM   #10
Senior MemberCaptains Club Member
PLEDGERPLEDGERPLEDGERPLEDGER
 
Snapper Head's Avatar
 
Join Date: Mar 2002
Location: Republic of West Florida - the ORIGINAL lone star state
Posts: 17,608
Default RE: adding dolphin to an outboard

Gordon,

Nice lookin' rig

Big Al
Snapper Head is offline   Reply With Quote
Old 09-24-2006, 07:59 AM   #11
Senior MemberCaptains Club Member
 
Join Date: Nov 2001
Location: Solomons, MD, USA
Posts: 989
Default Re: adding dolphin to an outboard

Because of the possiblility of breaking the anti-cavitation plate, I was told to get the kind that mount to the bottom of the plate and use a large portion of the surface of the plate for support. Less likely to cause stress. Here are pics of the ones I added to a pair of Yami F-115s on a 25' Parker.

I already had tabs on the boat and was toying with the idea of increasing the size of the tabs. I went with the Cobra plates instead because they were much less expensive ($60 a pop at the time). Because of the weight of the two 4-strokes, the boat was a bit transom heavy, and I was always running the motors trimmed all the way into the transom. After the plates were added, the motors are now more neutrally trimmed (plates parallel to the bottom of the hull) and the undersized tabs are much more sensitive. If I had a single motor, the OEM tabs would probably have been sufficient. But with the extra weight on the transom, I could never get the bow down to smooth the ride on a rough day.

http://classicparker.com/phpBB2/view...light=doelfins
Porkchunker is offline   Reply With Quote
Old 09-24-2006, 08:06 AM   #12
Senior MemberCaptains Club Member
 
Join Date: Nov 2001
Location: Solomons, MD, USA
Posts: 989
Default Re: adding dolphin to an outboard

For some reason the pics aren't displaying. Guess I'll have to ask the admin over on CP and maybe Wiley if they are blocked for some reason.
Porkchunker is offline   Reply With Quote
Old 09-24-2006, 08:46 AM   #13
Senior MemberCaptains Club Member
 
Join Date: Oct 2002
Location: 29 North Florida
Posts: 1,346
Default Re: adding dolphin to an outboard

How much they improve you boat may depend on which boat you have. I have had them on all my boats and some needed it and some did not improve that much. I can tell a story about a friend with a big 24 or 25 Bayliner cabin boat, made to look like a yachet, it had a 350 IO and needed help. He put the dolphin on the boat and it was a dramatic,did I say dramatic change, almost from a yugo to a sports car kinda change.
29 NORTH is offline   Reply With Quote
Old 09-24-2006, 08:47 AM   #14
Senior MemberCaptains Club Member
 
Join Date: Jan 2005
Location: massachusetts
Posts: 9,165
Default Re: adding dolphin to an outboard

I've used "doel fins" on a couple skiffs and a buddy 's boat,( that I used to practically live on.) a 25 privateer. they made a fairly significant difference on all. especially the smaller boats. problem I had was electrolysis between the stainless bolts and the aluminum plate.on one boat (a skiff witha 50 hp rude) one side actually ate it's way through far enough so that the fin fell off .I think they're a great Idea , and work well ,but I don't have one on my current boat for this reason.
north coast is offline   Reply With Quote
Old 09-24-2006, 10:57 AM   #15
Senior MemberCaptains Club MemberPLEDGER
 
Join Date: May 2004
Location: Pensacola
Posts: 4,869
Default RE: adding dolphin to an outboard

Quote:
Snapper Head - 9/24/2006 6:17 AM

Gordon,

Nice lookin' rig

Big Al
Thanks its my wifes. She lets me drive it though.
katkt is offline   Reply With Quote
Old 09-24-2006, 02:05 PM   #16
Senior MemberCaptains Club Member
 
Join Date: Jun 2002
Location: Nor\'East - MA
Posts: 2,385
Default Re: adding dolphin to an outboard

Quote:
Porkchunker - 9/24/2006 6:06 AM
For some reason the pics aren't displaying ...
[red]Pictures posted for Porkchunker ...[/red]





Reel-Rascals is offline   Reply With Quote
Old 09-24-2006, 09:41 PM   #17
Senior MemberCaptains Club Member
 
Join Date: Nov 2001
Location: Solomons, MD, USA
Posts: 989
Default Re: adding dolphin to an outboard

Dale,

Thanks for the assist. Gotta learn how to do the image thing.

Dave

aka

Porkchunker
Porkchunker is offline   Reply With Quote
Old 01-17-2015, 06:25 PM   #18
Junior Member
 
Join Date: Jan 2015
Posts: 8
Default Doelfin WOW

I bought a 12 f whaler with a 25 Mercury 4 stroke outboard as my intro into the boating world. Zipping around on the bay side of Key Largo worked fine with the motor trimmed in one pin to the transom. I thought it was normal for the boat to begrudgingly go on plane. Also, the front end seemed low once I got on plane. Went out in some rougher (1-2) seas and could NOT get on plane. I thought I sheared a hub. Surprisingly, folks I asked at the dock acted as if they had never heard of such a thing as prop slippage/ventilation. Terms I learned here. Next day off to West Marine. One size fits all didn't quite work. I trimmed the fins to fit closer around the bottom unit and redid the mount holes and it looked great. Took the boat out in small craft caution weather today and it was a different boat. Also, moved the trim pin back to prop horizontal. Boat jumped on plane. Stayed on plane at slower speeds. Handled better in chop and top speed. On flat went from 24 to 28. I can't say I have ever seen such a small $ investment make such a large change on a mechanical unit. I am a mechanical engineer by trade. I have heard about steering difficulties but whatever small steering inefficiencies I may or may not have noticed?? Are an easy trade off for me. Love the website. Will look for answers to my next boating challenge, probably marine vhf comms. Thanx
Lildevil is offline   Reply With Quote
Old 01-17-2015, 06:30 PM   #19
Senior Member
 
Join Date: May 2011
Posts: 1,583
Default

ive had many of those fins on my lower units thruout the years,the 1 thing ive always lost has been top end speed with them,any where from 1 to 4mph and 1 time a rope got wrapped around the prop.it was a mission to get all the rope out with the fin on...all in all i say its not worth the $$,time and drilling..
miamiboater2000 is offline   Reply With Quote
Old 01-17-2015, 06:43 PM   #20
Senior Member
 
Join Date: Aug 2012
Posts: 4,529
Default

Quote:
Originally Posted by seaeagle2 View Post
An over simplified rule of thumb, if your boat is under about 20 feet, they work great, over about 20, you're better off going with trim tabs. I have an 18' Trophy with a 115 4 stroke, I added a doelfin and it makes a noticable difference, espically since a doelfin only costs about 40 bucks....
My previous boat was 17' and I had proper hydraulic Bennetts - as the guy who sold them to me said, "When you think about it, the smaller the boat the more you need them." What he was referring to of course is that the size of waves and the weight of crew and cargo are greater relative to the boat, the smaller you go.

As for doelfins, some people swear by them, some people swear at them - I've know a couple of people who fitted them and pulled them straight off again as they've casued the stern of the boat to 'hop' when in a tight turn.

It seems to be they are of greatest benefit on boats with marginal holeshot performance.

But if you just generally need a bit more lift at the stern, I would consider changing the prop to one with more stern lift.

One last thing, if your engine is still in warranty, check with the dealer before fitting them - I know someone who used to work for a Mercury dealer and he reckoned fitting doelfins invalidated the warranty.
Clinker is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

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 On
Refbacks are Off

Forum Jump


All times are GMT -7. The time now is 01:27 AM.


©2009 TheHullTruth.com

Powered by vBulletin® Version 3.9.3.0
Copyright ©2000 - 2016, Jelsoft Enterprises Ltd.