The C-Brats Forum Index
HomeForumsMy TopicsCalendarEvent SignupsMemberlistOur C-DorysThe Brat MapPhotos

Twin 20hp on 16ft Cruiser. Doel Fin? Permatrim? One or two?

 
Post new topic   Reply to topic    The C-Brats Forum Index -> General Technical Discussions
View previous topic :: View next topic  
Author Message
JohnnyRambles



Joined: 09 May 2020
Posts: 11
City/Region: Michigan/Florida
PostPosted: Mon Dec 02, 2024 5:45 pm    Post subject: Twin 20hp on 16ft Cruiser. Doel Fin? Permatrim? One or two? Reply with quote

I recently purchased a well cared for 2002 16ft Cruiser with newer, low hour twin 20hp Mercury outboards. I'm considering adding some type of trim tabs or fins and was wondering if anyone has done this on the 16 Cruiser? Any thoughts on how one would go about Permatrims or Doel Fins on small twin engines? Should I use two? Or possibly 1/2 of a Doel fin on each engine? Or use two and trim them down? Any thoughts would be appreciated.
Back to top
View user's profile Send private message
DayBreak



Joined: 16 Jul 2017
Posts: 1012
City/Region: Monmouth, Or.
State or Province: OR
C-Dory Year: 2018
C-Dory Model: 23 Venture
Vessel Name: DayBreak
Photos: DayBreak
PostPosted: Tue Dec 03, 2024 10:57 pm    Post subject: Reply with quote

JohnnyRambles,

Surprised that nobody has gotten back to you sooner. Permatrims on your motors would be a great addition to get a better lift on your transom upon acceleration. I hope others will chime in but this addition will be cost effective for your needs. With our boat, we still do not have a Permatrim or whales tail type devise installed including trim tabs and we are still doing well. My advice is to try out your new purchase for one full year before making any changes.

_________________
Gary F
DayBreak, 23 Venture, 2018 - present
Back to top
View user's profile Send private message Send e-mail
thataway



Joined: 02 Nov 2003
Posts: 21354
City/Region: Pensacola
State or Province: FL
C-Dory Year: 2007
C-Dory Model: 25 Cruiser
Vessel Name: thataway
Photos: Thataway
PostPosted: Wed Dec 04, 2024 6:12 am    Post subject: Reply with quote

I have not owned a 16, but all of the C Dory seem to benefit with Permatrims. The Doel fins are not as effective (I have had one boat with the Doel Fin, which came that way. The idea is to get the bow down as much as possible for going into heavy chop--and bow up when going down wave or quartering waves aft.

With the two motors and Permatrims, you should not need trim tabs, but the 22 and 25's do better with trim tabs and Permatrims--and I am including single engine boats; not twins.

If you run on one engine at displacement speeds, with the other engine trimmed up you should get really good "fuel mileage".

It is possible that the top speed may suffer as much as a knot with the addition of the foils. But none of the C Dory (except maybe the Tom Cats) are about speed.

_________________
Bob Austin
Thataway
Thataway (Ex Seaweed) 2007 25 C Dory May 2018 to Oct. 2021
Thisaway 2006 22' CDory November 2011 to May 2018
Caracal 18 140 Suzuki 2007 to present
Thataway TomCat 255 150 Suzukis June 2006 thru August 2011
C Pelican; 1992, 22 Cruiser, 2002 thru 2006
Frequent Sea; 2003 C D 25, 2007 thru 2009
KA6PKB
Home port: Pensacola FL
Back to top
View user's profile Send private message Send e-mail
Foggy



Joined: 01 Aug 2013
Posts: 1579
City/Region: Traverse City; Northern Lake Michigan
State or Province: MI
C-Dory Year: 2014
C-Dory Model: 26 Venture
Vessel Name: Boatless in Boating Paradise
Photos: W B Nod
PostPosted: Wed Dec 04, 2024 6:39 am    Post subject: Reply with quote

My boating experience started with a 16' wooden hull Peterborough (CA) outboard
powered by a 10 HP Johnson. I learned how to waterski behind it. Over the years,
I got "2' itis" resulting in, with many other water lovers, multiple larger boats with
single engines (mostly, but not all sailbotes [cats]) and twin engines.

The single/twin engine topic has been lashed, whipped and intimidated to death -
but I will add one more component to it I have not come across: Primary propulsion
twin engines are redundant on small boats like a 16'er.

Keeping w/in the Mfg specs on HP, I feel twin engines on power boats over 20' are
more fun, better looking, definitely heavier and more expensive - all satisfying
'want' not 'need' (which kinda says 'that is' recreational boating).

Aye.
Grandpa used to say, "You become your choices. Choose wisely".

_________________
Keep an open mind just enough to not let your brain fall out.
Back to top
View user's profile Send private message Send e-mail
Joefairbanks



Joined: 02 Aug 2024
Posts: 44
City/Region: Sequim
State or Province: WA
C-Dory Year: 2006
C-Dory Model: 23 Venture
Vessel Name: Sjøhest
Photos: C-Darling
PostPosted: Wed Dec 04, 2024 6:14 pm    Post subject: Reply with quote

I have a 1991 16' Angler that I purchased earlier this year. I bought it with a 50hp Honda without trim tabs or fin of any kind. After reading many, many articles on here I bought a Permatrim for my boat. It has been by far the best addition on any boat that I have owned! Before adding the Permatrim, I had very little control of the bow of my boat. Sure, I could raise it and lower it a small amount by trimming the motor. Now, I can watch my bow raise or feel it getting stuffed by trimming my motor.
One thing that I noticed while installing my Permatrim- my antiventilation (cavitation) plate on my outboard was almost 2 inches lower than the bottom of my hull. I ran it once with the Permatrim with the motor at that height, then raised it up one hole on the transom. I am extremely happy with the results. I may have lost 1 mph in top speed, but I never run it WOT if I can help it any way. Having better control of my bow more than made up for the slight speed loss.
They don't add much width to the lower unit, so I would think it should fit fine running them on twins.

_________________
-Ken

2006 CC23 Sjøhest
1991 CD16 Angler C-Darling Sold 2025
Back to top
View user's profile Send private message Send e-mail
Display posts from previous:   
Post new topic   Reply to topic    The C-Brats Forum Index -> General Technical Discussions All times are GMT - 5 Hours
Page 1 of 1

 
     Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You cannot download files in this forum



Page generation time: 0.0414s (PHP: 42% - SQL: 58%) - SQL queries: 22 - GZIP disabled - Debug on