B25 Trim Tabs

The Main Sand Box for bertram31.com

Moderators: CaptPatrick, mike ohlstein, Bruce

Post Reply
User avatar
CamB25
Senior Member
Posts: 1100
Joined: Nov 10th, '10, 08:11
Location: Wilmington, NC

B25 Trim Tabs

Post by CamB25 »

Installed 12x12 Lenco electric trim tabs on the B25. They work very well as positioned on the transom bump out. MUCH easier than trying to install outboard of this position. They are probably not as responsive in this position, but they are doing a great to keep the bow down, lower the cruise speed, and enable flat launches. Lenco was concerned that they might introduce bubbles/turbulence to the prop. I can detect no ill effects other than the wake behind the boat is not as clean as it was before the tab install. Very happy. Easy install.

https://www.amazon.com/photos/shared/F5 ... NzyRZUgc1q

Next up is the shorter setback jackplate. BTW, the jackplate came in really handy yesterday. Long story but it's tough to move with 6 inches of water under the boat. Raise the jackplate, tilt the engine and voila!, we are off the bar and running again.
1963 Bertram 25
1973 Boston Whaler 13 - sold!
1998 Scout 172 SF - beach taxi
User avatar
ktm_2000
Posts: 1000
Joined: Jul 17th, '18, 14:46
Location: Central Mass

Re: B25 Trim Tabs

Post by ktm_2000 »

Cam,

I am glad they are working well for you, to me this is a wait and see as I've run the boat for quite a few years without them

Some questions and thoughts

Where is your transducer? thru-hull?

I was also thinking of doing the same config as you on my boat. I am somewhat concerned in that I will have a rather large transducer on the starboard side and I would guess that while the tabs might not affect the ride, they would cause issues with how well the transducer works if they were to close together.

my thoughts are the stock location is kind of swiss cheese on my boat as the tabs must have been put on and changed a few times before I owned her, I had filled the holes with epoxy / thickener and covered the area in 1 layer of 1708 when I removed the tabs. I am slightly worried about putting them back in the stock locations. The mounting holes would also put the hoses in an exposed area inside my transom.

I may want to use my new found "extra" project time and fill in the area under the perimeter lip and use that area to allow tabs to be installed further outboard of the centerline if I do need them sometime in the future.
User avatar
CamB25
Senior Member
Posts: 1100
Joined: Nov 10th, '10, 08:11
Location: Wilmington, NC

Re: B25 Trim Tabs

Post by CamB25 »

I'm using a B150M thru-hull transducer - https://www.airmar.com/productdescription.html?id=72

The tabs are nice, but not 100% necessary. The ability to plane comfortably at lower speeds is a winner for me.
1963 Bertram 25
1973 Boston Whaler 13 - sold!
1998 Scout 172 SF - beach taxi
HotSpot
Posts: 131
Joined: May 9th, '18, 12:03
Location: Illinois/Wisconsin

Re: B25 Trim Tabs

Post by HotSpot »

Thanks for posting this,Cam.

What are your thoughts on the difficulty of installing outboard of that position? Would the same model (12”) ones fit in that recessed notch just outboard of the position you selected?

I had searched the board for the appropriate size and placement for a 25 with dual outdrives, with no definitive answer. Sounds like you thought this through as you usually do.

And gawd... from any angle, even the business end, that’s a pretty boat.
HotSpot - ‘61 25 Sport Convertible - Hull# 25-109
User avatar
CamB25
Senior Member
Posts: 1100
Joined: Nov 10th, '10, 08:11
Location: Wilmington, NC

Re: B25 Trim Tabs

Post by CamB25 »

The simple answer is yes, but bring a grinder with a cut off wheel. You'll need adjust the backing plate to fit. Two primary reasons I decided not to install there: 1) Swim platform interference - need 14" clear to mount the ram, 2) hard chine - I'm not sure how the water flow would change around the hard chines and didn't want to find out! Well...3 reasons. 3) that area may not perpendicular to the hull side. I didn't measure it, but I think it's an angle.

I had the boat out yesterday for joy ride. It's running well, so I'll have to find something to fix quick, or I'll get bored! Ha! My engine is out warranty now, so I'm running it like I stole it. Fun!
1963 Bertram 25
1973 Boston Whaler 13 - sold!
1998 Scout 172 SF - beach taxi
beachbum
Posts: 72
Joined: Oct 4th, '20, 08:44

Re: B25 Trim Tabs

Post by beachbum »

Very nice indeed - yeah I guess in that position the tabs will have much more influence on the bow height than positioned further out (where mine are).

You guys in the US keep your boats in such unbelievably good condition, at least that's how it looks from the photos!
User avatar
ktm_2000
Posts: 1000
Joined: Jul 17th, '18, 14:46
Location: Central Mass

Re: B25 Trim Tabs

Post by ktm_2000 »

Beachbum, I don't think you can put Cam in the group of average boaters. His boat looks like a work of art.
beachbum
Posts: 72
Joined: Oct 4th, '20, 08:44

Re: B25 Trim Tabs

Post by beachbum »

Well let's just say that my 1968 B25 looks like it was built in 1968, every picture of a 31 / 28 / 25 on this site shows really top condition boats.

That stern photo of Cam's boat looks like something that's just rolled out of a factory!

(On the plus side, I got my mini gas stove working today so I can make a cup of tea at last :-D )
HotSpot
Posts: 131
Joined: May 9th, '18, 12:03
Location: Illinois/Wisconsin

Re: B25 Trim Tabs

Post by HotSpot »

CamB25 wrote: Apr 12th, '21, 14:21 Two primary reasons I decided not to install there: 1) Swim platform interference - need 14" clear to mount the ram,
Ya, looks like the rams had just enough clearance from the platform where you put them. Thanks for the info, this is really helpful.
HotSpot - ‘61 25 Sport Convertible - Hull# 25-109
User avatar
Carl
Senior Member
Posts: 6082
Joined: Jul 5th, '06, 06:45
Location: Staten Island NY

Re: B25 Trim Tabs

Post by Carl »

beachbum wrote: Apr 12th, '21, 16:32 Well let's just say that my 1968 B25 looks like it was built in 1968, every picture of a 31 / 28 / 25 on this site shows really top condition boats.

That stern photo of Cam's boat looks like something that's just rolled out of a factory!

(On the plus side, I got my mini gas stove working today so I can make a cup of tea at last :-D )


Well take a look at mine and that will change your opinion of "all" the boats on here and make you feel quite at home.

Cams boat looks nothing like a boat rolling out of any factory I know...maybe more along the lines of a High End Custom Boat Builder.



If tight for space consider the Volvo QL Wedge Tabs

https://internal.bdoutdoors.com/2014/07 ... 1bce09.pdf
HotSpot
Posts: 131
Joined: May 9th, '18, 12:03
Location: Illinois/Wisconsin

Re: B25 Trim Tabs

Post by HotSpot »

Regarding the related switch gear... Are the ones that have the lighted trim position indicator necessary? Or somewhat useful?

Seems to be a couple hundred dollar premium over standard switches.
HotSpot - ‘61 25 Sport Convertible - Hull# 25-109
Sheer Folly
Posts: 25
Joined: Feb 23rd, '18, 08:32

Re: B25 Trim Tabs

Post by Sheer Folly »

I know I’d like to have them, if I forget to bring my tabs up all the way I can’t back into my dock slip worth a dam!
User avatar
Carl
Senior Member
Posts: 6082
Joined: Jul 5th, '06, 06:45
Location: Staten Island NY

Re: B25 Trim Tabs

Post by Carl »

HotSpot wrote: Apr 13th, '21, 19:30 Regarding the related switch gear... Are the ones that have the lighted trim position indicator necessary? Or somewhat useful?

Seems to be a couple hundred dollar premium over standard switches.


If you can't remember to bring them up when your slowing down coming off plane a light on the dash isn't gonna help you much.

For me, bringing tabs up is part of throttling down and becomes a habit.
Sheer Folly
Posts: 25
Joined: Feb 23rd, '18, 08:32

Re: B25 Trim Tabs

Post by Sheer Folly »

Carl, you’re right, but the older I get the more “forgetter” I get. I’m 74 and counting.
User avatar
CamB25
Senior Member
Posts: 1100
Joined: Nov 10th, '10, 08:11
Location: Wilmington, NC

Re: B25 Trim Tabs

Post by CamB25 »

I bought the controller with the indicator lights and the auto-retract function. I like the lights, but with enough experience with the boat and the tabs, I'm sure they are not necessary. Auto-retract is nice - 12volt sensing circuit off the key switch. Key off - tabs retract.

I have about $800 in parts for the system, including anti-fouling paint, anodes, cables, tabs, actuator switch, etc. I spent about one full working day installing everything....maybe an hour or two more. Not difficult.
1963 Bertram 25
1973 Boston Whaler 13 - sold!
1998 Scout 172 SF - beach taxi
Post Reply

Who is online

Users browsing this forum: No registered users and 91 guests