trim tabs ?

pacific marlin · Post by **pacific marlin** » Sep 13th, '07, 05:53

Hi all,
After having re built the B 28 and shipping her to Antigua, I thought I needed a winter project ,so I found and bought a B31 Sedan.
Now this may not seem unusuall to you guys but to find any kind of Bertram over here in the UK is a rarity in its self let alone a basically original Sedan.
So my first question is, should I keep the trim tabs or leave them off after the strip down and re build?
Any pros or cons ?
Regards Ian

Josh Johnson · Post by **Josh Johnson** » Sep 13th, '07, 08:02

In general they're probably used mostly for pitch control and you may or may not have a problem with pitch in the 31 Sedan. I'll let the 31 guys speak on that. But on my 25 Flybridge, I've found them most useful for roll control, especially for unbalanced lateral loading, or continuous off-angle seas.

Harv · Post by **Harv** » Sep 13th, '07, 08:58

The simple rule of thumb seems to be...if you have them, keep them . If you don't, don't worry. My boat came with tabs when I got her. So did my previous boat. I use them with no complaints. In rough seas, I trim her bow down to blast through the waves. In calm seas, I trim her bow up with slight adjustments to keep her level. The most common complaint I have ever heard is they cut off lines while fishing. In over 35 years of fishing with trim tabs, I have never lost a fish because of them. Rudders and props however are a different story. I come from a simple school of thought whereas I would rather have something and not need it, than need it and not have it.

DRIFTER31 · Post by **DRIFTER31** » Sep 13th, '07, 10:12

Well said Harv.... Ian how is Howard at Curtain Bluff? I was there a few years back.My friend Mike Davis worked there for 10 or so yrs.Antigua is a very sweet part of the world.Not too big not too small and no crime. Many times i wished i could live on that island.P.S if you ever need a hand with something i have restored several boats myself and am in the auto re-finish buisness and could paint that 31 to look new again. Best regards. Troy Danos tdanos@cox.net

ZeroCavity · Post by **ZeroCavity** » Sep 13th, '07, 11:08

I have the Volvo QL Trim Tabs and liked them a lot.

http://www.great-water.com/pages/produc ... im_Sys.htm

CaptPatrick · Post by **CaptPatrick** » Sep 13th, '07, 12:05

Guys,

Gerry is right & the system is dead simple, fast/easy to install, & the price is short money compared to hydraulic or other electrical systems.

The units are electrically controlled, no cylinders, no overhang, & nothing sharp. Also, for those of you who have, or are familiar with, standard type tabs, you know what happens when you do a hard backdown with out remembering to raise the tabs first... Yep, ya' break the suckers off. This can't happen with the QLs because the force of the water isn't levering against anything.

The concept with the QLs is to drive a narrow blade straight down by a mater of fractions of an inch. This creates a "hook" at the transom edge that forces the transom up & bow down. Neat, simple, inexpensive system...

The only potential problem is that they are fairly new to the market, so don't have the time honored & tested background as do most of the standard type tabs. A problem that wouldn't slow me down from buying them.

Br,

Patrick

Harv · Post by **Harv** » Sep 13th, '07, 13:07

Patrick,

Given enough resistance, would these be able to be used to slow down trolling speeds?

CaptPatrick · Post by **CaptPatrick** » Sep 13th, '07, 13:55

Harv,

I doubt that you'd see any difference at all in trolling speed, even with them extended to the max...

However, on the other hand you might be able to figure out another gizzmeux that uses the same principal, only put on & take off manually. You'd have to experiment with the blade size, but it'd probably be in the 1'x2' size range, below the transom/hull intersection. Kind of a removable standard trim tab that would a full 90 degrees down, (perpendicular to the hull bottom).

Br,

Patrick

Capt Dick Dean · Post by **Capt Dick Dean** » Sep 13th, '07, 13:56

I have trim tabs and love 'em. Change the pitch and see the boat speed change. But if you have a fat crew, just tell to go forward or aft. Same deal!

ianupton · Post by **ianupton** » Sep 13th, '07, 16:52

Ian,

Congrats on the purchase!

Did you happen to pick this up from a marina / broker in Ontario, Canada?

If you did, I crawled around on this a few weeks ago with John Swick. You just purchased yourself a very original, freshwater its' whole life B31.

Good Luck!

Ian.

Carl · Post by **Carl** » Sep 13th, '07, 18:06

Aside from a short tower I would recommend the tabs for the Express (sedan). I will probley be putting them on next season as now with new larger tank the bow does not come down at slowwer cruising speeds like she used to.

I mention tower or tabs, maybe both, we have lots of wood and debris in water around here. In a 2' chop you can still move along at a fair pace but with bow up a bit and at the lower helm you just can't see into those troughs and that is where the debris always seems to be sitting. Tabs may bring the nose down a bit giving a better view, ride etc.

I do like the idea of those QL tabs, even though I never had a problem with tabs on my other boats. Just those seem a whole lot simpler.

I'd like to see a comparison between tabs and the QL units. Wonder if more drag with QL's. I have also heard tabs extend the boats waterline lenght which was supposed to be good.

Harv · Post by **Harv** » Sep 13th, '07, 23:35

CaptPatrick wrote:Harv,

I doubt that you'd see any difference at all in trolling speed, even with them extended to the max...

However, on the other hand you might be able to figure out another gizzmeux that uses the same principal, only put on & take off manually. You'd have to experiment with the blade size, but it'd probably be in the 1'x2' size range, below the transom/hull intersection. Kind of a removable standard trim tab that would a full 90 degrees down, (perpendicular to the hull bottom).

Br,

Patrick

Patrick,

I had a thought along those same ideas. My thought was to put 2 perpendicular panels behind each prop on the transom. Sort of the same principle of reverse thruster on a jet engine to slow it down. Enough resistance should create the right amount of drag to troll slow enough for stripers as opposed to trolling valves or bumping 1 engine in and out of gear to troll slow. Don't know if I want to put anything so visually conspicuous on the transom to take away from the good looking lines of the boat.

Charlie J · Post by **Charlie J** » Sep 14th, '07, 04:47

trim tabs the on going debate, think harv said it well if you have them then keep them. i had them on my 31 fbc and rarly use them, dont have or need them on my bahia mar.

capy · Post by **capy** » Sep 14th, '07, 08:58

The only time I value mine is going on a course perpendicular to a 15knot or higher breeze....roll control.

Harv · Post by **Harv** » Sep 14th, '07, 11:49

Here's a possible decision maker.
Charlie and I both have Bahia Mars.
Coming home from the first Atlantic City Rendezvous we
ran into some pretty tough conditions. We were talking
back and forth the whole time we were crossing from Jersey
to Long Island. Many times Charlie would key up the microphone
and all I would hear were moans of pain and agony. When I asked what happened,
he said that was his reaction to flying off, or crashing
into a wave. I on the other hand, had my tabs trimmed so the bow
was punching through the waves instead of flying up
and crashing down on the back side or face of the next wave.
I beleive I heard him cursing at me when I told him I wasn't experiencing the same degree of pounding that he was.

Charlie J · Post by **Charlie J** » Sep 14th, '07, 19:03

harv
you had alot more weight in your boat!!!!!!

Rawleigh · Post by **Rawleigh** » Sep 15th, '07, 12:53

Charlie: That's not a nice thing to say about Harv!! LOL!!

Harv · Post by **Harv** » Sep 15th, '07, 23:00

Thanks Rawliegh.
If he keeps it up, I'll take his pictures down.

Bruce · Post by **Bruce** » Sep 16th, '07, 00:00

The last 31 I did, "Time Machine" did not have tabs and with the gassers, owner never needed it.

After the diesel conversion and larger props, he is riding a little more bow high and tends to pound more.

We've ordered a set of the Q-tabs and I will be installing them when they come in. Owner did not like the idea of a tab that stuck out the transom and when he saw what Gerry had on his, he wanted some.

Two things to be careful on the install.

One, the power plug to the tab is square and the hole only needs to be big enough to fit it thru. It is very close to the top of the tab and could provide a possible weak spot if over drilled.

Two, the tab is held on to the transom by two rows of 10 #14 screws for the 31 size. Stripping a hole is not wise due to the force of trying to rip the tab body off the transom when the tab is engaged.
It also is designed to be mounted on a flat surface and being plastic it will break, crack or distort when trying to mount on a curved transom with out a wedge block behind it.

If it was me, it could go either way. I'd leave them on until I was done and saw how the boat ran.

John Jackson · Post by **John Jackson** » Sep 23rd, '07, 20:15

I have tabs on mine. I find that they soften the ride considerably in a head sea or on the quarter. But, when the head sea is enough to need the tabs down, it is like a fire hose hitting the front of the boat and water gets in from any little opening. Forget about being in the cockpit in these conditions, you might as well jump in the water and get it over with. I ran back from Atlantic City on the same day as Harv. Some water got onto my dash from the zipper hole in my enclosure and cooked my Cummins circuit board under the panel. I solved that problem, but the next time I pounded into a head sea water got in through my windshield down below and cooked the switch for my fuel gauge which I installed below by my electric panel so it wouldn't get wet (kind of ironic, huh?).

The down side to the tabs is that they aren't cheap and are one more thing for guests and kids to catch thier hooks into. In my experience, they make a softer ride but make a wet boat more like a surface torpedo if the conditions call for putting the bow down.

Plus they make it harder to keep the green stuff off the back of the boat. Getting a scrub brush between the plunger and the hull is a PITA (pain in the ass).

I don't know if I would install them again. I do admit that I play around with them a lot.

In Memory of Vicroy · Post by **In Memory of Vicroy** » Sep 23rd, '07, 20:21

In my view they are simply not needed on a B31, especially one with diesels. In a head sea just slow down to the 'rocking chair' speed and enjoy the ride. If you get a list, just holler at the fat guys to move around some.

UV

randall · Post by **randall** » Sep 24th, '07, 07:46

the summer i ran with no steering i used em to change course at speed....one up and one down turns the boat bout the same as the rudders on plane

Capt. Mike Holmes · Post by **Capt. Mike Holmes** » Sep 24th, '07, 08:09

I know a doctor who says he can steer his 46 Bert than way, in an emergency.

Harv · Post by **Harv** » Sep 24th, '07, 16:42

randall wrote:the summer i ran with no steering i used em to change course at speed....one up and one down turns the boat bout the same as the rudders on plane

Sherri-Lee, the Bertram race boat that was at the AC Rendezvous, will not turn without the trim tabs being engaged.

Brewster Minton · Post by **Brewster Minton** » Sep 25th, '07, 07:55

Keep them

nic · Post by **nic** » Sep 26th, '07, 01:47

Every deep vee planing hull I have ever driven benefits from trim tabs, from 16ft to 56ft.

They are promoted to improve fore and aft trim, to me that is marginal, pulling the bow down into chop helps with some hull shapes in some trim conditions in some sea conditions.

The main benefit is countering cross winds to keep the hull upright and the deep-vee working. Any cross wind with strength will push the bow away, causing the helmsman to counter steer into the wind to maintain a straight course, causing the boat to lean into the wind bringing the windward chine down into the chop and presenting a flat hull panel to the waves and resulting pounding.

With one tab down (and I get confused which one unless I'm driving and sometimes they cross wire them) the resulting drag towards the wind forces the helmsman to turn away from the wind to maintain a straight course which counters the effect of the wind and keeps the boat upright, with the result that pounding is minimised because the chines are higher and the vee presents itself properly to cut through the waves.

Engine torque causes boats to lean as well, our Yanmars above 3,000rpm throw us to port.

I like the sound and the look of the Volvo "tabs" though I haven't used them.

My A$0.02!

Nic

Skipper Dick · Post by **Skipper Dick** » Sep 26th, '07, 07:27

I've got tabs on my B28. I barely used them when I had a light load, but when I had a heavy weight or two milling around below, I trimmed the boat out so it rode true.

Since I put flow meters on, I've found that by trimming I can get better milage. It's not an astronomical amount, but evry bit helps even a couple of tenths of a NM per gallon.

Dick

Charlie J · Post by **Charlie J** » Sep 26th, '07, 15:44

see harv it is the weight thing

Harv · Post by **Harv** » Sep 26th, '07, 20:06

cwj wrote:see harv it is the weight thing

That's it Charlie, I'm pulling down your pictures.

bob lico · Post by **bob lico** » Sep 26th, '07, 20:43

harv your a nice guy so i will tell you like it is no politics.my former life filled with sheer stupity i was a "hired gun"this is the term given to a paid driver/thottleman/navigator on a apba race boat.if you even touch those tabs on a race boat 3 minutes after the boat was craned out of the water you would hear the trump special "your fired".the only reason for tabs on a deep vee is on the second or 3rd lap when the turnboat congestion dies down the thottleman tells the driver "cut the cable"in plain english the thottleman is going around the turn balloon "balls to wall"----full thottle 120 degree turn the navigator lifts the starboard tab and plays the port to prevent a deadly barrel rollover thats the only time a navagator touches the tabs'you trim the boat with the tranfer of fuel!!!!! at 90mph dropping a tab is like putting out a anchor!!!!you will never get another paid race day again.10' seas ----no balls no babies run right into the crest if you expect to win

Capt. Mike Holmes · Post by **Capt. Mike Holmes** » Sep 26th, '07, 21:49

Bob, I spent a day in a Scarab with Gus Anastasia at the helm when he was still with Wellcraft. Nothing like your experiences, but it was pretty exciting to me.

bob lico · Post by **bob lico** » Sep 26th, '07, 22:23

mike i don`t want to give the wrong impression,as i look back at the mishaps(rotator cuff/lower back/worst of all the neck injury)for what in the mid 70ties 300.00 a day plus expences.all winnings (we won miami open/islandmorader etc.)boat owner takes all winnings usually donates it at the awards dinner.you just can`t think just react a analogy would be a three point turn in a truck just before you hit the curb you turn the wheel the opposite way. this is what happens at 70 in 6' waves you antesipate where the boat will go and react.stuff the bow and you break some teeth,barrel roll the helmet catches water and you snap your neck.all and all the price of victory was never cheap.the ride on the 38'bertram rocky "o" was 2' waves earl leneir throttle it up to 90and we hit the inlet wot 7to 8' pretty stupid but that was the way it was he who hasitated loss.

Rocket · Post by **Rocket** » Sep 26th, '07, 23:30

Hey Bob - Have you got a fan club? What a riot. I, like Nic, need to meet you too see if you speak like you write and, I suspect, drive. I would love to hear the stories....

pacific marlin · Post by **pacific marlin** » Sep 27th, '07, 03:58

Good Morning all,
Thanks for all your input re these trim tabs.
I've decided to refit them as far as the pump and see how she runs and if necessary I can then fit the tabs on her annual lift out.
Drifter I don't personally know Howard, tho I may have met him but could ask after him if you like .
Ian(upton),I found the boat in Brighton,England ,probably one of only two or three here in the UK(I'm looking for the others ! )
So my next question is this(It's my thread so I'll hijack it if I want :) )
I've removed the roof and windows but how do you seperate the curved frames from the front screens? I can't see any fixings, just the small fillet between the two.
When I conquer my technophobia I'll post some photos.
Regards Ian.

Harv · Post by **Harv** » Sep 27th, '07, 13:29

bob lico wrote:harv your a nice guy so i will tell you like it is ....you trim the boat with the tranfer of fuel!!!!!

Gary's boat had a water intake and outlet for water ballast. He said he could take on water or discharge it to compensate for the fuel usage or trim attitude of the boat. Other than that , the tabs were used for steering. His setup was quite unique in that it had twin inboards with a single rudder in the center of the transom and the tabs were immediately adjacent to the rudder.

dougl33 · Post by **dougl33** » Sep 27th, '07, 13:48

When I had my 454's on my 33 I would use the tabs to bring the bow down at my cruising speed of 18-19 knots. In this regard they worked pretty well. Now that I've got diesels and can cruise at 22-23 knots, I only use them to balance an un-even load or to bring the bow down into a crappy head sea.

Every once and a while on a flat-ass calm day I will try bringing the bow down to see if I can pick up any speed. I usually can by .5-1.0 kts, but as soon as I have to make a turn or someone moves around, the boat tends to lean over to one side. Then I wind up messing with the tabs for a few minutes to get it back on an even keel and/or I say screw it and tab all the way up. On the faster 33's (21 knots plus), you don't really need them.

If you have 'em keep 'em.

Rawleigh · Post by **Rawleigh** » Sep 27th, '07, 15:02

I like them for trimming uneven loads, compensating for wind sometimes and lowering the bow when running from the lower station. I normally don't use them, but they are nice to have.

Harv · Post by **Harv** » Sep 27th, '07, 18:39

Like I said before, better to have them and not need/use them, then to need them and not have them.

Bruce · Post by **Bruce** » Sep 28th, '07, 05:05

too see if you speak like you write

That's affirmative.

Meeting Bob is a treat but its like being in a foreign country. If you don't understand a good part of the language, your lost.

bob lico · Post by **bob lico** » Sep 30th, '07, 11:09

by reading your post (water ballast) i realized this is not apba. sorry harv i should have realized this was not the real deal.i checked my picture gallery for a apba with tabs showing.the c- boat is doing about 106mph and the v-hull 95mph in the photo.notice the tabs.

Harv · Post by **Harv** » Oct 1st, '07, 11:24

Bob,

This is Gary's boat. The hose going over the small platform is for his water intake.

And this is the picture he carries on board. He believes they are one and the same.

bertram31.com

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