fuel monitor and Tabs

[peterbo3]

Marty,
My fuel monitor is a dipstick with notches. I believe that more is less, as in "more electronics - more potential to stuff up". Put the money that the fuel monitoring system will cost into fuel or reels, cos you will still go out regardless.
Do a cost benefit analysis on how much fuel you will save over "X" hours V the cost of the flow meters & the associated worries as to their accuracy.
If you are running a 45' charter boat with a pair of 500HP Cats then it is a different story.

[GBC]

you really sure you want a fuel monitor AND tabs - you're in for a surprise........

[Captain Seaweed]

Thanks Pete,
I think my boat uses the same amount of fuel as a 45' charter boat! I run twin 115 2 strokes and its not unusual if we go through 250-300L of fuel per trip. I figured if I could monitor them I could possibly save on fuel.

[Captain Seaweed]

you really sure you want a fuel monitor AND tabs - you're in for a surprise........

I need tabs to correct the listing propblem and fuel monitor to get better fuel economy. Where is the surprise?

[GBC]

Sorry seaweed,
just having a little chuckle at the irony of installing water brakes, and then installing a fuel flow meter to see just how much they chew - surprise!
Don't get me wrong I think they're great - just not very aquadynamic.

[Captain Seaweed]

Yeah no worries GBC! So I guess maybe the Lencos maybe more aquadynamic or are you thinking all trim tabs for that matter?

Marty

[Grand_Marlin]

The tabs (when used properly) can actually save you money in fuel, as they are making the boat run level in the water (what Marty refers to as list), and also allows the outboard to be trimmed to a neutral trim - i.e., not tucked right in to get the nose down, which is very fuel inefficient angle to run the motor at.

The Lowrance EP-60 fuel flow meters are about $150 (+any extension cables or t-pieces for the bus network) and they connect straight to his 8200.
It won't take long to save $150 in fuel.

The effect on the aquadaynamics from tabs aren't as severe as suggested.
When a boat is at speed, it takes very little influence from a trim tab to make a big difference to the trim of a boat.
If you think outside the square and look at the difference between a Volvo QL and a Lenco ... they are in effect doing the same thing.
The trailing edge of a lenco is as far (actually further) in the water than the blade of a QL to achieve the same result.
The QL trm tabs are a very clever piece of engineering.
They also have built in features such as LED position indicators and auto retract when the key is turned off.
All this for $900.
The same thing in Lenco will cost around $1400. The led position indicators and auto retract functions are extras!

Hope this helps.

Cheers,

Pete

[GBC]

No, by nature they are just a couple of rectangular feet that hydraulically increase the wetted surface of a boat thus increasing fuel usage (and levelling etc).
I assume that the bigger ones do the job easier because they can be run closer to the hull angle to get the same result - if you get my drift. The balance to this is that the bigger they are, the more violent the stuff ups can be - as others have already said.
You'll see the numbers go up and down on the fuel flow as you drive the tabs in and out.
Dunno if any brand is better or worse.

[GBC]

Pete,

agreed they might save fuel if all one is doing is correcting a list, and trimming out the motor in good conditions.

I'd like to have the conversation once he's had them on for a while though.

Tabbing a deep V hull like seaweed's down for a quick run home thru chop costs $$$, but oh what a feeling.

[Chimo]

GBC , Marty et al

As you may know I have lencos and foils on the same hull as Marty but I still run 20" Rakers.

I find that even with the tabs all the way up; which is where they run most of the time, so they are just an extension of the hull I am still able to run the motors trimmed back / up well past the neutral setting. The lencos are only ever tabbed down any distance at slow speeds especially when there are extra bodies in the boat sitting on the "U" shapped lounge that exists in the rear of my Vag.

I have some uncertailty as to whether this is the same with QLs du to the drag i beleive thy cause and this seems to be the message from PWebster in his boat test. ie he lost a kn due to fresh antifoul treatment and another kn due to the QLs being fitted. Not attractive esp if the 1 kn loss from the qls was from them in the off position.

Marty

How many hours running sees you burning 250 to 300 lt of fuel?

Do you drag lures with one or two motors running?

I have found running around the canals and in the other 6 kn zones that using one at higher revs makes heaps less smoke and uses a lot less fuel too. Old tech motors are not too frugal at idle to low revs but thats good if you have two as you can get better performance with one off at low speeds.

Still impossible to justify new motors when there are so many advantages to keeping the V 4 old tech 115s that are still some of the best motors OMC / BRP made /makes IMHO

Cheers
Chimo

[Grand_Marlin]

G'day GBC,

Agreed that anything that increases drag has to use more fuel.
It depends on what the problem is that you are trying to fix as to whether the tabs can make you more fuel efficient or not.

For tabs to work at their best (and what they were designed for), there are some other things to consider.

Are they the right size for the boat?
Where are they positioned on the boat? A lot of bigger boats have them positioned a long way in from the edge of the boat, thus reducing their effectiveness.

Is the boat properly balanced? - load distribution front / rear and side to side.

Is the weight at the transom too heavy? - oversized hp motors, replacing 2 stroke with 4 stroke, having twin motors, bait tanks, twin batteries etc.

Do you have a poorly designed pod?
Plenty of these around ... both factory and aftermarket.
They create the problem of the boat wanting to sag in the bum... trimming the motor doesn't lift it, so trim tabs are fitted to fix a design stuff up.

If the boat doesn't have a naturally good attitude and a good stance in the water, then often trim tabs are used to try and fix major problems, not minor ones like Marty has, then yes they can and will usually use more fuel.

With Marty, his concerns are list - mainly from the torque / wind up from twin - non counter rotating motors.
Also, being able to drop the nose into a chop is a great advantage.

I agree that it will be interesting to see Marty's results an I think in this case we should be pleasantly suprised.

Cheers

Pete

[Captain Seaweed]

I am happy to give my honest reviews about this product when it is installed. I have no reason to lie about it and will post fuel figures and a review when completed....and when I get home from Fraser!
Marty

[Grand_Marlin]

Still impossible to justify new motors when there are so many advantages to keeping the V 4 old tech 115s that are still some of the best motors OMC / BRP made /makes IMHO

Cheers
Chimo

Well said.

Cheers

Pete

[roddersau]

Marty

Lindsay Fry fitted Lencos (his recommendation) to my Vagabond and they go into the Vag very well. No hydraulics just wire and simple easy tap adjusment to get the boat running level in all conditions. He also suggested the indicator lights were not necessary and again he was right as you feel it quickly and easily.

Have you got foils on your motors?
I fitted them to both of mine too well before the tabs and they also helped to lift the tail which helps economy too. By doing one at a time I got a better idea of what was helping and how much.

What props did you end up with?

Cannot help with the fuel monitor as I still go by ear with the motors up as far as I can get them which with the lencos is a long way as the lenco tabs, and bennets for that matter add to boat hull length which is what you want.

I regularly check my fuel burn /hr and it seems pretty reasonable for old tech 115HP s No doubt I would use less with new Etecs but I would lose the old motors tollerance to old fuel and water and metho and they havnt done their 2000hrs yet anyway.

IMPO the others you are talking about will cost you economy and speed due to the drag they cause. Refer to Peter Webster F& B write up and the impact they had on his current boat that he has on the market at present.

Also even with no down trim on the Lencos the boat gains rear lift and the motors do not need to be trimmed in as hard for hole shot for skiiing or bar work.


Cheers
Chimo

PS Forgot to ask how high are the motors lifted on your Vag as up seems to be what they love. NB where mine are

Hello Chimo,

I was researching on trim tabs and found your post.

I have a Haines Hunter v19C with twin Evinrude 115's that have done 770 hours ( some scoring in the bores on last service inspection) they run fine but I am curious are saying your reckon on getting 2,000 hours out of your motors?

Cheers,

Roddersau in Melb.

[Chimo]

Hi Roddersau

I must confess the 2000hrs is what my marine tech / mechanic is saying.

I complain about the smoke they blow on startup and he says thats a good thing; the shouldn't wear out. He services annually ie drops legs does impellers etc etc and so far so good.

I was thinking about new Etecs a while ago but given that the Marine Tech I have been using for some ten yrs on the motors is saying what he is about the motors and they are not likely to attract much $ on the market and they are reliable (and there are two of them) and seem happy enough with the terrible quality fuel we have these days whats the odds ........ might as well see if the techs correct IMHO

Maybe you need an OMC BRP ticketed Master Tech too. I guess thats why I'll buy motors to suit the tech who'll be servicing them and reduce my worries, hopefully.

Not sure how else one can answer you "curiosity" but .... let me know......

Cheers
Chimo