Benefits of tabs?

[Haines Boy]

Has anyone used trim tabs to rectify a running condition where the cav plate is submerged and creating drag?
Trim tab manufacturers advertise 30% lift, that tabs give and say they rectify a hull that is heavy in the rear end.
Has anyone found this to be true?
They also reckon fuel efficiency and top speed also improves.

So has anyone owned a boat prior to fitting tabs and then fit a set and experienced these benefits?
Love to hear from you.
Cheers HB

[gofishin]

Mate, do a search on here & you will find enough info to give you reading matl for a long time.

By all means fit tabs, they are great, but not for the reason you want to. Yes they will help, but fix the problem first - raise the motor if it's too deep.
cheers

[bobp]

what gofish said
lift motor first to fix drag
cav plate should be just out of the water or being splashed when boat is on the plan see link below .
http://www.veradoclub.com/smf/index.php?topic=137.0
this will also give higher wot rpms and then you will have to check manual to see if you are within manufacturer recommended rpm range .

as for trim tabs they are always an advantage on mono hull boats
bob

[ozscott]

HB - rather than getting back via the PM to your question of me, the above is good advice. My 115 had the cav plate cleared before tabs when at planing speed, however the tabs reduced the planing speed, so the motor was higher for a given lower speed...but I agree with the above that you need to re-position trial first and then look at tabs. Personally I would not own a boat anymore above 5.5 m or so that didnt have tabs. I love them.

Cheers

[Haines Boy]

Thanks lads.
Have taken your advise on board and will be raising my motor first.

Any comment on fuel savings?
I guess if the minimum planing speed is lowered then the engine is under less load so some fuel savings could be had but is it noticeable?
Cheers All

[gofishin]

Thanks lads.
Have taken your advise on board and will be raising my motor first... Good move HB.


...Any comment on fuel savings?
I guess if the minimum planing speed is lowered then the engine is under less load so some fuel savings could be had but is it noticeable?
Cheers All In certain situations yes, especially when you use them to correct longitudinal trim issues at reduced planing speeds in the nasty stuff. However, they can also increase fuel consumption too.

Tabs are there to allow the hull to work to its absolute maximum potential (when used correctly). More so, it is the boat and its occupants that is/are under less 'undesirable' loading (as well as the engine). Think of them less as a fuel saver, more as an boating enjoyment 'enhancer'.

WARNING: once you've had them, you will never go back to a mono without them!;)
cheers

[Haines Boy]

Well couldn't help dropping into Bias today to check on a set of bennetts. $850 big ones. Was bummed to discover the position indicator is an extra $400

Was my lucky day however as they had a boat show package lying around which included an all in one helm switch with indicators built in. This switch unit is $570 when purchased on its own.

The whole deal was mine for the same price as just tabs $850. Totally stoked.

My only challenge now is what do I do with the boarding ladder?

Cheers HB.

[Malcolm W]

[quote=Haines Boy;959512]Has anyone used trim tabs to rectify a running condition where the cav plate is submerged and creating drag?
Trim tab manufacturers advertise 30% lift, that tabs give and say they rectify a hull that is heavy in the rear end.
Has anyone found this to be true?
They also reckon fuel efficiency and top speed also improves.

May be true that they rectify a heavy hull in the rear, but its opposite for a hull thats a little front heavy(5.6 ali 115 yam). I fittted them to rectify a listing problem and found that they just slowed the boat down( dropped 3-4 knts) and used more fuel as the front of the boat dug in more. In the end it was easier and cheaper to adjust the boats weight( scuba tanks, deckies, etc) and engine height. Also changed props. Got rid of the tabs and my next move will be to move the fuel tank a bit if its possible.

[Skusto]

[quote=Haines Boy;959512]Has anyone used trim tabs to rectify a running condition where the cav plate is submerged and creating drag?
Trim tab manufacturers advertise 30% lift, that tabs give and say they rectify a hull that is heavy in the rear end.
Has anyone found this to be true?
They also reckon fuel efficiency and top speed also improves.

May be true that they rectify a heavy hull in the rear, but its opposite for a hull thats a little front heavy(5.6 ali 115 yam). I fittted them to rectify a listing problem and found that they just slowed the boat down( dropped 3-4 knts) and used more fuel as the front of the boat dug in more. In the end it was easier and cheaper to adjust the boats weight( scuba tanks, deckies, etc) and engine height. Also changed props. Got rid of the tabs and my next move will be to move the fuel tank a bit if its possible.


hi malcolm w i have a 560 barcrusher with tabs and have found they make the nose bury alittle even when fully retracked i have found the tabs were installed to low and should be up about a cm from bottom, is yours also a barcrusher?.

[Skusto]

[quote=Haines Boy;959512]Has anyone used trim tabs to rectify a running condition where the cav plate is submerged and creating drag?
Trim tab manufacturers advertise 30% lift, that tabs give and say they rectify a hull that is heavy in the rear end.
Has anyone found this to be true?
They also reckon fuel efficiency and top speed also improves.

May be true that they rectify a heavy hull in the rear, but its opposite for a hull thats a little front heavy(5.6 ali 115 yam). I fittted them to rectify a listing problem and found that they just slowed the boat down( dropped 3-4 knts) and used more fuel as the front of the boat dug in more. In the end it was easier and cheaper to adjust the boats weight( scuba tanks, deckies, etc) and engine height. Also changed props. Got rid of the tabs and my next move will be to move the fuel tank a bit if its possible.



hi malcolm w i have tabs on 560 barcrusher and have found the nose burys a little even with tabs fully retracked. i have found tabs are installed to low and should be about one cm from bottom. Is your boat a barcrusher as well?

[Malcolm W]

[quote=Malcolm W;960707]



hi malcolm w i have tabs on 560 barcrusher and have found the nose burys a little even with tabs fully retracked. i have found tabs are installed to low and should be about one cm from bottom. Is your boat a barcrusher as well?

Hi Skusto,

The boat is an Alutech, a heavy deep v plate boat. Probably not a lot different to a bar crusher but without the ballast, it has large reverse chines to compensate for the deadrise. It a good boat running into a heavy chop or wind, but not so good in a following sea as it seems to be heavy on the front and bog down. I had the tabs 10mm above the bottom and found they did a great job of evening the boat up. But as soon as they were trimmed down you could hear the motor drop revs regardless of the motor trim. My thinking is that they are useful, but a maybe working on engine height and balancing the boat is a better option.