Smart Tabs

diver 1 · 10 August 2021, 12:06

Has anyone installed these on a rib

https://seamarknunn.com/acatalog/Sma...CIiQQAvD_BwE77

I'm considering adding them to my 7.4m Delta / DF250

The boat is very close to planing whilst transiting the harbour at low speed and I thought these might give the last bit of help required to achieve that.

Thanks

jeffstevens763@g · 10 August 2021, 20:41

I put tabs on a fast fisher to correct a list worked a treat didn’t look for increased ability to plane quicker but reading the info it is supposed to. I did find it a better ride not much help I know

mickter · 11 August 2021, 11:06

Quote:

Originally Posted by diver 1

Has anyone installed these on a rib

https://seamarknunn.com/acatalog/Sma...CIiQQAvD_BwE77

I'm considering adding them to my 7.4m Delta / DF250

The boat is very close to planing whilst transiting the harbour at low speed and I thought these might give the last bit of help required to achieve that.

Thanks

Not installed on my Rib,but fitted them to Explorer Elite . on the plane at lower speed and a much better ride.
would recommend if your boat is on a trailer that you fit accessory to top fixing which moves tabs so they are level with hull for launch and retrieve .

Limecc · 11 August 2021, 11:34

I wonder if they reduce Chine walking?

Not for your 250, but for small to mid sized engines a Doel Fin can be a good way to correct a poorly balanced boat by adding some stern lift. These tabs could work well on a smaller outfit instead of using a hydrofoil. The boat in the attached photo has both!

Your 250 might benefit from a four blade prop or three blade designed to give stern lift. Might just be the deciding factor if you are on the fence about changing it anyway? Is your engine set to optimal height or has that been left to original owner's judgement with no experimentation?

diver 1 · 11 August 2021, 11:55

Cheers all might give them a try. Not hard to fill a few screw holes if they dont work. I'm very pleased with the boat, might try the engine 1 hole higher, but think its about right for handling and grip. Poole harbour has always been a gripe on all the ribs I've owned, never had one yet that is happy at 10 knots. This one is very very close to sitting nicely at 10 knots so worth the investment to try something more. I'm using a Merc Mirage 3 blade Prop currently which seems ideally suited to the engine / hull. Not sure how much stern lift they give compared to others?

jonp · 12 August 2021, 02:12

Yes Ive used that brand and they did all of what they were claimed to do, however I did sell that boat so can't comment on how long they might last with the screws into plastic.

Ive also used Bennett slt (self levelling trim tabs) which are basically the same only stainless, also about the same price.

The down side of these style of tabs is reversing which will pull the stern down. Another issue is the amount of spray and direction of that spray. Depending on the hull degree they can spray water high enough to hit the engine cowling on boats with a low V. On my zodiac I ended up removing them as the water sprayed off the tabs hitting the extended tubes and back at the engine cowling and into the engine.

Not sure if you have one or looked into 4 blade props as these can help with lifting the back of the boat as well as help plane at lower speeds etc. Four blades used to sacrifice a little top end speed but there are some on the market that will actually improve that too. Look at some of the offerings such as mercury spitfire (both stainless and aluminium) quicksilver q4 (also a mercury prop ) or even the low cost turning point hustlers 4 blade.

If you use the boat offshore in kind of rough water I would stay clear of putting fins on the engine itself.

diver 1 · 12 August 2021, 08:23

Hi Jonp I looked at the Bennet ones but they didnt make a set of the 'smart tabs' rated for my size of boat / HP rating. Think they topped out at 20ft.

I think I'll do some more trials as it is and perhaps look out for a 4 blade prop. I had a 5 blade prop but on sea trials was too fine a pitch. Great for instantly launching the boat to 30 knots but also instantly hit the rev limiter too so no good.

Sutty · 12 August 2021, 10:52

The first thing I fit on a new boat is Bennet Hydraulic trim tabs. Wouldn’t be without them. Plane at slower speed if required and compensate for list or any other trim issues

Fender · 12 August 2021, 12:21

Quote:

Originally Posted by Sutty

The first thing I fit on a new boat is Bennet Hydraulic trim tabs. Wouldn’t be without them. Plane at slower speed if required and compensate for list or any other trim issues

100% right