Trim tabs...worth it or not?

[Blokatos]

I've been trying to learn more about them.

So, what do you have to say about trim tabs?

Worth it?
Does their advantages outweigh their disadvantages (added drag, cost etc.)?

Does anyone have any experience using the QL's from Volvo Penta?

If they worth it, does this apply to all boat lenghts or they are best suited to specific L.O.A.?


Thanks in advance,
Nikos

 

[hlb]

It depends largely on the boat, or how it's loaded. Some boats are noticably faster with a little trim applied. My main use is to drop the bows in head seas, so the boat rides more comfortable. There also handy as a aid to steering if one engine fails.

 

[Kawasaki]

I've been trying to learn more about them.



Does anyone have any experience using the QL's from Volvo Penta?

Yep, fitted some to a Merry Fisher 805 recently.
Reaaly effective and definately worth it.

If they worth it, does this apply to all boat lenghts or they are best suited to specific L.O.A.?

hlb answered that one


Thanks in advance,
Nikos

What is your vessel?

 

[whisper]

I've been trying to learn more about them.

So, what do you have to say about trim tabs?

Worth it?
Does their advantages outweigh their disadvantages (added drag, cost etc.)?

Does anyone have any experience using the QL's from Volvo Penta?

If they worth it, does this apply to all boat lenghts or they are best suited to specific L.O.A.?


Thanks in advance,
Nikos

Like hlb I use ours to put the nose down when heading into rough seas, and up when heading with the waves. Also they help to keep the boat level in side winds.
Personally think they are very useful but their value may vary from one boat model to another.

 

[AndieMac]

Just as the guys have said above, a good useful addition to a planing hull.

Remember you can't just set and forget, sea conditions change reguarly with wind, tides and headland formations, and the tabs need to be adjusted to suit.

For example, a head wind develops at say, 15 knots on a slight sea and the chop starts to rise.....both tabs are applied to bring the bow down for a comfortable ride.
Thirty minutes later the chop and swell has risen to more than say, 2 metres and the bow is now dropping quickly into the deeper tough behind the waves, you need to back off (lift) the tabs, and reduce speed, to allow the bow to ease down, rather than forcing it down. A lot easier on boat and crew.

 

[PCUK]

They are often essential. On my semi-d she would only achieve 10.4 knots. I fitted trim tabs and speed increased to 14 knots at the same revs!

 

[Deleted User YDKXO]

They are often essential. On my semi-d she would only achieve 10.4 knots. I fitted trim tabs and speed increased to 14 knots at the same revs!

Blimey thats a big increase, about 40%. I get about 2 knots extra out of my boat but it is a planing boat so thats only about 10% increase. Was there a logic to your choice of size and type of tabs? Just wondering whether fitting a bigger tab or doubling up would get an even higher speed?

 

[Deleted User YDKXO]

I've been trying to learn more about them.

So, what do you have to say about trim tabs?

Worth it?
Does their advantages outweigh their disadvantages (added drag, cost etc.)?

Does anyone have any experience using the QL's from Volvo Penta?

If they worth it, does this apply to all boat lenghts or they are best suited to specific L.O.A.?


Thanks in advance,
Nikos

On a shaftdrive or IPS powered boat, the tabs can be used for adjusting fore/aft trim or lateral trim. On a sterndrive boat, they're generally only used for adjusting lateral trim as you adjust the sterndrive legs themselves for fore/aft trim. As has already been pointed out, it is desirable to be able to adjust fore/aft trim, down at the bow into a head sea and up at the bow in a following sea. Sometimes adjusting the trim up or down will give a little extra speed. Many boats, particularly planing boats, lean into a beam wind to a greater or lesser degree, depending on the boat. This is because you subconsciously have to steer slightly into the wind causing the boat to lean over. Trim tabs can help to level the boat in these conditions and also when you have weight unequally distributed on the boat eg more people sitting on one side than the other.
Trim tabs are not absolutely essential but they are a very useful accessory to have. The extra drag is minimal when they are in the up position. You generally find them on boats from about 20-23ft long and upwards although many smaller boats have them too

 

[nonitoo]

In my case, because I have a relatively low powered engine for the size of boat, with a full load of bodies in the cockpit, the trim tabs make 'getting on the plane' much easier.

Once on the plane I use them for trimming the boat for the sea conditions as others have said above.

Tom