Interceptors vs Tabs

[rbrooks]

We use the QL's on all our 32' boats they work well at speed with less efficiency loss than the tabs. However, at low speeds their performance does suffer. They will work great at 20 knots but lose effectiveness on our boat at 13-14 knots.

[tom28571]

Originally Posted by rbrooks

We use the QL's on all our 32' boats they work well at speed with less efficiency loss than the tabs. However, at low speeds their performance does suffer. They will work great at 20 knots but lose effectiveness on our boat at 13-14 knots.

Are you speaking of Fountains?

[rbrooks]

No, These QL's are on the Eastport 32 You can see the boat at www.brooksboatworks.com. However I have had much experience with the Fountains earlier in my carreer

[tom28571]

Very nice Mr Brooks,

It looks like you don't carry the topsides tumblehome well forward of the sheer break as many NC builders do. I prefer the way you do it, if I am seeing the rendering correctly.

[Willallison]

Very nice indeed!
And thanks for your thoughts on the interceptors.... it confirms my expectations.

[HJS]

I would prefer a hull that works efficient in both low and high speeds.
This boat is under construction and we hope to test it soon.
It will have an interceptor over the whole transom.
The test showes that it is possible to create a boat that works efficient in both displacement mode and in planing speed with an aft interceptor.

[Willallison]

Hmm... looks familiar.... Is it just the angle of the model, or does your chine angle down towards the bow?
HJS, it's not so much a question of efficiency - or indeed of improving efficiency - that I was referring to. In fact the boat in question achieves better than 4 nmpg regardless of speed. It's simply a matter of having the ability to trim the vessel - both laterally and longitudinally to suit the prevailing conditions.
Have you considered the effect of having an interceptor directly in the path of the propwash?

[rbrooks]

Originally Posted by tom28571

Very nice Mr Brooks,

It looks like you don't carry the topsides tumblehome well forward of the sheer break as many NC builders do. I prefer the way you do it, if I am seeing the rendering correctly.

You are correct. Some of the Carolina builders carry the tumblehome too far forward also with an extreme flair. The combination is fairly unattractive to me. I like tumblehome and flair, in reasonable moderation.
We have a new project on the drawing board. We are looking for investors to get it off the ground, if anyone is interested.

[HJS]

Willallison:

Is it just the angle of the model, or does your chine angle down towards the bow?

The chine is in this case paralell to the waterline

Have you considered the effect of having an interceptor directly in the path of the propwash?

It has been done.

HJS

[Willallison]

Interesting looking beast - do you have more pics?

[HJS]

Originally Posted by Willallison

Interesting looking beast - do you have more pics?

The beast!

[yipster]

frend of me put self made longer trim tabs on the bennets, easy done and works well