Hydrofoils worth the bother??? - Page 3

berkorib · 24 July 2015, 13:28

My experience shows you may plane quicker but will lose a lot on top speed - about 7 mph with a 60hp, 4.5m rib in my case.

paddlers · 24 July 2015, 18:46

Many years ago I had a little hardboat about 12/13 ft with a 35hp Chrysler fitted that wouldn't get me out on skis at 12 1/2 stone ( that weight's a distant memory !). Fitted a set of fins and it made a huge difference, straight onto the plane and stayed there even at lower speeds.
I have loads of hp now and don't bother but wouldn't hesitate to fit them if I had a problem. Just make sure nobody uses them as a step as they can snap the cavitation plate clean off.

Budgie1 · 24 July 2015, 19:14

Despite all the manufacturers claims that they will improve top speed never met anyone who's fitted them claim they actually did! I lost about 1.5 knots at WOT but it's been well worth it as previously mentioned boat far better balanced ....

Last Tango · 26 July 2015, 04:23

Stick your head over the back (when it's calm) at WOT. the fins will be flying about an inch above the water having no effect what so ever, if it's rough you aint going to be at WOT and, unless you're airborne, that "hole" in the water behind the transom will stay pretty consistent (relative to the boat) regardless of what the sea around the boat is doing.

longjohn · 26 July 2015, 12:41

Quote:

Originally Posted by Last Tango

Stick your head over the back (when it's calm) at WOT. the fins will be flying about an inch above the water having no effect what so ever, if it's rough you aint going to be at WOT and, unless you're airborne, that "hole" in the water behind the transom will stay pretty consistent (relative to the boat) regardless of what the sea around the boat is doing.

Quite correct! at WOT and correctly trimmed the fins are out of the water - so no effect on top speed - either enhancement or degrading.... but when you need them getting on the plane etc they work extremely well.

berkorib · 26 July 2015, 22:13

The hydrofoils create drag.
If you want all round better performance fit the right S/S prop.

davidni · 26 July 2015, 23:46

I would have no issue upgrading the prop if it would help, but hearing people discuss this, I get the impression you can end up going through a few props before getting it spot on, unless very lucky. I really don't relish the idea of throwing money at various props. If I have missed a trick here, please do correct me as it would be worth knowing.

Then again, the boat performance seems awesome. Nothing wrong at all. Just want to get the nose down a little at lower speeds.

I don't mind loosing some top end...the ribs like a little rocket anyway. I very rarely have the end for its flat out speed!!! I've found a nice cruising speed that I back off and settle into, where the engine settles into a nice purr yet it's going fast enough to get anywhere really quickly. All done by 'feel' at the moment as haven't sorted GPS/plotter just yet.

Blue Man · 27 July 2015, 18:38

Quote:

Originally Posted by davidni

Not a bit of offense taken. I wanted honest opinions in all shapes and forms.

You are correct. The little rib does run well...like a bullet in fact. And he does need to gain some confidence. This is more for my own benefit to be honest...until he gets to that stage.

I don't think I'm overly keen to start drilling into the cavitation plate if there are drill free options.

I think its definitely going to be either Nauticus sx smart tabs or one of the NO DRILL hydrofoils. Judging by everyone's replies and further research elsewhere...it seems that those who have tried either route have been very happy so I guess its going to be toss of the coin really as both will work out similar price. I can get either at almost exact same price.

Just have to find them some better wetsuits now as their current ones just don't seem to be doing the trick!

Smart. Kids always do better when they're warm in quality wetsuits that fit properly!

Lee40 · 27 July 2015, 18:56

Fitted them on Friday and had a blast out on the forth with the ringo.
Came in handy as my mate wanted me to go slow to start off .Mmmm okay then

For at least 30 Seconds half throttle and no probs getting out, then my hang slipped forwards to full speed.... Handled great also seamed to turn better .

davidni · 29 July 2015, 23:23

Almost forgot to get back to you all with this...

In the end I opted for a set of the SX SMART TABS in the smaller size 30.

Decision was made simply as they seemed to ignite less divided opinions from people who have fitted them.

They are composite but to be honest I have plenty of faith in composite materials as I have experience with different bits and bobs that have proved to be uber tough. Time will tell.

Got them for £100.

Had the rib out for a short run and the difference is frankly...startling!

They work an absolute treat and to be honest there really isn't any noticeable difference in top end speed at all. And I wasn't going to be too concerned if there had been as the boat behaves like a little rocket anyway, even 3 up. But its a nice surprise.

Took me 1.5 hours to fit, most of which was spent hesitating before fitting as I wanted to get it spot on first time.

They definitely seem to be point and shoot which is what I hoped for.

Little fittings allowing them to be clipped up when not required are a nice touch.

Now, as you all know...all I wanted was to get the nose down a tad at low speeds. The rib felt perfect in all other areas.

the tabs have certainly sorted that...but have done something else...cant put my finger on it...everything just seems a little more 'planted' somehow?

davidni · 29 July 2015, 23:38

And by the way...........

Thanks to everyone who replied. I would never have even known where to start without your feedback!

il corvo · 30 July 2015, 09:11

it is noticeable how much of a difference they make. my little avon 3.5 rib is slightly over engined (rated at 30hp) with a 40hp on it so tends to sit stern heavy (especially on a longer run when i have 52 litres of fuel strapped down in front of the transom) but the fins lift her backside up, runs alot more steady and flat with none of the chine riding it used to have. imo worth every penny and in my case no real loss of top end worth noting. i still get a reliable 35kts over the ground against the tidal flow and a real nice steady cruise of 20-23kts while sipping fuel like a teetotal nun.

longjohn · 30 July 2015, 18:59

Quote:

Originally Posted by berkorib

The hydrofoils create drag.

I think the drag they create in air is minimal

berkorib · 03 August 2015, 12:12

Quote:

Originally Posted by longjohn

I think the drag they create in air is minimal

Try an S/S prop for get up and go!! - I had good success with Steel Development, London

longjohn · 06 August 2015, 22:59

Quote:

Originally Posted by berkorib

Try an S/S prop for get up and go!! - I had good success with Steel Development, London

I've got a SS prop and quite honestly noticed little or no difference from the stock aluminium prop!

jonp · 07 August 2015, 01:18

Quote:

Originally Posted by longjohn

I've got a SS prop and quite honestly noticed little or no difference from the stock aluminium prop!

Ive had exactly the same results from yamaha aloy and stainless, same cruise and top speed. Not saying all props are the same pitch for pitch but modern aluminium props have come a long way.

Jon

berkorib · 07 August 2015, 09:22

A change to an S/S prop from 'Steel developments' worked for me.
I wanted more punch to pull wakeboarders out and a better top speed.
I regularly swap to the old aluminium prop from the S/S and vice versa because when cruising in shallow rivers etc I don't want to damage the S/S one. Notwithstanding that, the only two times I've damaged a prop, it was the S/S one!!
When changing them the difference is noticeable - it maybe just my boat engine setup suits the S/S prop.
Going back to Hydrofoils - I tried them when I first got the boat new, because I was sometimes struggling to pull waterskiers up (took me a week to pluck up the courage to drill the holes in the new engine cavitation plate!!). They got me onto the plane quicker but didn't help the pulling. Also the top speed was only 26 mph (2 up) vs 30 mph plus with the ali prop alone. Now with the S/S prop the boat will do 35 mph 3 up with all the skiing gear.