Foils

[Hornet]

G'DAY
I believe that you can have wedge inserts installed top part of transom mounting bolts instead of a foil .Does anyone know the pros and cons of these wedges compared to the foils .I have a hornet with a 40hp yammie REGARDS Peter.

[budgie]

G'day Peter,
I believe wedges at the transom mount point would only change the tilt/trim angle at the best, foils provide a greater surface area for lift/thrust at the business end (prop). Cheers, Budgie

[Jack_Lives_Here]

Not sure on those wedge inserts you mention. A foil will allow you get on the plane quicker and plane at lower speeds. I've got a solas foil on my hornet - wors a treat.

[Big_Kev]

You can get wedges off the shelf but you will have to look around. They will help if you have a trim problem with your boat. Ski boats in particular use them and even an extended mounting bracket.
But before you go spending the hard earned cabbage I would recomend to look at the weight distribution in the boat, just might fix the problem.And consider if the engine has enough power for the job at hand.
Personally I do not like foils, my opinion is that boat manufacturers such as Quintrex know enough about boats to build them not to require them and the evils ascociated with them are not worth the hassle.
Cheers Kev

[Jack_Lives_Here]

Unfortunately Kev I think the Hornets won't run at speed without them - too much porpoising (spelling). Had to fit it on all 3 of my hornets even after adjusting motor height etc.

[Big_Kev]

Jack I have a mate that has a Quinny 6mtr and he says that it does the same .
Is this a trait of the millenium hull?
From what all Hornet owners say (even Quinnys in general) they love their boats but this is the first I have heard of a need to fit a foil.
Learn a bit every day I guess.
Cheers Kev.

[SherKahn]

Sorry but me trying to learn. Me ask a stupid question. What is a foil?And what does it do?What is a wedge?What does that do?

[Jack_Lives_Here]

A foil attaches to the cavatation plate (the horizontal plate above the propeller) and increases the surface area, allowing the boat the plane much quicker and at lower speeds generally.

Wedges, I believe, fit between the top of the transom and the motor to adjust trim angle.

[SherKahn]

Me Understand now thanks Jack_Lives_Here

[BurdekinBob]

Reel Hard,
All planing hulled boats will porpoise if the motor is trimmed out too far. My 475 Millenium does not and never has porpoised with or without the Solas Foil which is now fitted on it. The advantages of a foil far outweigh the disadvantages, (if any).

[Big_Kev]

Bob,
Jack has stated that he has fitted a foil to his boat to counteract porpoising at speed.
You have stated that your boat does not and has never porpoised.
It is my opinion that a foil fitted to the Cav Plate has negative effects upon the leg of the outboard to act in its design as a rudder.
It is also my opinion that to much lift can be created, causing the hull to broach in a following sea, forcing the nose of the hull to follow a wave along its length. Of which is countered by triming the nose up. Therefore as you have stated will cause the hull to porpoise.
I think that if you have one and like them that is good, but I think that they can be dangerous and are a waste of good money.
Cheers Kev

[aussiebasser]

It depends on the brand of foil you buy, and what you are trying to achieve with it. If you have a hull that runs dramatically nose high, fit a Stingray. If you have a hull that rides flat, and you just want the foil to assist in the transition onto the plane, and to hold a lower planing speed, go for an SE Sport or Permatrim. I've just put a permatrim on my Hornet and I will do some comparisons with the SE Sport I took off. As far as the 400 Hornet becoming dangerous as it broaches in a big sea. What would you be doing in a big sea in a 400 Hornet?? The SE Sport will give you better performance at some slight cost to top end speed. The Stingray will give you a nose down ride with a big cost to top end speed. I'll reserve my opinion on the Permatrim until I've given it a run, and hope I haven't wasted $139.00.

[peterbo3]

Evening All,
I have a 5.3M Lightning Plate C/C powered by a 75HP Mariner spinning a 17inch alloy prop. Motor has a Stingray foil fitted. Top speed at WOT (5200 RPM) is 31 knots by GPS through "slack water." Load was two people, esky, 160L of fuel and the normal stuff that finds it's way on board. The boat will stay on the plane down to approx 10 knots from a faster speed. Up onto the plane in about 2 to 3 boat lengths.
I cannot provide a comparison for performance levels without the foil as it was fitted when I purchased the boat but I can say that I am very happy with the way the foil seems to work.
The only drawback seems to be a slight tendency to cavitate at high speed on hard turns. Fixed that problem by pulling back on the revs or turning less sharply. This was only a problem in places like Pumicestone where the channel markers are close together & the channel is narrow & winding.
I have had no problems with the way the boat handles in any sea condition or trim position. Following or quartering stern seas do not cause any hint of a broach or deviation from course.

[aussiebasser]

Well, I finally had a run with the Permatrim on the Hornet, and it is a completely different boat to drive now. With one-up, the porpoising has been completely eliminated, and at full noise, the Permatrim is clear of the water so now drag. I don't have a Tacho, but the overrev alarm spent a fair bit of time cheaping at me. The best speed I saw on the GPS was 37mph, and that is faster than it has gone with this prop.

[NQCairns]

Hey Aussiebasser, I seems as if you are impressed by the new foil that is good. I was wondering how it now has a higher top end? was the old foil still under water at wot ie mounted lower? cheers Scott.

[aussiebasser]

My guess is that the leading edge of the old foil was thicker, and created more drag than the Permatrim.

[SteveCan]

It is my opinion that a foil fitted to the Cav Plate has negative effects upon the leg of the outboard to act in its design as a rudder.
It is also my opinion that to much lift can be created, causing the hull to broach in a following sea, forcing the nose of the hull to follow a wave along its length.


I Have to agree with Kev. I had a foil fitted to my 16ft fibre runabout before I really got to know the boat properly. I had bad problems with broaching and trimming didn't make much difference. As soon as the foil was removed it perfomed Heaps better. Interestingly - the speed on flat water at 4500 revs was up from 41k to 46k - about 10% difference.

I reached the conclusion that they didn't work well on my boat ;) They must do well for other boats or they wouldn't be so popular #???

From what I have read, most of the boats that seem to benefit are flat water or inshore boats. Perhaps Foils are more suited to condtions in the creeks, lakes and rivers rather than outside?

Cheers
Steve.

[mackmauler]

I have a foil on my rig, not sure what type, it looks to be black plastic shark fins that bolt onto the cav plate ;) stopped the cavitation I was getting and holds the boat on the plane at low speed, also helps with acceleration in the bar, my boats got tubes which makes it hard to compare to standard hulls, maybe the extra stability of the boat makes up for the few bad points foils can have ???

[jaybee]

I have to agree with kev as well on the foil acting as a rudder, i purchased a 16 fto boat with one fitted on a glassed out day (the test) three on board couldnt fault it, the first run a few weeks later off mooloolaba couldnt get over 10 knots in a following sea was damn dangerous with the foil lifting the stern and digging in from side to side was broaching fairly badly, took the foil off 25 knots in a following sea no probs, boat is a little bow high but is very comfortable in a bit of slop.
cheers
joe.