Opinions on hydrofoils?

[Fab1]

Can i have peoples opinions on them please?The good,the bad and the ugly.

  I'm looking at getting one for my tinny in the permatrim or oz hydrofoil brand.A mate swears by them on 3 different boats he's had and I've read good and not so good about them.

   My boat sits a little low in the transom with my mrs fat rump sitting on the rear bench(Hope she's not reading this) if she is I'll have to slap her around a bit🤣😂😂😂 and I'm told they do what they say like helping lift the transom,maintain plane at slower speeds etc.

Looking forward to reading opinions.

Also one size goes up to 30hp the next size starts at 30hp.I have 30hp do i get smaller or larger size?

Cheers.

Edited January 12, 2021 by Fab1

[noelm]

They can help, but quite often they are fitted to cover a bad install, some claim more speed (impossible) some chain they are dangerous (and they can be) the best one for your problem is the permatrim, not a fin/foil thing that sticks out both sides.

[zmk1962]

Hey Fab ...

I'll comment based on my experience with an aluminium foil fitted to a 225 Yammie. That's how I bought my rig. The problem the foil was supposed to fix was to get the stern up on a plane quicker. The Haines was stern heavy. It did that. The problems it created were:

1. if the motor was trimmed out a bit and the foil bit hard it gave me some inconsistent turning experiences especially riding down the face of a wave, 

2. and more importantly the foil starting to crack the ventilation plate.  The Yammie motor ventilation plate was not designed to carry the forces this thing was exerting when under way. So I took it off.

When I spoke to my mechanic his comment was the cracking was to be expected he'd seen it before, he also said a couple of other things which made sense to me: 

1. the motor mounts on the transom were also not designed to carry the weight of the hull riding on them ... they were designed to carry the weight of the motor hanging down and pivoting, not carry an upward load. 

2. if a foil was the answer to these problems  and created a better ride all around,  then all manufacturers would be producing motors with larger ventilation plates as standard .. and competing on that design basis. But the reality is having a large flat plate running through the water often causes other undesirable hydro dynamic effects in addition to the extra drag.

These experiences could all be due to the size and weight of the haines .... but that's what I experienced.

I eventually solved my stern heavy problem largely by better balancing the boat. Also using the power tilt/trim to tuck the motor in during holeshot (which pushed the stern up) and then leveling the motor out once I started to plane. Not sure if any of these approaches are suitable to your craft ...sorry can't remember  if your motor is a power tilt/trim model ? 

So by and large I'm with Noel on my opinion regarding foils ....

Cheers Zoran

 

 

Edited November 4, 2022 by zmk1962

[frankS]

Personally I don't like them at all, agree with Noel that they can be dangerous ( very dangerous ) and people use them because they see so many other people using them. At best they are a band aid solution to a minor problem with boat set up.

Yes I have had them on a motor or two over the 60 odd years that I have been using boats, but they don't stay on long and it's usually because the previous owner of the boat OR motor fitted them.

Find the reason the boat is not acting the way you want it to and correct the reason.

Frank

[kingie chaser]

2 hours ago, Fab1 said:

Can i have peoples opinions on them please?The good,the bad and the ugly.

  I'm looking at getting one for my tinny in the permatrim or oz hydrofoil brand.A mate swears by them on 3 different boats he's had and I've read good and not so good about them.

   My boat sits a little low in the transom with my mrs fat rump sitting on the rear bench(Hope she's not reading this) if she is I'll have to slap her around a bit🤣😂😂😂 and I'm told they do what they say like helping lift the transom,maintain plane at slower speeds etc.

Looking forward to reading opinions.

Also one size goes up to 30hp the next size starts at 30hp.I have 30hp do i get smaller or larger size?

Cheers.

Its funny how I asked this question just over 4 years ago & you were the 1st person to answer-

 

After reading a bit more the overall consensus was that they help with one aspect but tend to create more problems then they solve as per Zorans answer.

 

So I never fitted one but just try to load as much heavy gear towards the bow.

 

I still with all the tackle ect forward have what I would call an average holeshot with me in the back @110kg, the motor & 25kg of fuel, at the end of the day when out solo there is only so much weight I can move forward.

 

Maybe its just the idea of drilling into a perfectly good & almost new looking motor that puts me off 😬

 

But then it could still be of benifit on the smaller motor/boat combination with less stresses that a larger vessel would produce?

 

Im still on the fence myself.

[frankS]

8 minutes ago, kingie chaser said:

Its funny how I asked this question just over 4 years ago & you were the 1st person to answer-

 

After reading a bit more the overall consensus was that they help with one aspect but tend to create more problems then they solve as per Zorans answer.

 

So I never fitted one but just try to load as much heavy gear towards the bow.

 

I still with all the tackle ect forward have what I would call an average holeshot with me in the back @110kg, the motor & 25kg of fuel, at the end of the day when out solo there is only so much weight I can move forward.

 

Maybe its just the idea of drilling into a perfectly good & almost new looking motor that puts me off 😬

 

But then it could still be of benifit on the smaller motor/boat combination with less stresses that a larger vessel would produce?

 

Im still on the fence myself.

One easy solution for you would be to get an extended fuel line and put the 25 ltrs of fuel up front.

Frank

[Rey05]

had one on an old boat, made it awful in a following sea....

 

id be looking at other fixes (proper ones) before adding a bolt on cheapie to an expensive motor. 

[kingie chaser]

2 hours ago, frankS said:

One easy solution for you would be to get an extended fuel line and put the 25 ltrs of fuel up front.

Frank

Thanks Frank, thats a very good idea.

The other good idea is I could probably lose 30kg as well, but that's not going to happen any time soon🤣

[noelm]

Simply adding weight is not the ideal way to alter trim, moving weight is the go, take stuff out of the back, and put it in the front, it's very hard to alter physics.

[Fab1]

 

5 hours ago, zmk1962 said:

Hey Fab ...

I'll comment based on my experience with an aluminium foil fitted to a 225 Yammie. That's how I bought my rig. The problem the foil was supposed to fix was to get the stern up on a plane quicker. The Haines was stern heavy. It did that. The problems it created were:

1. if the motor was trimmed out a bit and the foil bit hard it gave me some inconsistent turning experiences especially riding down the face of a wave, 

2. and more importantly the foil starting to crack the ventilation plate.  The Yammie motor ventilation plate was not designed to carry the forces this thing was exerting when under way. So I took it off.

When I spoke to my mechanic his comment was the cracking was to be expected he'd seen it before, he also said a couple of other things which made sense to me: 

1. the motor mounts on the transom were also not designed to carry the weight of the hull riding on them ... they were designed to carry the weight of the motor hanging down and pivoting, not carry an upward load. 

2. if a foil was the answer to these problems  and created a better ride all around,  then all manufacturers would be producing motors with larger ventilation plates as standard .. and competing on that design basis. But the reality is having a large flat plate running through the water often causes other undesirable hydro dynamic effects in addition to the extra drag.

These experiences could all be due to the size and weight of the haines .... but that's what I experienced.

I eventually solved my stern heavy problem largely by better balancing the boat. Also using the power tilt/trim to tuck the motor in during holeshot (which pushed the stern up) and then leveling the motor out once I started to plane. Not sure if any of these approaches are suitable to your craft ...sorry can't remember  if your motor is a power tilt/trim model ? 

So by and large I'm with Noel on my opinion regarding foils ....

Cheers 

Thanks for your excellent info.Unfortunately it's a bit late as i have just fitted one.

5 hours ago, frankS said:

Personally I don't like them at all, agree with Noel that they can be dangerous ( very dangerous ) and people use them because they see so many other people using them. At best they are a band aid solution to a minor problem with boat set up.

Yes I have had them on a motor or two over the 60 odd years that I have been using boats, but they don't stay on long and it's usually because the previous owner of the boat OR motor fitted them.

Find the reason the boat is not acting the way you want it to and correct the reason.

Frank

Fair enough. THANKS.

4 hours ago, kingie chaser said:

Its funny how I asked this question just over 4 years ago & you were the 1st person to answer-

 

After reading a bit more the overall consensus was that they help with one aspect but tend to create more problems then they solve as per Zorans answer.

 

So I never fitted one but just try to load as much heavy gear towards the bow.

 

I still with all the tackle ect forward have what I would call an average holeshot with me in the back @110kg, the motor & 25kg of fuel, at the end of the day when out solo there is only so much weight I can move forward.

 

Maybe its just the idea of drilling into a perfectly good & almost new looking motor that puts me off 😬

 

But then it could still be of benifit on the smaller motor/boat combination with less stresses that a larger vessel would produce?

 

Im still on the fence myself.

I have as much forward as possible like I think i told you in your post already.I just fitted a permatrim and will let you know how it goes.

3 hours ago, frankS said:

One easy solution for you would be to get an extended fuel line and put the 25 ltrs of fuel up front.

Frank

No room for that unfortunately mate.

3 hours ago, Rey05 said:

had one on an old boat, made it awful in a following sea....

 

id be looking at other fixes (proper ones) before adding a bolt on cheapie to an expensive motor. 

I'm not worried about following seas as i only fish calm waters.I do know they can cause broaching. If i ventured offshore I'd definitely avoid them. 

1 hour ago, motiondave said:

@Fab1 , how about she sits up front? 

How rude.😂🤣😂😂 maybe I'll tie her to the anchor rode.

33 minutes ago, noelm said:

Simply adding weight is not the ideal way to alter trim, moving weight is the go, take stuff out of the back, and put it in the front, it's very hard to alter physics.

Agree 100% No more room left to shift gear/people from back to front.

Good excuse for a bigger boat.🤣😂

[Fab1]

Well I've committed myself now haven't i.Will see how she goes.Thanks for all the comments/suggestions.

[Fab1]

[dunc333]

i have a se300 on my merc 4stroke pushing a heavy  fibreglass yalta craft hull and the bigfoot gearbox and she rides better and gets up on the plane quicker but the downside for me is it farks the tranducer tried every where and im sure its the foil as will not sound over 10 knots cheers dunc333

[Fab1]

Just now, dunc333 said:

i have a se300 on my merc 4stroke pushing a heavy  fibreglass yalta craft hull and the bigfoot gearbox and she rides better and gets up on the plane quicker but the downside for me is it farks the tranducer tried every where and im sure its the foil as will not sound over 10 knots cheers dunc333

Good to hear.I just installed the permatrim.See how she goes.It may be beneficial it may not.If it's not I'll take it off.No big deal really.

[dunc333]

they were one of the first and one of the best i have heard from yammy guys cheers dunc333

[Fab1]

Just now, dunc333 said:

they were one of the first and one of the best i have heard from yammy guys cheers dunc333

Hope you get your transducer sorted mate.

[dunc333]

thanks fab 1 let us know if it alters your tranducer at all (sounder)

[noelm]

Fab, is that a long shaft motor on a short shaft transom, or is it just the angle of the photos?

[Fab1]

10 minutes ago, noelm said:

Fab, is that a long shaft motor on a short shaft transom, or is it just the angle of the photos?

Just the angle mate and the motor is tilted.

[kingie chaser]

57 minutes ago, Fab1 said:

Well I've committed myself now haven't i.Will see how she goes.Thanks for all the comments/suggestions.

Let us know what you think after putting it through the exercises.

 

I guess seeing performance differences will be quick see, any damage to the ventilation plate will take longer to see.

 

 

[Smobaby]

If outboard motors were ment to have them it would be standard. It's not the motor it's the hull and weight distribution, trim tabs will help fix the problem even small boats benefit as other people have said they can have adverse reactions. There is another device which is some sort of box type or foil on YouTube. Hope your problems are minimised and boating  more enjoyable.

[Fab1]

1 hour ago, kingie chaser said:

Let us know what you think after putting it through the exercises.

 

I guess seeing performance differences will be quick see, any damage to the ventilation plate will take longer to see.

 

 

I'll let you know how everything goes mate.The holes are 30mm in from the ends and 15mm in from the sides of the cavitation plate.There's plenty of meat on the cavitation plate left. I also countersunk both sides of the holes slightly.I highly doubt the cavitation plate will crack.

  Also foils like SE sport/stingray etc have only 4 holes/bolts from memory.This has six which is more secure/stronger than those.They flex more too being rubber/plastic material.

  It's when holes are too close to edges with not much thickness left in the metal that issues normally arise.But there's no guarantees in life really.

Edited January 12, 2021 by Fab1

[Bowler Bob]

Hi @Fab1 It's over 12 months on from the hydrofoil fitout, wondering what your thoughts are?

As a virgin boatie retired to Port Stephens, I recently purchased a new Stacer 449 Crossfire with a Yamaha 70hp. I'm not a lightweight at around the 130kg mark and even out alone it takes forever to jump out of the hole. There is not really a lot I can do regarding weight distribution as there is not a lot on the boat. The Minn Kota battery is well forward and I will put the esky and tackle box forward as well, but in truth not much weight in them anyway.

I need to take it for it's first 20hr service in a month or two and have discussed with the dealer about putting a hydrofoil on it at the same time, so interested in your thoughts...

Cheers BB

 

[Plethora]

On 1/12/2021 at 11:14 AM, Fab1 said:

Can i have peoples opinions on them please?The good,the bad and the ugly.

  I'm looking at getting one for my tinny in the permatrim or oz hydrofoil brand.A mate swears by them on 3 different boats he's had and I've read good and not so good about them.

   My boat sits a little low in the transom with my mrs fat rump sitting on the rear bench(Hope she's not reading this) if she is I'll have to slap her around a bit🤣😂😂😂 and I'm told they do what they say like helping lift the transom,maintain plane at slower speeds etc.

Looking forward to reading opinions.

Also one size goes up to 30hp the next size starts at 30hp.I have 30hp do i get smaller or larger size?

Cheers.

I have  HYDROFOIL SE SPORT 300 (Plastic) on my Etec 115 the best thing I ever did to lift the arse up out of the water and plane quicker, after been told not to as in a tight turn it would turn my boat over (RUBBISH)  

[Fab1]

10 hours ago, Bowler Bob said:

Hi @Fab1 It's over 12 months on from the hydrofoil fitout, wondering what your thoughts are?

As a virgin boatie retired to Port Stephens, I recently purchased a new Stacer 449 Crossfire with a Yamaha 70hp. I'm not a lightweight at around the 130kg mark and even out alone it takes forever to jump out of the hole. There is not really a lot I can do regarding weight distribution as there is not a lot on the boat. The Minn Kota battery is well forward and I will put the esky and tackle box forward as well, but in truth not much weight in them anyway.

I need to take it for it's first 20hr service in a month or two and have discussed with the dealer about putting a hydrofoil on it at the same time, so interested in your thoughts...

Cheers BB

 

To be honest due to Covid and family issues I’ve only been out twice I think since putting it on.My boat is smaller in length with less than half your hp at 4.2m and 30hp.

  The first thing I noticed when fitting my permatrim was how quickly my boat planed,how slowly it would maintain plane before falling off the plane and how good it steered compared to previously.All this was good previously but it is even better now.

   I do have an issue since fitting the permatrim which caused the rear of the boat to bite in and kick out kind of feeling nearly throwing you out the side of the boat.Both times when getting hit by waves on the rear port quarter.

  Saying that my engine was incorrectly installed (too low) from dealer by at least 4 inches which took me basically 10yrs to notice as before I put hydrofoil on I didn’t have that problem or any problems regarding safety.

 I’m 99% convinced my issues are caused by the motor set too low combined with having a bigger surface area on cavitation plate due to having the fin on.I have just lifted my outboard to correct height to retest if any issues  (yet to test.)

  Some people like them and swear by them and some hate them.

  I know 7 people personally that have or had a permatrim or Oz hydrofoil on various boats I’ve talked to that have had 0 issues with them.All of them said what I’ve said that their boats planes quicker and maintain plane at lower rpm’s/speed, they save fuel,handle better,etc.

  1 person on here hates them as he had the issue I’m talking about on one of his boats @zmk1962 is very knowledgeable and hopefully he chimes in with his advice.

I will let you know how I go with motor at right height.If I don’t have that dangerous issue of boat kicking out I’ll be happy if not I’ll take the permatrim off.

Hope this helps and Zoran and others chime in.