Advise Wanted: Hydrofoils + Props

[blairv]

Hi All,

Looking for some advise on Hydofoils and Props. I have a 4.2 Clark with a Stroke LS 25 on the back so it is a little underpowered but will still get me to where I want to go.

I would however like to look at improving fuel consumption which is average at best - I get to Mud and back on half a 25litre tank leaving from Fishermans Island.

So my questioms are:

1. Would a Hydrofoil improve fuel cosumption at all? (Any have any practical examples?_

2. Would a new prop (the current prop is a three blader with a bit of wear and tear) such as a 4 blade prop or even a new 3 blade prop make a difference?

Thanks

Blair

[hunter armytage]

Hi Blair

I run a hydrofoil on my motor (40 hp four stroke) and i think it helps with getting the boat on the plane quicker and keeping it there at less revs as my tinny is a similar size to yours but with a lot more weight at the rear due to the motor (100kgs) with regards to the prop selection i would give the guys at solas a ring they have helped me out in the past and are very knowledgeabl and will be able to sugest the best pro to suit your needs

[blairv]

Cheers Hunter

Have you noticed a difference before and after the Hydrofoil at all? Any change in fuel consumption?

Blair

[hunter armytage]

I cant really say as I put the hydrofoil on nearly straight away after buying the new motor and I didnt really take that much notice of the fuel usage so i would only be speculating. What i can say for sure is my top end speed increased by 5kms (now 50ks with just me in the boat) so i would think that if my speed has increased it has allowed the motor to operate more efficiently and therfore I would be getting better fuel ecconomy. I have a hydrofoil Sport SE 2000 or 3000 cant remember which size. And would recomend that you dont use the the optional fitting plate that allows you to fix the foil without bolting the foil through the cavitation plate as when i did this it created a lot more drag and thus reduced the effect of fitting the foil, rather just bolt it on.

Another thing that may be of help is to check the trim settings of your motor, I ran my old 30 hp merc for nearly a yaer before i checked the settings as i just presumed the previous owner had set these up correctly, it wasnt untill i took the time and did it myself that i realised that they were not set right and the boat was quicker for it

Hope this helps

[blairv]

Good advise - I haven't checked the entire trim setup as yet

It looks ok - I get around 40kmph out of the motor at full throttle

[blockah]

G'day mate i have a 60hp mercury 4-stroke. i ran it for a few months befor i put the hydrofoil on,

Did i notice any diff in fuel? No i don't think so, i didn't do any tests or any thing but if it did make a difference it was only minor.

It did make a difference getting on the plan at lower speeds like hunter armytage said & i think this is were you might save on fuel if at all,

I find it handles a lot better as well,

but when i was asking about them there were also some people who had nothing good to say about them at all.

but at the end of the day if i was to get another motor for some reason, yes i would put one on it.

[blairv]

thanks for the reply I think it is worth a go. Any ideas on th Prop?

[blairv]

Thought I would post a follow up to this. I fitted the original old hydrofoil that came with my engine and gave it a try when I went to Harries last week.

The difference was amazing to say the least. I covered over 40 kms (Manly to Harries, then to Mud, a good putt around various marks at Mud and then home via the channel between St Helena and Green back to Manly).

I had around quarter of a tank left and noticed the boat planed faster, less cavitation and overall around a 20-25% in fuel efficiency.

Very happy with the results so far and something you should give a try if better performance is required

Cheers

Blair

[batman]

mmm I have been eyeing off a Hydrofoil for awhile now and its on my Christmas list. I came back from North Straddie yesterday with 2 cocker spaniels, 2 labradors and four adults( 1 female, 1 pregnant missus and 2 blokes) and my 90 struggled to get on the plane.

My thoughts went straight to the hydrofoil concept.

Thanks for the post!

Batty

[blairv]

mmm I have been eyeing off a Hydrofoil for awhile now and its on my Christmas list. I came back from North Straddie yesterday with 2 cocker spaniels, 2 labradors and four adults( 1 female, 1 pregnant missus and 2 blokes) and my 90 struggled to get on the plane.

My thoughts went straight to the hydrofoil concept.

Thanks for the post!

Batty

Yes I was pleasantly suprised at the difference this made - planing was much much easier

[dog pound]

I just installed one on my rig will test this weekend and let you know the before and after ..