Will a Hydrofoil help my setup?

[simplystressed]

Hi all - I have a 14ft aluminum with a 15hp on it. It's a light aluminum but I have a floor/ front casting deck(75lbs), bow mount troller (45lbs), and two batteries(85lbs).

Running with me and the 2 batteries & gas tank at the back, i can get it to plane just fine. With two people though it doesn't want to plane out.

With 2 batteries up front (haven't tried it with just me) but it seems to skirt water over the boat and we end up getting wet. On the highest trim setting its not so bad but its not planing.

Would I be best to leave the batteries at the back and get a hydrofoil to help planing with two people? Or is this too much weight at the back of the boat? Let me know what you guys think.

 

[junior1113]

Re: Will a Hydrofoil help my setup?

is this boat flat at the back? is motor up high enough on transom? where is cavitation plate in relation to bottom of boat? fins would help but not sure if it would help enough. how is the prop what size is it?

 

[simplystressed]

Re: Will a Hydrofoil help my setup?

is this boat flat at the back? is motor up high enough on transom? where is cavitation plate in relation to bottom of boat? fins would help but not sure if it would help enough. how is the prop what size is it?

Hey thanks for the reply. I'll post a picture of the setup tonight.

 

[simplystressed]

Re: Will a Hydrofoil help my setup?

Here's a pic if that helps.

 

[NSBCraig]

Re: Will a Hydrofoil help my setup?

Run a straight edge off the bottom of the boat and measure where the anti ventilation plate is.

It looks way off in that shot, but it's hard tp tell with camera angles etc.

 

[simplystressed]

Re: Will a Hydrofoil help my setup?

Run a straight edge off the bottom of the boat and measure where the anti ventilation plate is.

It looks way off in that shot, but it's hard tp tell with camera angles etc.

Hi - the bottom plate is 1 1/2 inches below the bottom of the boat. Does that help?

 

[mickjetblue]

Re: Will a Hydrofoil help my setup?

Rule of thumb for the plate is that it should be even with the bottom of the boat.
So, I'd shim up the motor by 1.5", and then see how it performs. Should be better.
However you shim it up, the shim must be attached solidly to the transom.

Good luck!

 

[simplystressed]

Re: Will a Hydrofoil help my setup?

Rule of thumb for the plate is that it should be even with the bottom of the boat.
So, I'd shim up the motor by 1.5", and then see how it performs. Should be better.
However you shim it up, the shim must be attached solidly to the transom.

Good luck!

What would I do to secure the shim to the transom?

 

[junior1113]

Re: Will a Hydrofoil help my setup?

get your self a preasure treated 2x2 (1 1/2x1 1/2)bolt to top of transom sealing it of course and id find an alluminum c plate to to go over the transom. the way it is now you have to much drag this will help. dont know how much.

 

[simplystressed]

Re: Will a Hydrofoil help my setup?

Is there any way I can test this temporarily before drilling holes in the Transom? So a hydrofoil probably won't help my situation much?

Just wondering if I should move the batteries (85lbs total) to the back of the boat again and go from there. It doesn't spray over the sides when i do that but when they're at the front it might be a bit too much weight up there - considering the bowmount motor and casting deck already up there?

 

[junior1113]

Re: Will a Hydrofoil help my setup?

first order of bussiness get the motor up for good. why temporary it needs to go up for sure no doubt about it.

 

[simplystressed]

Re: Will a Hydrofoil help my setup?

My suzuki has the water inlets on the bottom side of the anti-ventilation plates. Should I be considering other options before moving the motor up higher?

 

[lckstckn2smknbrls]

Re: Will a Hydrofoil help my setup?

Don't use pressure treaded wood on an aluminum boat! It will cause problems.

 

[Hansolo99]

Re: Will a Hydrofoil help my setup?

Yes with a boat this small and that size motor a Hydrofoil will help for sure. They are cheap and it will help out it did on my 14' with a 50hp outboard.

 

[simplystressed]

Re: Will a Hydrofoil help my setup?

Thanks guys - I am wondering about raising it just because my water inlet is on the A/V plate - not below like most outboards. Is this an issue?

Also, with everything I have 80% of my total weight capacity filled in the boat. Could I also be dealing with an underpowered setup? Max HP is 25hp

 

[junior1113]

Re: Will a Hydrofoil help my setup?

water comes off the back of the boat on an angle. have you ever been on a tube an see how water comes of the boat and rises. right know you are plowing the plate 1.5-2" below the water. i have a merc that water inlet is under plate and i would never run it that far into the water all that extra drag is hurting you its like put you hand in the water to slow it down. fins will not help at all if they are submerged 1.5". having motor at right height is more important than prop as far as performance goes. my 72 9.8 merc would plane that boat easy and plate would be 1/2" above bottom of boat. get motor up and see. even an extruded alluminum u channel will work

 

[simplystressed]

Re: Will a Hydrofoil help my setup?

water comes off the back of the boat on an angle. have you ever been on a tube an see how water comes of the boat and rises. right know you are plowing the plate 1.5-2" below the water. i have a merc that water inlet is under plate and i would never run it that far into the water all that extra drag is hurting you its like put you hand in the water to slow it down. fins will not help at all if they are submerged 1.5". having motor at right height is more important than prop as far as performance goes. my 72 9.8 merc would plane that boat easy and plate would be 1/2" above bottom of boat. get motor up and see. even an extruded alluminum u channel will work

Junior I'll make sure I raise the transom on her and try it out. Might be able to move it up an inch to test it tonight, any further it'll need to be braced. Hard to believe it'll make that much difference....considering the weight in the boat. Anyhow stay tuned thanks for your help so far

 

[Mike(nj)]

Re: Will a Hydrofoil help my setup?

My 14' & 9.9 came about 1 1/4" higher on the transom..........lowered it and tested, guess what? It went slower. Listen to these guys and bring it up some. Get the hydrofoil too, it works.

 

[simplystressed]

Re: Will a Hydrofoil help my setup?

Update: I raised the motor up 2 inches and had it out last night. It seemed to plane a bit better, however on the trim settings that would plane it best I was getting a ton of spray off the back of the engine Water pump was working well.

Right now the anti ventilation plate is about level with the bottom of the boat. Manual says 0-1'' below the boat is optimal. Its a 15in transom and 17inch shaft motor though.

Should I be raising it up a bit more at this point maybe another inch or two?

I was surprised to see how much it was spraying.

 

[countvlad]

Re: Will a Hydrofoil help my setup?

Update: I raised the motor up 2 inches and had it out last night. It seemed to plane a bit better, however on the trim settings that would plane it best I was getting a ton of spray off the back of the engine Water pump was working well.

Right now the anti ventilation plate is about level with the bottom of the boat. Manual says 0-1'' below the boat is optimal. Its a 15in transom and 17inch shaft motor though.

Should I be raising it up a bit more at this point maybe another inch or two?

I was surprised to see how much it was spraying.

sounds like to me the water is hiting the cav plate... go up another hole ad go from there