# hydrofoil??



## ezbite (May 25, 2006)

i took my new boat out to the lake today (polarkraft 1470), first trip with the new motor. im still in the break in period for the outboard (Honda BF20). i had the battery and fuel tank in the rear of the boat, which i now know was a mistake (moving it forward to mid ships). i did realize i was ass heavy from the get go and a water trial proved it. i was unable to get on plane unless i leaned forward over the middle seat. there were a few white caps on the lake, it was windy and there were some big gust but when i got to open throttle i was porpising like crazy, almost to the point of being out of control. i remember an old 15' sylvan with a 25 merc i had that had a hydrofoil on it (whale tail). that boat would get on plane pretty fast. ive been reading online about them. does anyone use a hydrofoil? do they work? what are the advantages? will it stop the porpising? im not really crazy about drilling holes into a new motor.


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## Bluntman55 (Apr 23, 2016)

make sure your motor is at neutral trim , I don't remember if Hondas have an adjustable trim pin or if they are hydraulic, normally porpoising is a sign of improper trim adjustment


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## ezbite (May 25, 2006)

It's power trim and I tried every position. I knew I was ass heavy but went out anyhow just to see. Just took out the 29 battery and put a smaller 24 in and moved it forward. That should help a lot.


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## Popspastime (Apr 1, 2014)

Just for the record, I looked at one today.. On the Honda 20 there are 3 spots for the pin, did you look to see if its in the closest to the transom? The Duo-fin does a good job but slows the craft down.


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## bountyhunter (Apr 28, 2004)

# 1 they look bad #2 they tell everybody somethings wrong. #3 I,d not drill holes in your motor, keep playing you,ll get it.


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## ezbite (May 25, 2006)

Popspastime said:


> Just for the record, I looked at one today.. On the Honda 20 there are 3 spots for the pin, did you look to see if its in the closest to the transom? The Duo-fin does a good job but slows the craft down.


Yes I checked


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## ezbite (May 25, 2006)

Pretty sure it's a weight distribution issue


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## ezbite (May 25, 2006)

bountyhunter said:


> # 1 they look bad #2 they tell everybody somethings wrong. #3 I,d not drill holes in your motor, keep playing you,ll get it.


What do you mean? You don't like hydrofoils? Why? I respect your opinion and am just trying to learn. This little tin boat is new to me. Give me a 20' fiberglass and I'll get 50 out of it.


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## Eye Dr (Mar 23, 2010)

I put a Stingray hydrofoil on my old boat and it worked great. The boat was heavy and underpowered. It definitely helped get on plane faster and gained a couple mph.


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## KaGee (Sep 8, 2006)

If you haven't already, check these out...

http://www.nauticusinc.com/nauticus_resources.html


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## UFM82 (Apr 6, 2004)

Bounty, I so agree. I hate the looks of those things. And I don't like drilling holes in anything that's not supposed to have holes to start with.
That being said, weight distribution is critical in small boats like this with minimal horsepower. Once on plane, the "wedge" of water hitting the hull wants to move further back as you move forward. The bow comes up and the boat rises in the water until there isn't enough power to keep it there. Then it "falls" off the wedge. This happens quickly and that's the porpoising you are experiencing. So you have two options- move the weight so you balance out at speed or you increase your ability to hold the boat up, I.E. get more power. Since you aren't going to buy another engine you need to move weight. Take your time and get it right- the boat will be much nicer to drive and it won't fight you. Hydrofoils push the bow down and can help porpoising but they add a lot of drag when you aren't on plane and can do really funky things to a small boat if you are on plane and want to make a hard turn. 
Fix the weight issue, you'll be much happier.


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## sherman51 (Apr 12, 2011)

if its hard to get on plane you might be over propped for your motor on that boat. I would think about dropping 2 degrees and go to a rev 4 prop. this will greatly increase your lift getting you out of the hole much better and the extra lift and the 4 blades should help your high speed handling. you can add a hydrofoil at any time but for me it would be my last resort.

I have a 21' glass boat with minn kota trim tabs/ trolling motors on the rear of the boat. I have 4 batteries in the back. and with full tank and coolers and fishing gear with a 19p 3 blade prop it took forever to get on plane and run down the lake with the nose up and would beat us to death. I went to a 17p 5 blade and now it jumps on plane and has much more stern lift and keeps the bow down for a much better ride. I know this is apples to oranges between our boats. but just changing props can change the attitude of your boat.
sherman


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## bountyhunter (Apr 28, 2004)

sherm ,I like oranges. he,ll get fixed , hope he don,t drill any holes.


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## ezbite (May 25, 2006)

KaGee said:


> If you haven't already, check these out...
> 
> http://www.nauticusinc.com/nauticus_resources.html


 
ive got smart tab on my trophy, they do work well. but they really effect your steering when backing up and to install them id have to drill holes in the polar kraft transom, thats even a bigger no no to me than drilling on the cavitation plate of the motor.


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## saugmon (Jun 14, 2006)

I'm on my 3rd boat. 1st was an old bomber fish-n-ski with 90 hp johnson. Same symptoms you described ezbite. A johny ray stingray fixed it.. 2nd was a sportscraft 220 fisherman and it had trim tabs so no issue with that. My latest boat is a lowe sea nymph 165fm with 50 hp johnson 2 stroke.Brand new in 2000 and still wouldn't plane out unless I put someone up front just like my old bomber.I put the cabelas version of the johny ray jr on the cavitation plate and she planes perfectly. Steers great and perfectly matches the gray lower unit.Still holding strong at 15 yrs old now.

Looks similar to this: http://www.overtons.com/modperl/pro...rofoil-Stabilizer-1-1/2-40-hp-engines&i=28985


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## beaver (Sep 28, 2010)

I've got one on my boat, and it seems to do ok. I'm no boat expert, but it sounds like maybe I should have been more worried about weight distribution instead. I always figured that was for larger boats. I have both batteries and the gas tank tucked behind the rear seat, where I sit to run the tiller. I did that to save space in the rest of the boat so people weren't tripping over stuff. Mine is a 1648 flat bottom monarch with a 15 horse evinrude. I use it to hunt with as well as fish, so it's all spray painted camouflage. The hydrofoil doesn't stand out because it's camo as well. I think I will look for a different prop though and give it a go. I have a 3 blade now, and I can't remember what pitch. I have a few different ones, but they're all 3 blade.


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## DHower08 (Nov 20, 2015)

I have a stingray jr hydrofoil for sale would sell im not using it anymore pm me for details sell it for cheap


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## MassillonBuckeye (May 3, 2010)

Congrats on the new boat! There are some hydrofoil designs where you don't have to drill. Stingray makes a few. 


http://www.bainbridgemarine.com/PDFdocuments/STEALTH-1 - StingRay Product Lineup Sheet.pdf

Shifting the weight around might be enough I don't know. You have a troller on the front? Add that and a couple batteries and you are probably good to go.


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## fastwater (Apr 1, 2014)

Like you ezbite, this deep v 16' tiller boat with a 25hp mtr. Is not only the 1st aluminum boat I've had, but is the smallest, lightest with the smallest mtr. as well. I found out really fast about weight dist. on small tin boats with minimal hp. And like others, don't like add-ons on the mtr. or transom.

The guy that had the boat before me, had an 8hp on it. He trolled only using gas mtr or rear clamp on mounted trolling mtr. and didn't worry about planing the boat. In the back, he had 6 gal.fuel tank, two 24 series batteries, clamp on trolling mtr. the gas mtr. and a 10lb. anchor. Also in the rear on the left side is a 40 gal. Livewell that when full, with all the weight in the back made this boat look like an out of control space shuttle that would surely crash to the left.
In the front he had a bow mounted foot controlled trolling mtr. That wasn't hooked up and a 10lb. anchors.

Needless to say I was starting from scratch.

Ended up putting a 27 series batt. up front with both the anchors, building cooler and tackle storage up front and will eventually install a 20gal livewell up front turning the rear, left side livewell into life jacket storage. I removed one rear battery and rear trolling mtr.

Bottom line, as others have said, 1st play with that weight for the best performance. Then the prop. and lastly, add-ons.


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## BlueMax (Dec 3, 2006)

Move the beer cooler forward. For return trip replace beer with fish.


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## I Fish (Sep 24, 2008)

One thing I haven't seen mentioned is engine height. I know for a fact if it is mounted too low, no amount of weight distribution or trim angle is going to change it. When I rebuilt my Sylvan aluminum, I moved 3 batteries to a forward compartment, took out the original 18 gallon rear mounted gas tank, and replaced it with a 28 gallon tank in the floor mounted near the middle of the boat length wise, basically, I moved a bunch of weight forward from the original configuration.

I also raised the transom about 4 inches, meaning I had to play around with the engine height to get it right again. The motor was previously mounted on a jack plate. I tried the lowest setting first, and that caused a lot of porpoising, no matter the trim angle. Moved up one hole, and still had porpoising, just not as much. I ended up putting the jack plate back on, and with 4 inches of set back, run near the top of it. My cavitation plate is actually almost 4 inches above the bottom of the boat. 

To also note, I've used hydrofoils on 2 different boats. Yes they work, but IMO, they really are just a short cut. Get the engine height, trim angle, weight, and prop right, and you don't need them.


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## EB1221 (May 24, 2012)

EZ I've had a hydrofoil on my 17' sylvan w/50hp for a long time. works as advertised. I may have been a little underpowered trying to get on plane so it helped me. black color matched the merc and looks like factory made.
EB


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## ezbite (May 25, 2006)

I've been doing a lot of research. I'm still up in the air. I have found they now make white, black and grey. Grey would match the Honda.


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## ezbite (May 25, 2006)

I Fish said:


> One thing I haven't seen mentioned is engine height. I know for a fact if it is mounted too low, no amount of weight distribution or trim angle is going to change it. When I rebuilt my Sylvan aluminum, I moved 3 batteries to a forward compartment, took out the original 18 gallon rear mounted gas tank, and replaced it with a 28 gallon tank in the floor mounted near the middle of the boat length wise, basically, I moved a bunch of weight forward from the original configuration.
> 
> I also raised the transom about 4 inches, meaning I had to play around with the engine height to get it right again. The motor was previously mounted on a jack plate. I tried the lowest setting first, and that caused a lot of porpoising, no matter the trim angle. Moved up one hole, and still had porpoising, just not as much. I ended up putting the jack plate back on, and with 4 inches of set back, run near the top of it. My cavitation plate is actually almost 4 inches above the bottom of the boat.
> 
> To also note, I've used hydrofoils on 2 different boats. Yes they work, but IMO, they really are just a short cut. Get the engine height, trim angle, weight, and prop right, and you don't need them.


When I bought the boat I asked and made sure. I was told I need a long shaft. My cavitation plate is roughly 1"-2" below the bottom of the transome


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## I Fish (Sep 24, 2008)

ezbite said:


> When I bought the boat I asked and made sure. I was told I need a long shaft. My cavitation plate is roughly 1"-2" below the bottom of the transome


Yea, that's way to low. It should be about 1" above the bottom, not below. 1" isn't the end all height, but a good place to start. You can measure the transom. If it's around 15" that's short shaft, 20" inches is long, and 25" is extra long. Often, the transom will be somewhere in between, so, I'd play around and set your engine in a lower hole, making it higher. Each hole should make it 3/4" higher.


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## UFM82 (Apr 6, 2004)

I fish is dead on. That plate should be 1" higher than the transom at least. The plate should not be underwater when you are moving. It can cause that issue if the motor is not trimmed down far enough because the plate digs in the water. Trimmed too far forward and it will push the bow down. Either is bad. You want the water that is coming out from under the transom to "push up" against the bottom of the plate.


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## saugmon (Jun 14, 2006)

I Fish said:


> One thing I haven't seen mentioned is engine height. I know for a fact if it is mounted too low, no amount of weight distribution or trim angle is going to change it.
> 
> To also note, I've used hydrofoils on 2 different boats. Yes they work, but IMO, they really are just a short cut. Get the engine height, trim angle, weight, and prop right, and you don't need them.


Sounds to me the dealers are slacking off.These are brand spanking new boats that won't plane out correctly.They're leaving the factory that way.


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