Hydrofoil / Weight

[T4bus]

Zodiac 340 Act-v with 15hp

Planes and handles lovely with me, 3 growing kids & loads of kit including anchor, 2 seats, spares, tools etc. It wont get up if I remove every bit of kit & but add the Mrs, so I figure I'm asking a lot out of this outfit to get 2 adults and 3 kids up on the plane but also considder that it must be pretty close with no kit on board.
Would hydrofoils help get more weight up on the plane, I know they help get up faster & plane at slower speeds, I also know they will help if there is more weight at the back, but will they assist in getting a heavier load to plane?
I've bought a used set of LZ hydrofoils from local boat shop & was going to fit them but I'm not keen on drilling into the cavitation plate if they dont help.

I suspect it's a case of suck it and see but thought I'd enquire in case anybody had similar scenario?

Thanks

Carl

[Festinghouse]

dont be afraid of drilling - you can always fill the holes and touch up the paint. youve already got them so give them a try!

[SIBRider]

Doubt it will help. The fact that you are unable to plane with increased load tells you are not going fast enough to generate adequate lifting force because you don't have sufficient power. If you can't get it on plane by shifting load around most likely hydrofoil wont help. Also hydrofoils create additional drag and slow down more. It's possible you have some borderline case of course but only trail and error will tell then.

On the other hand seems like 15 hp should be able to do what you want. Having Tachometer (cheap induction tach is very handy investment) will help to determine if you motor performs fully. It's quite possible you are over-propped for heavy load. If you simply unable to reach rated WOT RPM switching to lower pitch propeller shall help a lot. Right now it's like trying to drive your car up the hill at 20 mph. Engine struggles because RPM are too low. Shift to lower gear you'll get going.

[dave3235]

Originally Posted by Festinghouse

dont be afraid of drilling - you can always fill the holes and touch up the paint. youve already got them so give them a try!

I had a honwave with a 15 mariner.2 12 stone chaps and myself at 19 stone,would plane nicely when the weight was spread out spread your load about not at the back some up front is good

[headdamage]

My old MkI Zodiac with 2 stroke 15hp benefited greatly in getting a load onto plane with the addition of Doul Fins.

[Peter_C]

Prop can make all the difference in the world. First you need a Tiny Tach or the like to know what RPM you are currently running.

[T4bus]

Originally Posted by dave3235

I had a honwave with a 15 mariner.2 12 stone chaps and myself at 19 stone,would plane nicely when the weight was spread out spread your load about not at the back some up front is good

So your combined weight is 43 stone, I'd guess that the combined weight of myself and 3 sons & kit is about 46 stone & the boat planes easily, so I think it's already doing OK & probably all that would be expected of it to be fair.
Im trying to get it up with the above plus the Mrs on board & the more I look at it the more unlikely I think it will happpen.

Right now all I can think is the words of Roy Scheider

[SIBRider]

Appropriate lower pitch prop will help splendidly.