Saturday, September 10, 2011

How can I get my zodiac style inflatable boat on a plane quicker and easier?

I have a 5 HP Tohatsu on my 9 1/2 foot Nordik(basically a zodiac) When I open up the throttle, the bow raises way up and the boat plows alot of water. I have to sit up in the bow where I can't reach the tiller handle in order to get the boat on a plane, but when it gets up I have to move to the back again or else the back end raises too high and I lose speed. Now I would rather not be moving around on a tiny boat when it is zooming at fast speeds. Can I fashion trim tabs of some sort to help the boat get on a plane? Could it be as simple as adjusting the angle of the motor?|||i had a 10foot metzler inflatable, my first boat. used to get that to plane with an 8 hp merc. however, 5hp, as said, is a a little small to plane with. inflatable boats are actually harder to get on the plane than a rib of the same size. you dont mention it its a RIB, but if it is all inflatable, what happens is, the keel flexes, increasing the drag on the hull, kind of like pulling a piece of 1/4 inch ply wood through the water, it bows up and produces a sail type effect. this is common with all inflatable keel hulls. they are designed primarily as small tenders or potter about boats, not performance craft.


only real fix for it is like what the RNLI use, and we built for our metlzer and that is a sollid deck that lays in the boat. using ply wood, cut it to fit snuggly in the bottom of the boat, and then when you inflat e it, the tubes will hold it in place. just make sure you sand the edges reallll smooth and round, so they dont cut into the sides. this will help keep the hull from flexing. its not perfect, but, it helps.


dolfins, as said, they dont really help a boat to plane out, they more help it when itsa on the plane. they produce some lift, but you stil going to have the problem of the hull flexing, and all the lift in the world isnt going to overcome that with a 5hp. when you move to the front, your bending the hull back down, allowing the ater to flow under it better and lift. as well as balancing the weight. you have the engine and yourself at the back, the stern is going to sit low, the bow is going to be weightless in comparison and just flex upwards without a fiberglass or other solid material there to keep it rigid (RIB Rigid inflatable boat)


basically im afraid, 5hp engine on a basically 10foot boat, is not going to give yo uperformance.


trim tabs etc wont help you, in fact may make it worse, as if you raise the stern using an external lifting force, and the bow is being raised by the water pushing it up, its just going to bend more in the center and may prove more dangerous.


the plywood floor or similar works well, that will help some and may get you on the plane better without moving. worth while moving the fuel tank up front and making sure it secured properly so it doesnt bounce out! that will help balance you better and mover your center of gravity forward some. you can also get tiller extensions. other than that, dunno what else to suggest.


ended up trading in the metzler for a flatacrat force 4 rib with a 35 on it. because speed was what we wanted as well as stability, and well those ribs, for the small size and weight, give that perfectly. since grown a lot bigger and now design and build my own RIBs.|||I would recommend the large trim tabs which are specifically designed for small inflatables. A google search for "detachable trim tabs inflatable boats" should come up with some listings.

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|||I put Lifters trim tabs on the boat and the boat now performs wonderfully. It gets on a plane quick, and I dont even have to lean. Overall the top speed is plenty fast enough for my fishing purposes. Thanks RIBIT.

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|||it could be as simple as adjusting the angle.........move the set pin so that the prop is further forwards and see what that does








there are also winglets sold.......name I know is Dol_Fin..that bolt on the lower unit and help plane out faster......some engine manufacturers say this voids the warranty, so check first......





and you didn't say if the boat was a RIB...if so I'm shocked it would plane with a 5!....and surprise it would plane with a wood floorboard..|||a 5 hp on a 10 foot inflatable isn't gonna get u on plane, sorry. get a bigger motor might help, cant afford one then go slow|||The previous answer probably hit the nail on the head. A 5 hp motor is a pretty small engine to be using to get a small boat up on plane. They're not really designed for that purpose. Winglets help somewhat but are better at stabilizing than planing. Also, on a small engine, they may present more parasite drag than the benefits they produce. Your best bet is to look into getting a larger engine. A 9.9 will get you up and out of the water and if you put a 15 on the back you can have a carnival ride! I have a 310 RIB and my 15 planes with 3 people on board at 21.5 knots.

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