Achilles 9' RIB with 9.8 Tohatsu, planning?

[T37Chef]

As you know, I did it again and bought another inflatable dingy, but this is my first new one, all the others have been "new to me" A couple of questions but first a little more info...

I selected a Achilles 280 RIB (9'2") and a 9.8 Tohatsu with the idea to keep it a looong time. I wanted a dingy/tender that would fit better on our davit and our boat which has a narrow stern. I am very pleased with the fit and the Garhauer davits are handling it fine. I'm using a Forespar engine lift to handle the Tohatsu beast, nice piece of hardware btw.

Typically its myself, wife, and two daughters riding together. The weight would is under 410 lbs, plus fuel, engine, other stuff...but thats only going to increase as the kids get older right. I thought the boat would plane well with the four of us but it doesn't? It will, but not as well as I thought it should? Once on plane it is awesome! (It pops right up with just me in it and I hit about 19 knots using a GPS )

Would either of these things (fin or trim tabs) help it plane better? DO they really work on a small boat/motor like this?





WEST MARINETrimtabs at WestMarineNew

STINGRAYXPI Hydrofoils at WestMarineNew

[TQA]

Yes they will help but 4 up with a 10 hp motor is always going to be marginal.

[Gene T]

A Dole Fin will help but 9' boats are tough. I have a 10'2" Avon RIB and a Caribe C9 RIB at 9'5" and the difference is amazing. The Avon planes quickly with two adults and has a lot of control while the Caribe struggles a lot in getting on plane and staying there as you reduce power. I am using a 15hp Johnson 2 stroke weighing in at about 76 lbs. The C9 also weighs about 40lbs less than the Avon. Needless to say I don't like the way the Caribe performs. I will probably get rid of it and get a 10' inflatable floor boat.

The C9 came with my new boat as well as a Honda 4 15hp that had a Dole fin installed. I sold the Honda as I didn't want to deal with the weight. The PO indicated the added fin did help. I have installed them on power ski boats before and liked what they did to help planing. The down side is at speed they will push the bow down and lift the stern so they limit max speed.

Gene

[jrd22]

You might look into whether they offer a prop with less pitch for that engine (4 stroke?). I was able to get a lower pitch prop for a Yamaha 4hp 4 stroke and that helped (engine could rev up a bit higher) get two people up on a plane in our 10' air floor Achilles. You will lose a bit of speed with just one in the dink, but it should help get up on a plane with a big load.