max hp on dinghy

[fsudelt]

Hey all I recently got a 8.5 dinghy but after looking at davits and storage now I'm thinking a 7.5 would be better fit for storage on platform with davits. Question is my 8.5 right now shows I can have up to a 10 hp engine, but 7.5 shows only 2.5? I had just bought a 6 hp tohatsu, any thoughts on if I could get by with the 6hp still on the 7.5 if they will allow me to exchange out to the smaller? (By the way the dinghy is a Baltik). Thanks for any thoughts.

 

[Hampton]

Hey all I recently got a 8.5 dinghy but after looking at davits and storage now I'm thinking a 7.5 would be better fit for storage on platform with davits. Question is my 8.5 right now shows I can have up to a 10 hp engine, but 7.5 shows only 2.5? I had just bought a 6 hp tohatsu, any thoughts on if I could get by with the 6hp still on the 7.5 if they will allow me to exchange out to the smaller? (By the way the dinghy is a Baltik). Thanks for any thoughts.

I'm sure those dinghy's must have significantly different construction to show such a large diff in max horsepower. I wouldn't push the smaller one that far. Don't know if you can trade, but is it really worth 1' of dinghy space?

 

[fsudelt]

I called the dealership I bought the baltik from and they said the reason for diff in HP is the pontoons are smaller. (overall lengh is 1 foot shorter, and width (beam) is 6" shorter). I just looked on the Tohatsu website and my 6hp is 55 lbs and a 2.5 hp would be 41lbs. Does 14 lbs make a big diff on a that size diff boat? The reason I say all this and my swim platform is 8ft wide (my platform is integrated with gunnel wings to end of platform- or else it wouldn't really matter about width) and my dinghy is 8'6" long, so if I could go to a 7'6" it would fit just about perfect and give me more room. Of course I didn't realize this when ordering originally. Worse case I'll just have to keep 8.5 and have a tight squeeze when stored on davit (going with Hurley either 8 or 10" system)

 

[Hampton]

I just looked on the Tohatsu website and my 6hp is 55 lbs and a 2.5 hp would be 41lbs. Does 14 lbs make a big diff on a that size diff boat?

No, but 3.5 HP makes one heck of difference when you're trying to go from point A to point B.

 

[Mr Salt]

I would follow the manufacturer's recommendation. There are aq lot of differences between the two boats not the least of which is bouyance. The smaller boat will be less bouyant and when you add the weight of the people along eith the weight of the engine you could have some real issues. Torque is another real issue. Remember it is not 3.5 additional horsepower it is 2.5X the horsepower. That is a big number

Good luck with your decision process

 

[Hampton]

In case I was misunderstood, I was not implying that he should over power the smaller dinghy but that he should consider going with the larger one capable of handling the higher power. In addition to the above factors, they can get quite squirly if overpowered. Insurance may become a factor, "Operator intentionally overpowered the craft above the design limitation thereby voiding....."

As I posted in another thread a month ago, my wife took my daughters back to the dock from the island on the dinghy. When leaving the marina, heading into about a 12 - 15 knot wind, as she accelerated, she didn't lean forward. The nose rose up and the wind got under the dinghy. It spun her around and she powered up into the rocks of the breakwater. She was shook up, but not injured.

Our dinghy is a 9'6" Achilles inflatable with a hard, inflatable floor and a 8HP Yamaha 2-stroke which is the rated limit. We can take 3 adults on a fast plane (20 - 25 mph).

 

[Turtlesboat]

maybe look at different brands, they differ in the max rating depending on the construction of the transom.

 

[wkearney99]

FWIW, I put a set of tabs on our 10' dinghy (bombard with floor panels and a 6hp Johnson 2-stroke) and it GREATLY reduced the amount of bow rise when accelerating. They're foldable so I don't lose the ability to roll it up for storage. I got them from West Marine: model#: 7780182.

The difference was instantaneously noticeable. They work by extending the flat surface from the transom farther out along the underside of the aft points of the tubes. This has the effect of keeping the tubes from digging in quite as much, and that keeps the bow down a bit more. It pops up on plane a LOT faster than before. It's also a bit more stable when up on plane. I noticed that when up on plane running WOT it tended to cavitate the prop a bit when bouncing. Not unexpected but not something I'd ever dealt with before as the stern was a bit more 'dug in'.

My only concern is how well the pins used in the hinges will stay in place. They're fine when underway, but when folding it there's a slight chance of either dropping one of the pins or having a second one slide out. I'm going to either put a spot of wax into the holes or 'crimp' the plastic a bit with a soldering iron. But overall I've been please with their effect. They seem a bit expensive for what you're getting but they do work.

Truth be told, for the limited amount of use we get out of the dinghy, we'd probably be better served with an 8' model with a smaller outboard. They'd stow more easily and would have enough capacity and power for all of the times we've used it.

 

[sr330daguy]

www.defender.com/product.jsp?path=-1|215570|216220|1252929&id=1252863

 

[fsudelt]

At this point my thinking is i'm going to keep the 8.5 dinghy until after installing the davits (just ordered Hurley 10'' today) and see how it stores on platform. If stores ok and enought rooms I'm not going to do anything. Going down to 7.5 was an option that would of gave of more room, just didnt know there would be so many changes. Thanks for all the input.

 

[barryg]

Good luck with it Brian, and take photos so we can see the install of the Davits, and how the Dinghy looks on.

Barry