Dinghy Ouboard Size Question

[Mike G.]

I currently own a Zodiac 310 RIB and have a Merc 4 HP outboard. It is fine for my purposes and fairly easy to handle. However, my almost 13 year old needs a little more to keep himself occupied when at the mooring or on the hook. I am thinking of getting a larger outboard - maybe in the 8 -10 HP range. That should be more than enough to get the dink up to plane.

My question is weight and size on the pushpit. Do you think that it is too large? I am not worried about the weight to lift as I have a really nice Garhaurer engine hoist (purchased from one of our respected members on this site).

This is probably the best time of year to find one at the right price on the used market. If you all think it is not to large, I start looking.

Mike

 

[AXEL]

As far as I know your dink should have a spec plate mounted on the transon with the max hp capicity. If you can't find it try contacting your local Zodiac rep, they should be able to tell you. You don't want to exceed the max hp. An over powered dink can easily flip with to much torque.

 

[Tim R.]

I have a Mercury 290(rib) that is about 150 lbs and a Johnson 2 stroke 4hp twin. I can get it up on plane and I weigh 200 lbs. The OB only weighs 33 lbs, has a self contained tank and a remote tank connection.

If you get anything more than a 6hp, your son will fly. I have a 12ft aluminum row boat with a Mercury 8hp and it is scarey fast. The OB must weigh 80 lbs.

 

[Capt. Kermie]

How much can YOU lift?

Be careful about buying an engine you can barely lift yourself since at some point you will have to manhandle it on your own. If you can get your hands on one of those older two stroke Nissan 9.8 engines you would be just under 60 lbs which is the maximum weight you will ever want to struggle with and still excite a 13 year old. The newer 4 stroke engines are quite heavy and you'd be hard pressed to get any decent horsepower under the 60 lbs limit, which also limits how much HP you can purchase.
I am a very big guy who used to be a hobby bodybuilder and I can attest to just how awkward and difficult it is to lug a 60lbs 5Hp 4 stroke Honda on and off a dinghy.

 

[Mike G.]

Thanks for the fast responses. the Zodiac 310 is rated at up to 15HP. I think it is about 125 lbs. MY 4HP 3 stroke is pretty slow. It can not get it up to plane. After reading your response, maybe I will borrow some different sizes and see how they handle. I want the kid to have some fun, but he does not need a Cigarette boat!

When he was about 6 years old, we used to haul him around on a tube. He thought it was fun, but it certainly didn't go very fast.

Back to the original question: How much do you think the stern rail can handle?

Mike

 

[Mike G.]

Re: How much can YOU lift?

I hear ya on the weight which is why I got the lift. It was near impossible for me to lift the 45 lbs until seas were dead calm. The Garhauer hoist is incredible. I was hoisting it with my teeth because I couldn't reach the cleat at the top of the unit, but Garhauer now offers a cleat on a ring which slips onto the bottom of the pole.

 

[ITMaster]

Something Seems To Be Stange Here Mike

I have a Zodiac 310 with a Merc 4 Stroke 4 Horse for my dink. I tip the scales right at 210 lbs. If I get in the right location in the dink, I come up on plane without a problem and will boot scoot right along

If I sit back in the rear of the dink or if I sit up on the pontoons on the either side, I will not get it up on plane. I have to sit in the middle, toward the front for it to come up. I can also get it up with my wife in the front of it, but I still have to shift the weight forward. Getting up on plane requires that I get the dink balanced properly with distribution of the weight.

I have a Boston Whaler with a 50 Horse, and the same thing applies. If she and I both sit back at the stern and hold the throttle wide open, it will not get on plane under any circumstance.

The obvious, I would presume has been checked. Good fuel, plug in good condition, proper inflation for the pontoons, no water in fuel, right angle and height of the motor relative to the boat, etc., etc.

 

[sailingdog]

Mike, just curious, where'd you find a THREE-stroke engine???

 

[Rich (P303)]

Your push-pit will handle it... as it will probably be mounted at a stanchion. The only place you need to worry is at the stanchion connection to the deck. I think it is a matter of the quality of your push-pit and/or backing plate and/or deck construction. A lot of wobbling back and forth... will not be good. How about beefing up the backing plate with more surface area if you are worried?

I have a small Avon RIB with a 4HP Yamaha 4-stroke. It ain't exhilarating with 250 lbs. sitting on a tube. It is enough to get us thru the current out to the boat... but that is about it. Not anyways near getting up on plane.

Why not leave it on the dink? Get him a spear-gun!

Your call.

 

[Mike G.]

My 3 stroke engine? Ha, Must have been drinking !!!!
I am surprised that no one else nailed me on that one.

 

[petersea]

Zodiac 310 engine size

Mike, I also have a 310 Zodiac like yours however I have a 9.9 Yamaha (2 stroke) engine. This thing will "FLY" with just me in it (215 pounds) and even with two adults it will still move fast. Just my opinion but you may want to get the bigger engine and somehow limit the throttle so that it does not get full throttle, especially if the 13 year old will be by himself or maybe one other. I actually thought the 9.9 was a little much at full speed but very good if not using more then 1/2 to 2/3 throttle. It will JUMP on plain with that engine even with two people and a load. I say all this based on a "normal' 13 year old and the need for speed and adventure, now maybe your kid may be the more responsible type and be OK with it, your call. If I remember correctly the mfg spec plate calls for max 15 hp engine (double check that) but in my opinion that is way to much, get the 10 and limit the throttle to what you think is reasonable OR get the eight hp, might be a better fit but I don't have any first hand experience with that set up. I always think bigger is better just you don't have it use it all but nice to know it is there if and when you want it ! If you are thinking about a 4 stroke remember they are a little bit heaver and may not be as responsive on the throttle but I still think they will do just a well as moving the dink at comparable speeds.

 

[petersea]

another thought

came to me, Mike, if you are looking for a used engine make sure it is new enough to have a safety switch and lanyard and make sure the 13 year old uses it ! ! I remember an incident several years ago right here in Noank where a couple of young kids hit a boat and a woman got injured all because of horse play and both the kids were thrown from the dink with it still operating very fast in a very small circle around them. Make sure the kids use the lanyard !

 

[Stu Jackson]

At the risk of answering the original question: http://www.c34.org/projects/projects-outboard-mount-heavy-duty.html

 

[Mike G.]

Re: another thought

Pete: Advice well taken. We keep a pretty good eye on him and he always has the lanyard. In Noank, he is only allowed to go to the dink dock and mooring. We are the first mooring as you enter the river. It is pretty dangerous with all of the traffic. In fact, I have asked to move in a bit next year as the Stink Pot wakes are brutal.

A couple of years ago I was down below pouring cocktails and heard a bunch of screaming. Came running up and saw two young girls in a dink yelling for help. Their outboard on the inflatable had fallen off of the transom. One girl was hanging over the transom trying to keep it dry while the other was panicking. The tide was moving fast. My outboard was on the rail so I rowed like a madman to catch them. Finally got close enough to tell the panicky one to grab the next mooring. I towed 'em back to the dock (rowing against the current), not even a thank you from the parents!

BTW, I was there at lunch today. I will tell you why on my next Post. Went over to the dink dock to check on things. Wow, it was quite a blow! It was tough keeping my feet under me.

Mike

 

[Rich (P303)]

Very good Stu... What question?

 

[Stu Jackson]

If the pulpit can hold up the outboard motor.

 

[larryw]

Before you buy another outboard, put one of those prop shrouds on your 4hp. Those things are good for about a 30% gain in thrust and they act like a Dole-Fin, making it easier to get up on plane and stay on plane at a slower speed

 

[Tim R.]

Larry, do you have first hand experience with the Powerthruster? Do they really work on a 4 hp OB? According to SBO they are for 6hp and up. Their website states 5hp and up. I would like to find out to see if it is worth the money. They are not cheap.

 

[Rich (P303)]

I have to lose 50lbs... get a bigger engine... or that nuclear prop thing.

Please advise.

 

[RobG]

Hey Mike G. small world.

We're down there on mooring G-1. I'd love to share cocktails next season! :dance: Moving into the mooring field further will get you away from the action a little more but not the wakes. They seem to be just as bad where we are. I want to campaign for a larger no wake zone. Let me know if you're interested.
I have an 8hp 2cycle OB and it is a beast to handle. I'd consider a 6hp 2cycle with the Power Thruster attachments as they do make a difference (can't say 30% though), who would know? All in all a 6 seems quite a bit easier to handle than an 8.
Mike & Tim, I have the Power Thrusters on my 8. They are very thick polished SS so they will add some weight to the "light end" of the motor. I installed them for some level of safety as a prop guard as well as whatever efficiency they would add. I thought I saw a small "dinghy" version of them on the web site?
See you around the Shipyard,
Rob