Most manageable size outboard motor for dinghy

[Bill O]

Don't know if you are ok w/ a 2 stroke, but they weigh considerably less.
A 8 or 9.9hp Tohatsu/Nissan (same motor base)~52lb w/a manual start. The 9.9 would be the way to go for the heavier RIB. Look around, they are out there.

[Thumbs Up]

The 8 and 9.9 are not the same. The 8 and 9.8 are the same weight. The 9.9, 15, and 18 all weight he same. (nissan tohatsu 2 strokes)

[Mike OReilly]

Haven't read all the posts, but my choice has been a 3.5 hp Tohatsu. I can lift it myself with special gear. And it will easily plane my portabote with just one person in it. It will plane with two adults in flat conditions.

[SailFastTri]

Originally Posted by steffan

I know this is an old thread but I am currently wrestling with this decision. I'm looking at a used RIB tomorrow. It's heavier built than we will need for the next few years of weekend+ trips (150 lbs), with the consequentially larger, heavier motor (120 lbs 15 hp). But it will cost less than a new 80 lb PVC sport boat with a new 60 lb 6 hp motor. Factoring in a crane will probably make it a wash cost-wise, and it will be harder to stow.

I'm sure it'll be nice to have a sturdier tender when it's in use, but a PITA the rest of the time it's sitting at the marina or getting towed (no davits). Am I likely to regret getting into too much dinghy? It should last until we go cruising with a bigger boat in a few years but I doubt it makes sense to size my current dinghy for a theoretical future boat and lifestyle, no?

34 foot boat?

If your primary use is a tender while cruising I'd recommend a light dinghy you can hoist aboard to the fore-deck, or stow, and a ~30 pound 2.5HP Honda/Suzuki you can lift one-handed with a harness to the taffrail.

OTOH get the heavy one if you're looking for a fun ride around the harbor and rarely need to take the dinghy away from your home port. Towing offshore or long distance is a drag (literally).

[Bill O]

Originally Posted by Thumbs Up

The 8 and 9.8 are the same weight. (nissan tohatsu 2 strokes)

Yes, you are correct. Good catch on my typo

[GILow]

Originally Posted by Mike OReilly

Haven't read all the posts, but my choice has been a 3.5 hp Tohatsu. I can lift it myself with special gear. And it will easily plane my portabote with just one person in it. It will plane with two adults in flat conditions.

Please don’t remind me. I sold mine a year ago and sometimes I really regret it.

But I don’t miss the lack of reverse or at least a neutral gear.

[SailFastTri]

Originally Posted by GILow

Please don’t remind me. I sold mine a year ago and sometimes I really regret it.

But I don’t miss the lack of reverse or at least a neutral gear.

I picked up a Torqeedo last year and love it. Fantastic at the dinghy dock because there's no shifting. F/N/R is just a right or left twist on the handle. And if you have enough solar to meet/exceed your average daily needs, or regularly tie to a dock, you never run out of fuel. No need to deal with fuel or oil or fouled carbs/plugs. Easy lifting on/off the dinghy.

The range anxiety thing is the only issue. But I get 8-16 NM range depending on speed/conditions, and can recharge each night from my boat's house bank, which is in turn charged by solar.

Quiet too, we can talk low and the gurgling of the water is the loudest noise our dinghy makes underway.

[Mike OReilly]

Originally Posted by GILow

Please don’t remind me. I sold mine a year ago and sometimes I really regret it.

But I don’t miss the lack of reverse or at least a neutral gear.

True, that is a bit of a pita. But I've got good at spinning the engine around to get reverse. There is a neutral gear with these engines though, which is nice.

BTW, I noticed a typo in my comment. I meant to write:

Originally Posted by Mike OReilly
Haven't read all the posts, but my choice has been a 3.5 hp Tohatsu. I can lift it myself WITHOUT special gear. And it will easily plane my portabote with just one person in it. It will plane with two adults in flat conditions.

SailFastTri: I was really interesting in a Torqueedo before settling on my little Tohatsu. I researched them a lot, and tried one for a short while on my portabote. The power was fine, but if you wanted any speed (like to plane the bote), it drew the battery down precipitously. I figure I'd need at least two, perhaps three, of their batteries to make it work for me.

Comparing cost, and ability to go long distances, and my uncertainty around being able to keep the batteries charged off the dock, I chickened out and went with the Tohatsu. But you've got me thinking again...

Can you describe your onboard charging capacity? How big is your solar collector? And what size battery bank do you run?

[slug]

Originally Posted by epiic

I need to order an outboard motor today for my new Zodiac Cadet 310 Rib.

I would like a 8-9.9hp 4-stoke but I can't imagine how I am going to lift it.

Because of this, I am forced to purchase a smaller motor 6hp 4-stoke (57lb).

The 6hp would be the maximum I could lift in/out of the dinghy and onto the transom mount.

Any tips to manage a larger outboard without having to purchase a crane would be greatly appreciated.

Look around for a two stroke 8 to 9.8 used from an outboard repair shop

They weigh about 28 kg

That’s about max for human grunting

Another advantage to a lightweight is that they maintain the self bailing floatation level of most 3 meter size ribs

[Pete7]

Originally Posted by SailFastTri

34 foot boat?

If your primary use is a tender while cruising I'd recommend a light dinghy you can hoist aboard to the fore-deck, or stow, and a ~30 pound 2.5HP Honda/Suzuki you can lift one-handed with a harness to the taffrail.

OTOH get the heavy one if you're looking for a fun ride around the harbor and rarely need to take the dinghy away from your home port. Towing offshore or long distance is a drag (literally).

I was thinking exactly the same. Standing in a wobbly dinghy passing or lifting even a small outboard up to the pushpit is tricky with waves or passing traffic, but the little 2.5hp engines are a one arm lift. Our little Honda 2.3 is a hoot to drive and quite entertaining, for everyone else. But pushing the inflatable we do eventually wind our way to the shore. Nice thing is no water pump or mixing fuel needed and a big carrying handle on the front for climbing up the transom.

A big dinghy and heavy outboard is a lot of weight on the stern of a 34ft yacht.

Steffan, great picture in your image library, shrink it and add it in your settings as a profile picture.

[slug]

The micro engines have internal fuel tanks

This can be a problem

The next class up have external tanks

Also the 8 hp.class and perhaps smaller, I don’t know all the motors , output 12v dc when running

This is critical if you intend to illuminate, running lights , your tender at night to prevent being run down and to comply with the law

[Boatguy30]

The new Suzuki 6 is about 52 lbs. Making it the lightest. Have had mine a few months. It seems to possibly have a bit less power than a Tohatsu, but also has an oil filter so I think overall it's a better engineered motor and the carb is I believe a simpler more reliable design.

Also have a 2 stoke 3.5 Tohatsu for the spare dinghy/backup.

[Bill O]

The motor selection will depend on how you want to use the dink, the size/ how heavy of a rib you are getting.

If you are just hanging out in a harbor going between the boat/dock, the a 3.5 or even a 3 hp equiv. Torquedo will be fine for 1-2 people. Start loading it down w/4 people or 3-4 5 gal jerry cans, you'll find that that small of a motor will be barely enough.
If you want to explore things further away, an 8 or 9.8 w/an external tank will be ok for 2 people. A heavier 10' rib may need 10-15hp to get up on plane with more people or more gear (dive tanks).

If you have the room, it would be ideal to have 2 OBs. One small and a larger one for exploration. Do like the Torquedo (but expensive) as you can store it below decks w/no gas fumes and leave the other locked on the pushpit.

[SailFastTri]

Originally Posted by Mike OReilly

snip

SailFastTri: I was really interesting in a Torqueedo before settling on my little Tohatsu. I researched them a lot, and tried one for a short while on my portabote. The power was fine, but if you wanted any speed (like to plane the bote), it drew the battery down precipitously. I figure I'd need at least two, perhaps three, of their batteries to make it work for me.

Comparing cost, and ability to go long distances, and my uncertainty around being able to keep the batteries charged off the dock, I chickened out and went with the Tohatsu. But you've got me thinking again...

Can you describe your onboard charging capacity? How big is your solar collector? And what size battery bank do you run?

Hey Mike - To answer your questions:
"if you wanted any speed (like to plane the bote)" The Torqeedo isn't for you if you want speed and range. Choose one or the other. I moved to the Torqeedo from a Suzuki 2.5 (I still have the Suzuki as backup but I'm thinking of selling it). I gave up on the planing idea when I downsized from a 9.8 to the 2.5 in favor of lifting ease. I can get from here to there at 2.5-3 knots and my wife and I are (mentally) over the need to zoom around (yes I know "fast is fun", and someone will have a story about how they beat the downpour while returning to the boat, or something like that).

The extra Torqeedo battery weighs more than 10 pounds and is expensive. If you need to bring spare Torqeedo batteries it diminishes the weight advantage and the cost is prohibitive, as you noted.


"Can you describe your onboard charging capacity? How big is your solar collector? And what size battery bank do you run?" I have 370 watts of solar, a 200+ AH AGM house bank (3x Group 24), and my refrigerator (my biggest power hog) uses 3.2A and its compressor is cycled on more than off. The Torqeedo draws 4A when charging, but is usually not more than a few hours at a time). I also have the usual marine electronics, all lights LED, and laptops/phones/tablets etc. I never discharge the house bank below 12.1v.

On a sunny day we are generally back to full charge by 12-1:00 PM, or a cloudy day we might not fully charge but reach 90% by late afternoon.

The Torqeedo 12v charge cable draws about 4 amps, and you can do the math to figure out how long the recharge takes depending on how low the battery is. (AH=watt-hours/12, I think?) I don't worry about it - I just remove the Torqeedo battery when we're done with it for the day, plug it into 12v and it's charge by morning. We rarely go more than about 5 miles per day in the dinghy, at <3 knots so I don't draw it down fully.

[Mike OReilly]

Bill, engine and dink choice also depends on the size of the mother ship. Some of us don't have the option of going big.

Originally Posted by SailFastTri

Hey Mike - To answer your questions:
"if you wanted any speed (like to plane the bote)" The Torqeedo isn't for you if you want speed and range. Choose one or the other. I moved to the Torqeedo from a Suzuki 2.5 (I still have the Suzuki as backup but I'm thinking of selling it). I gave up on the planing idea when I downsized from a 9.8 to the 2.5 in favor of lifting ease. I can get from here to there at 2.5-3 knots and my wife and I are (mentally) over the need to zoom around (yes I know "fast is fun", and someone will have a story about how they beat the downpour while returning to the boat, or something like that).

You've seen my tag line right? I usually don't fret about speed. But sometimes it's nice to have.

Actually, it's the same issue with my 3.5 hp. I can move along at 3 knots for a long time on the little 1/2 litre built in tank. But if I push it to plane, or even just a lot faster, I drain the tank in a short time.

But I can't see not having a spare battery available. I always carry a small jerry can of gas in the dink when we go off, and sometimes have had to refill underway. I don't think the extra weight matters. But the cost sure does.

How about longevity of battery life? Have you had to replace yours?

Originally Posted by SailFastTri

I have 370 watts of solar, a 200+ AH AGM house bank (3x Group 24), and my refrigerator (my biggest power hog) uses 3.2A and its compressor is cycled on more than off. The Torqeedo draws 4A when charging, but is usually not more than a few hours at a time). I also have the usual marine electronics, all lights LED, and laptops/phones/tablets etc. I never discharge the house bank below 12.1v.

On a sunny day we are generally back to full charge by 12-1:00 PM, or a cloudy day we might not fully charge but reach 90% by late afternoon.

The Torqeedo 12v charge cable draws about 4 amps, and you can do the math to figure out how long the recharge takes depending on how low the battery is. (AH=watt-hours/12, I think?) I don't worry about it - I just remove the Torqeedo battery when we're done with it for the day, plug it into 12v and it's charge by morning. We rarely go more than about 5 miles per day in the dinghy, at <3 knots so I don't draw it down fully.

That's great info. Thanks . Our boat's charge and power system sounds similar to yours. We have 400 watts solar (and a 400 watt wind gen as well). Our biggest single draw is our fridge, which after a recent upgrade now draws the same as yours. My house bank is theoretically 320 Ah, but I bet it's lower than that now that the batteries are getting a bit old. Still, it works fine for us.

So... now I'm really intrigued. If I could just find the spare boat bucks. The cost may be the real downside.