Which outboard for rollup dinghy + where to store it on single-rail stern railing

[SailorElliot]

Hey,
I'm buying a small outboard (~2.5hp) and I need a place to mount it while cruising. I've seen the Edson mounts but my stern pulpit only has a top rail and therefore isn't compatible. I've included a photo below (sorry for the odd photo, it's the only one I have.)

My second question is which outboard to get. I have the West Marine RU-250 roll-up dinghy and it's pretty much a non-planing dinghy due to its keel-less design although I weigh 130 so I might be able to plane it with just myself. My main consideration is weight as I have to hand down the outboard to someone on the dinghy, which seems impossible with over 40 pounds. It's pretty much between the Suzuki 2.5 and Honda 2.3 and I'm leaning towards the quieter, water-cooled, cheaper, and lighter Suzuki but I could be easily persuaded. Also if I get a good enough argument I might spend $1500 on a used electric outboard.

Thanks for reading.

Elliot

 

[Ralph Johnstone]

Use this design as a basis but run the centre tube down to the gunwale:

It can all be made with SS tubing fittings and no welding required.

 

[SoSound]

I did exactly what @Ralph Johnstone suggests, never had any issues at all, maybe the quickest boat project ever. At the time that I built the outboard mount, I had a Lehr 2.5.

On the inflatable and outboard, I currently have a Saturn SD230 and a very lightweight battery outboard that we have had for several years. I’m not setting and retrieving crab pots in neighboring coves, and I don need to get up on plane. I think lighter is always better for the outboard, and I can handle our EP Carry myself with one hand.

edit: forgot to mention the Lehr…

 

[31seahorse]

To move the outboard motor to the stern rail is an additional consideration. For our short adventure in cruising we installed a Forespar motor lift on the transom so lifting the motor from the transom of the dink, then into the dink, and finally to the stern rail was not a "clumsy ballet" for me as I stood in the dinghy. Admittedly, age might have been a complicating factor for us.

Additionally, neutral is a wonderful addition to any motor (or "off" for the electric OB). When starting a gas OB, which might require using the choke feature, the motor will run at higher than necessary rpm for a short time and without neutral your dinghy will be "off to the races" before you are completely ready to move.

 

[dlochner]

The Edson motor mounts are nice, but excessively expensive and won't work for you. If you don't want to make your own, as @Ralph Johnstone did, Sea-Dog makes one.

We have an electric outboard and in some situations it is a good choice. If the boat has the electrical capacity to recharge the battery and the dinghy runs are always short (1 mile or less) an electric outboard will work. The battery on our Torqeedo is 910 watt-hours and takes 8=10 to fully charge. Refilling a 2.5 hp outboard takes minutes.

Sea-Dog Stern Rail Bracket for 2-Stroke Outboard Motors

Sea-Dog® Stern Rail Bracket for 2-Stroke Outboard Motors Features: Bracket designed to hold small 2-stroke outboards up to 8 HP upright on stern rail Will fit 7/8" and 1" rails as well as rails using 90° tee fittings 2-Piece unit is m

www.defender.com

 

[Brian D]

The problem I had was no mount would work on my stern rail. So, I built my own out of a couple pieces of ply. It holds my Suzuki 2.5 just fine. I use it on a Mercury 220 Rollup inflatable. The motor is quiet but still loud.

 

[SailorElliot]

Use this design as a basis but run the centre tube down to the gunwale:

View attachment 208613 View attachment 208620

View attachment 208621 View attachment 208623

It can all be made with SS tubing fittings and no welding required.

So the metal bar would just be rubbing against the gunnel or fastened to the gunnel with lines? Another idea, using your logic, is the picture below. The dashed square is unusable space (the left side of the traveler in the picture above orientation)


.

 

[SailorElliot]

The problem I had was no mount would work on my stern rail. So, I built my own out of a couple pieces of ply. It holds my Suzuki 2.5 just fine. I use it on a Mercury 220 Rollup inflatable. The motor is quiet but still loud.View attachment 208633

Can you send a picture from the other side? That looks like it might work on my setup.

 

[SailorElliot]

I did exactly what @Ralph Johnstone suggests, never had any issues at all, maybe the quickest boat project ever. At the time that I built the outboard mount, I had a Lehr 2.5.

On the inflatable and outboard, I currently have a Saturn SD230 and a very lightweight battery outboard that we have had for several years. I’m not setting and retrieving crab pots in neighboring coves, and I don need to get up on plane. I think lighter is always better for the outboard, and I can handle our EP Carry myself with one hand.

edit: forgot to mention the Lehr…

I like the weight and price of the EP Carry, but using its boat speed calculator mine says it would push my dinghy 3.7 knots at full throttle which isn't fast to say the least.

 

[Ralph Johnstone]

This goes on the bottom of the vertical tube for rock solid mounting on the gunwale at any weight. Couldn't find the base fitting without the fancy spring as shown below. The pin has a small ball retainer. I have four of these fittings to mount my dodger top the cabin top.

 

[SailorElliot]

I just stumbled upon this on a craigslist Bavaria 820 ad and this looks like it could work too.

 

[Ralph Johnstone]

Not so solid, but still useable for the bottom of the vertical tube.

 

[SailorElliot]

Not so solid, but still useable for the bottom of the vertical tube.

View attachment 208638

I see how this could work but I'd highly prefer not drilling anything into the hull.

 

[31seahorse]

I see how this could work but I'd highly prefer not drilling anything into the hull.

Modify the size/shape of the rail mount in the picture you posted. Looks like a winner with no drilling! Does not need to be that exact shape nor that large.

 

[Ralph Johnstone]

I'd highly prefer not drilling anything into the hull.

Just three screws into the gunwale and sealed. Or two screws if you use the pinned base. Also, you've got too nice a boat for a:

Maybe for bass fishing in a slough, but not on a boat like yours .

 

[Ralph Johnstone]

I've drawn this on the side of your boat but it looks as if you may be able to fit it on the stern.

 

[SailorElliot]

Yeah, that seems like the most practical and solid idea yet. Thanks. If anyone has other ideas feel free to let me know because I won
t start building for a bit. The second question is gas or electric as well as hp/kw. Any thoughts? Thanks again for all of the replies, it really helps my thinking and I'm truly thankful for this community.

 

[dlochner]

Yeah, that seems like the most practical and solid idea yet. Thanks. If anyone has other ideas feel free to let me know because I won
t start building for a bit. The second question is gas or electric as well as hp/kw. Any thoughts? Thanks again for all of the replies, it really helps my thinking and I'm truly thankful for this community.

2-3 hp gas.We have both gas and electric each have strengths and weaknesses that are complimentary. Gas however is more versatile and has a longer range. Electric will take you a long way very slowly or a very short distance quickly. The other day I the dinghy across the marina maybe 200 yards at top speed and used 5% of the battery’s capacity. With gas you can carry an extra can of gas to refill along the way and afford the gas. Batteries are really expensive so carrying an extra battery may be cost prohibitive.

 

[Brian D]

Can you send a picture from the other side? That looks like it might work on my setup.

Not going to be at the boat for a couple of weeks. I also don't have an image from the cockpit. But I cut out channels to fit the vertical and horizontal part of the rail. Then used U-bolts to secure the block of wood to the rail.

 

[RoyS]

My vote is for a small air cooled engine. No salt water flushing issues and no impellers to replace. My roll up is powered with a 2.5 HP gas engine and I have seldom gone much above idle. There are usually two adults and a dog crammed in there. If I attempt to go faster water splashes over the bow. Still faster than rowing.