Motor mounting options

[Nephroid]

After many years for trailer sailing, I finally decided to keep my DSII at a Marina this year. I have never used a motor for my DSII or any other sailing dinghy but it seemed like a prudent choice given how crowded the marina and nearby waterways can be. Specifically, I purchased a long shaft ePropulsion Spirit 1.0+. That will be a topic for another day as I'm eager to see how it compares to either the Torqeedo or the Electric Paddle.

I've read many past threads about motor mounting options and it seems very easy to make a couple of transom plates to protect the gelcoat. My only concern is that no matter how far outboard of the rudder you mount the motor, it seems you can never fully eliminate the risk of the prop hitting the rudder. Plus you have the issue of moving the thrust far from the centerline of the boat.

The two that I could come up with were:

1. Make a motor mounting plate with pintles that can drop into the rudder gudgeons. They seem to use a similar idea for the RS Quest (https://westcoastsailing.net/rs-quest-outboard-motor-mount-que-ua-103/) On one hand the eliminates any risk of the prop striking the rudder. On the other hand this requires me to "hot swap" the rudder for the motor while underway which doesn't sound like a lot of fun, particularly if seas are rough.

2. The other is to somehow connect the free end of my tiller extension to the outboard tiller. The thinking here is to allow the tiller extension to act as a "linkage" between rudder and motor allowing both to turn at the same time and in theory never come into contact. It also avoids the question of whether to steer with the motor or the rudder as both would move in tandem.

Curious to see what folks reactions are to my ideas and if anyone has come across any other creative solutions.

[GreenLake]

With the CB (even partially) down, the rudder is fully capable of keeping your DS on course, even with a motor mounted at an offset.

There's also no need for a linkage. You should be able to keep your motor locked pointing back (or slightly toed out to support the rudder correction). And then steer with the tiller as usual. What I'm talking here are the parts where you motor in a (nearly) straight line and need little rudder deflection. You'd take any turns a bit wider than you would while tacking the boat, and in my experience you don't have to worry about contact, as long as you don't mount your motor too close. The rudder needs to be able to swing something like +/- 15 degrees from centerline without making contact (rough estimate).

There are some occasional maneuvers in tight spaces where a bit of sideways thrust comes in handy. For those, you can sit well back so that you can operate both motor and tiller at the same time and in concert. That achieves the same results as a dedicated linkage. But you may need to practice this a bit.

The motor you picked is a bit stronger than what I have on my boat (and yes, looking forward to your review) but I've sailed on former forum members DSII with a 2HP outboard, that was also mounted off-center. I had some problems with that motor, but they had nothing to do with the off-center mount. Instead, they ranged from the lack of a reverse gear and inability to start because it became airlocked (and we didn't know the secret trick).

I use a very simple system to hold the tiller in a fixed position, and that system is always deployed when I'm out solo. It allows the tiller to be set to a new angle with ease, but will then hold. This system also prevents most contact between rudder and propeller, because the tiller doesn't suddenly wander.

[Nephroid]

Thanks, GL.

I finally had the chance to mount the motor and take my DSII out for a spin. I did find that no matter how far outboard I mounted the motor there was still risk of unintentional contact with the rudder. It's possible that the electric motor requires a larger than average prop.

Fortunately, I had purchased the long shaft version and as long as the rudder is in the "up" position, there was no risk of contact with the motor. I did most of my shakedown cruise this way and while there was enough friction on my rudder to keep it up, was very nervous it would drop the moment I stopped paying attention. I'm going to work on a simple uphaul/downhaul system which has its own benefits.

Could you please tell me more about the tiller system you mentioned (is it the shock cord one?). The motor does come with some pins that allow me to lock it into the fwd but I would rather retain the option to use it given I'll be manuevering in a tight marina with many other boats nearby.

btw - the Spirit 1.0 EVO runs beautifully. Will offer a more fulsome report shortly.

[GreenLake]

I looked up the propeller dimension and it says 11" for the diameter. The boat is about 72" wide. Half of that is 36". You should be able to find a spot to mount it in those 36" to get enough clearance for 5.5" (half the propeller diameter). I think you found a clever solution, but I wonder at what rudder angle you were running into issues? Did you get contact at less than 30° rudder deflection?

My electric paddle has a very large diameter 2-blade propeller. It seems designed more like an airplane propeller than the typical marine one. However, if I make contact with the rudder, it's never necessary, but operator error on my part. However, there may be a difference in how far back the shaft is. For my motor it basically touches the transom. That makes it easier to achieve separation from the rudder. From the images for the Spirit 1.0, it looks like the propeller simply sits further back.

It looks like your motor requires the workaround you found. Now, normally, I wouldn't recommend running the rudder that way, but you are not trying to balance a sail plan that is trying to round up the boat. So, under motor, there's much less rudder force needed, and tilting up the blade seems like a fine approach.

In my experience, which includes some narrow fairways, it's rare that I need help from the motor angle to turn the boat. However, I only have a friction "lock", which I can easily override in the moment. Nothing like a fixed pin. It's really convenient to be able to rotate the motor back to normal and then not having to do anything to keep it there.

The tiller tamer I use is the shock cord design and it works on the same principle: allows manual input at all times and "locks" the tiller automatically at the last position. Without any action other than letting go the tiller. For that reason, it also works with a tiller extension.

The design is super simple: find a way to mount a nice bungee cord, moderately tightly stretched from port to starboard at or about 6" behind (and underneath) the tip of the tiller. Use 3 wraps of a narrower shock cord to connect the tiller to the bungee. The wraps should be just tight enough to create some friction corresponding to the force needed to hold the tiller. But not more. When you give manual input, you exceed that holding power and the wrap (and tiller) slip along the bungee until you let go. The 6" give you a nice free grip area, and if you have a tiller extension, you put the pivot point for that just forward of the bungee.