Outboard Motor Questions

[itsmeken]

To be completely safe and fun while teaching my grands how to sail I need to add an outboard motor to my DS1. The original owner gave me the original motor mount so I plan on using it. However, I have the following questions since I have never done this before:

1. Can anyone provide best installation location information in the form of measurements? Perhaps from the top and center of the motor mount is best? Below is the my motor mount.

2. I have two motors available currently to purchase. Both are 4 Strokes. One a Honda 2.5hp and the other a Suzuki 2.5hp. They are 31lbs. and 29lbs. respectively and fuel tank is on the motor. Both are short shaft versions. Will the short shaft (15") be the best choice or should I be looking for long shaft versions? While I want them to work well I don't want them to be dragging when not in use and in their most upright position.

3. What is the best/safest way to mount this? Should I use some backing material for mounting it (that's my assumption, to distribute the load)?

4. What is the best way to get the mount "level"?

5. Anything else I should be considering?

NOTE: I know some will say go with a high end electric. I'm not ready to dish out that kind of cash as this is an experiment that could be short lived. Not everyone takes a liking to sailing as we all know. In both cases I can get these motors for under $500 and they have very few engine hours on them. They are lightweight, even compared to the high-end electrics and can be stored on their side without fuel or oil leaking.

Thank you for your help!

[GreenLake]

Ha! I see what you are doing. You tried to pre-empt a common reply.

Normally I would say get some motor used, even electric, and sell it used, and that's the way you don't waste as much money if you are going to buy new and then abandon your new hobby.

Ideally, the motor part of an electric motor should retain its value; it's pretty hard to 'ruin' them via poor maintenance, because they require none. But I've not found any good listings to check on that theory. Which may point to all owners being so fond of theirs that they never sell

My assumption would be that you'll need the long shaft, unless long and short vary a lot between types / models of motors.

For 2.5hp you don't need a motor mount - assuming that you have the "motor well" at the back of your boat. By all accounts it should be good enough to mount a motor that size. The advantage would be that you don't add to the "lever arm" for the motor weight. The 2.5hp motors are pretty light, but you make any weight at the stern worse by moving it further back.

I've always used two thin strips of 1/4" plywood with some felt backing to go between the metal of the clamp and the hull. It helps further distribute the load and prevents marking of the hull. Alternatively, you could glue two pieces of sacrificial plywood in place with epoxy and treat them with a oil preservative. (Oil because you can easily touch up scratches and gouges).

Even this should be easier than fixing a motor mount.

[itsmeken]

Thank you for the reply Green Lake. I should have specified that my questions are a result of not having a motor well which forces me to install a motor mount.

[GreenLake]

Ah right, yours was one of the earlier ones. (Just looked up the picture of your plate in the gallery). But if you have no motor well, then the next question is, does yours still have the flotation tank in the back or is the transom accessible?

[itsmeken]

Here's a photo of the transom of my DS1

[GreenLake]

I would need to see it from the cockpit side.

[itsmeken]

It's completely enclosed and watertight. I have access ports to allow me to get to the transom for mounting.

[GreenLake]

Have you opened the access holes and verified that you can indeed reach in?

Issues might range from finding the space filled with blocks to difficulties lining up your arm for maximum effect. Best to check that out before you commit.

Motor questions are generally discussed in the "Miscellaneous" section. You may spelunk there, or try search to find whether anyone else ever discussed motor mounts. I'm sure I've seen some discussion but read past it.

[itsmeken]

Yes, through the access ports I can reach all areas of the transom. If this post is better placed in another section, as an admin please move it there and perhaps others will share their experiences adding a motor mount. Thanks.

[GreenLake]

Thanks for the confirmation.

For positioning I can only add general considerations. The lateral offset should be as small as possible - consistent with not letting the rudder hit the propeller. The fore/aft offset of the motor mount and the propeller size, and how it swings when you turn the motor all enter into this geometry.

The height needs to allow you to tilt up the motor enough to get the propeller out of the water. I don't know whether the space between the mount and the transom is enough to make a difference, or whether height relative to the deck is the limiting factor.

Many DS owners who have motor mounts have a DSII style transom which is essentially just a board. So anything hanging over it doesn't meet a deck.

Are there mounting instructions on websites for your preferred outboards?

You asked about backing. Given your access, you should be able to fit some strips of (ply) wood. My recommendation would be to coat those on all sides with epoxy and glue them in place. After drilling, make sure to seal the insides of the holes the same way. Protected from moisture this way and out of the UV those backing strips should last.

One question I don't understand is what you mean by "level"? What complications are you thinking of?

[itsmeken]

Thank you for the reply. Your considerations mentioned are my concern and reason for my original post. By "level", I want the three mounts to be mounted such that the top edge of the motor mount is parallel to the boat's level position. However, I believe if I snap a chalk line from bottom edge to bottom edge of the transom deck that should provide a level line to work from. Thank you again for your replies.

[GreenLake]

You sound like you got that.

[mcqmga]

I have the "motor well" DS1. I am thinking of buying a small 2.5 Suzuki . I'm concerned about securing the motor using the well. I read where it was suggested using 1/4 inch laminate glued to the boat where the motor clamps touch the boat. Is there any other "methods" used to secure outboard?

[GreenLake]

What kind of reply are you looking for. You'll find any solutions here, including a traditional motor mount.

I've been using plywood shims for the motors I have been using (all electric, but I think the issues of clamping to the motor well may have a generic component).

One motor made it feasible to glue the plywood to the inside of the motor clamp and then pad it with felt. The wood prevented the clamps from scratching up either hull or motor well and distributed the point loads a bit. The same design didn't work with the next motor. For this one, I taped the plywood together so the two pieces form an inverted U shape with a bit of tape forming the top. I hang that over the edge of the well, and the clamp then goes over that.

Again, no damage to transom or motor well.

I could have just as easily glued the plywood directly to the transom (and the inside of the motor well) but then would have had to protect it somehow. Oil would have been the method of choice for easy touchup. Felt isn't as suitable for non-removable pieces.

As long as you can distribute the point loads a bit, and have a mounting surface that either prevents or hides scratches, I think you should be fine with using the well for the size motor you intend (I'm extrapolating a bit, because what I've used is a bit less powerful).