Transom mount on sailboat. Too shallow?

[Dorsilfin]

I replaced a 1980's era motor mount on my sailboat with a new mount. This mount is much more stout and I'm quite pleased with its setup vs the old one.


I followed the instructions and everything looks good. I put the boat in today and while this setup works 100% fine in calm water. however if I moved to another part of the boat, the outboard stopped sucking water and sounded like it was out of the water. I feel like the least bit of rough water and I'm going to be in trouble trying to push through chop with such a thing margin of "okay" to out of the water

When the boat is without anyone on it. the motor sits with the plate just skimming the surface. The water pickup and exhaust seem to be right above the plate





When I'm sitting in the stern running the engine and moving the engine does sink a bit into the water




Id hate to rip it all apart. but after today i'm already putting tools together to pull the motor and the mount while the boats in the water and trying to move it down at least an inch if not two. Can the motor be too deep?

[Adelie]

Outboard on a sailboat is not like on a dinghy, the sailboat doesn't plane. You want the motor head out of the water at full throttle when the boat is pulling a big stern wave.

So what I would do is stand at the front end of the tiller with somebody in front of me and crank the speed up to full. I would tape my iPhone to a stanchion aimed at the motor prior to this and start recording a movie. That will give you an idea of where the top of the wave is relative to the motor before you change anything.

At full throttle I'm used to seeing the top of the stern wave more or less at the bottom of the bracket plate the motor is mounted on. At full throttle it's not drowning, and at low revs the prop and ventilation plate are still in the water hopefully.

Based strictly on the way I'm interpreting your description I wouldn't drop it an inch or two, more like 6 or 8.

If the mount has a square bolt pattern you can drop by the vertical separation of the bolts and only have to drill 2 new holes instead of 4.

[Redpcx]

I concur with the recommendation of 6 0r 8 inches lower.
If the engine sucks at all in calm water, it will suck a LOT, over rev, and jerk on the bracket a LOT in rough water, or when heeled. Yes, your boat WILL heel when motoring, with no sails up.
Long shaft motor has the flexibility to keep the prop in the water and keep the powerhead above the water in bouncy conditions.

[Dorsilfin]

Thanks for the feedback. i'm heading to the marina shortly.

Its got a mostly uniform hole pattern on the back so I should be able to drop it 2 holes and then re-drill the other 4 out. 6 on each side, with a gap in the middle.

The kicker mount is adjustable up and down so really I'm going to heed to the advice of alot lower. I can always kick it up a notch or two in calm water.

[thomm225]

See attached. The water line is right at or just below the black boot top .

So the motor is down in the water on this setting (4th down) maybe 12"-15".

In 4'-5' steep bay waves, it can still come up out of the water should I happen to start the engine before entering the creek but usually my motor stays in the water

Also, I usually have it in the 3rd hole down. See picture on the lift.

The video (not very clear but) shows the motor down and running in some decent sea. I was motoring in calm water and a cloud line passed over and brought with it wind and waves. This is after it has passed and I already have the jib back out. Autopilot is doing the driving.

https://www.youtube.com/watch?v=Jz9x5oRthfk

[sailjumanji]

Are you using a long shaft or XL shaft motor?

[thomm225]

Originally Posted by sailjumanji

Are you using a long shaft or XL shaft motor?

25 " Extra Long Shaft. (2011 Mercury 5 Hp 4 stroke Extra Long 25" Shaft)

Yesterday I was motoring in the creek against the tide and wind (14 knots or so) on 1/2 throttle at 4 knots. Best speed seems to be between 1/2 and 3/4 throttle. The prop is the standard prop

I sometimes mount the outboard on the stern railing dinghy motor mount for maintenance. If you were sailing long distance that might be a good spot for it if you wanted it totally off the bracket low down near the water

[Dorsilfin]

Well I had a successful morning. Ended up moving it down 6 inches and lining my top 3 holes with the bottom 3 from prior. That gave me 6. I'm going to re-evaluate at the end of the season and possibly drop it a few more. I've got enough in the water for the sailing areas I sail out of.

Going to need to do some sanding and painting on the transom tho. Looks like a hot mess right now.



I only ran 1 of the bolts through the bottom section as they were easiest to drill. Ill see about trying to tape the others but its difficult hanging off the back of the boat.