I'm a first time boat owner of a new to me 78 C16. I found a second hand Yamaha F4 at a good price and bought it. It weighs about 60 lbs with the tank empty. I looked though past posts about outboard power and weight but didn't see much written about whether something like adding an oversized backing plate behind the motor mount would be needed? My main concern is that putting that much weight on the end of a lever on a transom likely not designed for it will deform/damage the transom over time and use. Thanks for any info.
With proper backing, the stern should be able to handle that weight. A concern is that some C-16's from the seventies (I'm not sure of the exact year models) are wood cored. If your's is one of those, any deterioration in the core (i.e. rot) would make it weaker.
With the standard motor mount, I don't think that the springs would be strong enough to assist in lifting and lowering the engine. Without a heavy duty motor mount leaning over the stern raising & lowering 60 lbs. would not be fun.
mike
Thanks for the input Bramble. When you say "proper backing" do you mean additional or that which is existing? The mount looks to be original install (I'm assuming they shipped with them.) I haven't spent anytime yet tapping on the transom to try and figure out if it is sound, but I'll certainly be doing that before clamping the motor to the lift.
Take this for what it's worth, as I am no expert on this issue. I suspect the boat will hold the motor just fine. That isn't the issue. The real problem is that much weight aft adversely impacting the pointing performance of the boat. When I sailed my 16, we always moved forward in the cockpit when sailing upwind. I had a Honda 2hp, weighing about 30 pounds.
geeman,
often motor mounts are through-bolted with only a large washer on the inside. A solid backing plate of wood or metal distributes the load over a larger area.
I second what MHarday wrote. 60 pounds on the stern will cause issues with trim.
mike
MHardy and Bramble - thanks for your input. I wonder if loading 30 pounds or so of weight in the bow area would take care of the trim issue. Thirty pounds of sandbags fit in a pretty small area and aren't likely to shift far even if I rock and roll abit. Is this a dangerous or stupid idea?
I don't think that it is either stupid or dangerous, but I'm not that knowledgeable regarding trim issues, so I defer to those more experienced than me to weigh in on the issue.
mike
Today I checked the transom and the attachment of the motor mount. The transom appears to be solid fiberglass about 1/4 inch thick. The motor mount is through bolted with 6 bolts. There is an aluminum backer plate approximately 8 inches square. It does not appear to be laminated to the transom, but the whole of the thing seems sturdy. Is there a way to determine what the transom will support at the point that the mount is attached? I'm sure there is a way to calculate this, but don't know how.
geeman
that sounds like a very good mounting.
Your stern should handle that weight
mike
Thanks Bramble. Gonna remove the mount in the next couple of days, re bed and remount it after testing to see how the mount itself handles the raising of the motor. It presently has one spring attached around the lower pivot. I have another spring and it seems to me that if I add it to the upper pivot, it should increase the amount of weight the mount will lift. Might not need to do anything, the mount seems pretty stiff when I raise and lower it by hand.
I plan to toss a couple cases of water bottles in the bow to counter my weight and the 55# motor.
Easy to install and remove for winter.
Ron
Good thought. How does your 55 pound motor effect your sailing/boat trim? And sounds like the weight on your tramsom is not an issue from a structural standpoint?
Geeman, my personal ballast has much more effect on trim than the motor (LOL).
Our first Compac 16 had oars , one day the engine wouldn't start so we pulled the engine and fuel tank off the boat and oared the boat out of the marina , it was suprising how much nicer the boat sailed without that weight .
If I could find a ramp that was lightly used so as not to be in the way when trying to launch and load I would like to try sailing without auxiliary power, but I don't think it's gonna happen. I'm in eastern NC and ramps seem to be pretty busy when I visit them.
I sail with a Tohatsu 6hp 55 lb motor on mine and the only negative I can say is that water comes in the back when under throttle and it is hard to get the motor out of the water when docked with the springs not much help at that weight. Adding weight to the front will help with the water, but there is not much help in lifting the motor. When I used to put it on a trailer after each sail, it was easier, but I currently have a slip and it stays in the water throughout the summer.
The issue with the motor mount is the straw that broke the camel's back for me. I loaded the mount incrementally and 30 pounds is all it will help with. So I checked prices on a heavier mount and decided to just buy a lighter motor. I found a suzuki 2.5 hp 4 stroke (DF2.5L2) that weighs in at 29 pounds and ordered it. So when it gets here I'll have one more thing checked off my chore list. I didn't find a lot said about the model by folks sailing ComPac's but what I did find was positive, so I went that way.
I think you will be very happy with that decision!
following this thread from the beginning, I think that you reasoned yourself into a good decision. Now you just have to get her out on the water.
mike
Yep. Lotta stuff to do yet, but the list is getting shorter!
I had a 55 lbs Merc 6 hp on my 77 C16 with no issues. It was overkill, I couldn't use more than 1/3 throttle so I sold it and went to a Honda 2.5, weighed maybe 30 lbs. Much better balance.
The Suzuki 2.5 should be about perfect.
I have, and love, a Honda 2 HP long-shaft motor. I have never wished for more power and I really like the light weight
Please give us a review of your ne Suzuki when it arrives.
I have a 57lb ish Yamaha f4 on my 16 and it works perfectly fine
does sit back on the trim a bit, but really... when you have a few hundred pounds of people or more sitting back there, 60 lbs is the least of your worries for the trim level of the boat...