12' Olympian To Fill Some Voids

Discussion in 'Watercraft' started by LCnSac, Mar 17, 2012.

  1. We'll find out when the rain lets up. The Doelfin is on and ready, but that galv prop guard will be used for the low rivers. I am using the crappy weather as time to do some mods and maintenance. Fabbed a bow stop for the trailer which never had one--why? The boat is stripped of flyline grabbers, down riggers, and graphics. No one ever installed rear deck cleats (why?) so those are done, slightly below the gunnels. A few holes above the waterline filled, and the cad plated screws (???) for the transom motor plate replaced with stainless. Good opportunity to poke around in the transom and it's dry and rock solid. 5200 is my friend--as is acetone to clean up my occasional whoops.

    If non-ethanol gas is available in California, I don't know about it. Our standard blend is 5.8%E so for a small motor I'm not going to worry about it.
  2. Looks like there's a couple but not many. http://pure-gas.org/index.jsp?stateprov=CA The nice thing about getting non ethanol for a small motor is you can fill up a couple of 5 gallon jugs and be good for the season if the nearest station is far away. In FL I make sure I've got 8 jugs filled anyway before hurricane season because gas can be out for a week or more after one of those and then just use it up in the boat over the winter..

    Did you put in pop cleats at the back or just regular fly line grabbers? :)
  3. I am finding this discussion to be of interest. don't mean to hijack this thread, but mbowers' mention of the position of the cavitation plate in relation to the bottom of the hull, and that it affects performance, perked up my ears.
    My 16'er is underpowered with the 9.9 Bigfoot, and I can live with that for now. I notice that the cavitation plate on my 9.9 lines up a good inch or so lower than the bottom of my stern. That is why I was thinking of a jack plate. My stern has a fairly steep angle to it, so I don't really need the setback. What I think I need, is to just raise my transom about an inch (or maybe 1.5"), and then get something like a Doelfin.
    None of my local friends, or anyone I know, confess to being experts on the proper positioning of an outboard motor or tweaking the mount for performance, so, I figured that the manufacturers might have their stuff together and everything should fit just right, "out of the box" (Ha!), and just clamped the motor to the transom, drilled a couple of holes, and bolted it on. I also have a lock over the clamps, to help keep the motor from falling off when the boat's on the trailer and I'm not watching it.
    I'm rethinking this whole arrangement and wondering if I can get better performance by tweaking it a bit. I just don't know what I'm doing or where to start.

    I'm lucky to have a nearby gas station that sells non-ethanol gas. I won't run ethanol gas in any of my small gas engines.
  4. What you do, Jim, before spending any money on jack plates which probably won't do much for a 9.9 anyway is get some aluminum shims at Depot and start applying shims between the motor and transom. Using a GPS if you have one, do some speed trials including pitch. You will probably find a sweet spot pretty close to where you are now. A Doelfin will probably help too.
  5. Thanks for the advice, LCnSac. Messing around with shims and testing...OK, I'm good with attempting that. Once I figure it out, I won't have to wonder.
    I found a nice piece of Spruce that is the exact same thickness as my transom. I can sandwich that between two aluminum plates as a bolt-on extension, once I determine whether or not I have to raise the height. I have 3 pitch settings, and the middle one seems to work best right now.
    I have a new sonar/gps unit that I haven't even tried out yet, so I finally will be able to determine speed.

    My plan is to remove my thru-transom bolts, and then head to a lake and test it, adding shims to raise the motor's height until the performance peaks. Then check the pitch again. Sounds easy enough, anyway, as long as I don't drop my wrench in the lake.
  6. You can actually use what you have permanently Jim. Maybe epoxy the spruce but it's a light setup and you don't need to do much more than use shims. You can also play with prop pitch but for a small motor it's probably not worth the expense and effort. i have a stainless 3 blade on mine, as a result of the aluminum prop being chewed up. That's exactly why I don't like stainless props--it's a helluva lot cheaper to replace a prop than a drive shaft (I speak from experience on the Whaler) and I will probably get a new aluminum prop and sell the stainless.
  7. Thanks again for the advice, LCnSac. My 4 blade aluminum prop is in great shape. Only once did I slightly polish the leading edges of the blades in the mud by not paying attention, when going over the shallow mudflats. Was only the 2nd time I had it back in that shallow estuary (usually just paddle my yak back in there), and I strayed a bit from the main river channel. I quickly corrected and steered away from the shallows. Was lucky not to hit any woody debris. I now pay better attention.
  8. One of the key pieces of info to get the correct size prop involves using a tach to get the motor RPM. Using the GPS speed is probably good enough though. Adjusting transom height with shims etc is a great idea to get a feel for what's optimal. I wouldn't be surprised if it's 2-4" though. I was instructed to start with pitch / trim at the lowest hole and keep raising the transom until you lose performance. I still feel the jackplate is a much more secure way to increase the height of the motor than anything you bolt on the top of the existing transom. The setback should let you raise the motor even further as the water height behind the boat rises with distance back from the transom. The jack plate is only $85 for a solid piece of cast aluminum that's manually adjustable to the 1/2". It will be tough to rig something up that's not adjustable, half as strong and twice the price IMHO.

    I want to try a mini jacker out on another small boat this summer and I'm so sure you'll like it on your boat Jim that if you buy one for your boat and don't like it before I'm going to buy a new one (say mid June), sell it to me and I'll pay the full $85 plus sales tax and $10 for shipping (it's probably $20 for shipping from WA to FL) so your only risk (besides your time and a couple holes in the transom :) )is driving to the store and $10 for shipping.
  9. Thanks for the additional advice and offer, mbowers. I'm hoping to get the boat in the water sometime this Spring, and get it worked out. I just finished some modifications on my yaks, and I need to go paddle.
    Don't wait for me to get a jackplate, whatever you do. Just order one!
    Although I usually paddle my U-12 when I fish lakes alone, I might start taking the tinny.
  10. I wonder how much improvement you will get with a lot of tweaking. The Bigfoot is designed to provide a lot of low-end torque as a kicker for big boats. It's not really intended to be the fastest motor in its class. Raising it up to reduce lower-unit drag will help some as will a prop change, but if you can plane your 16, that is probably about all you can realistically hope for, IMO. As I recall, it's gearing that is your root problem--although the big prop isn't helping.
  11. Agreed. Same with mine; a 4S 15 hp on a 12' skiff. It's a 15 hp motor. How much performance can one expect, beyond planing and a little cruising speed. Back in the days we used to polish ports and re-jet carbs on the old 2 strokes, but we were just playing with small motors. The result was usually a little more speed and even harder starting and rougher idle. It's good to tune any motor and position and props but expectations should remain fairly low for the little guys.

    A Doelfin cures a lot of ills on a smaller outboard. I didn't have the need for one on my 90 Merc in the Whaler, but I've had one for every lesser powered boat and they really help with the pitch and hole shot.
  12. Thanks again for the additional discussion. I will keep all this stuff in mind. I wasn't aware that the Bigfoot was geared lower. I think the gears and lower unit are about 30% bigger than standard. I had heard that they were designed to perform better than a standard motor in the weird turbulence coming off the stern of those pontoon boats that resemble floating lounges. I bought it on the spur of the moment without doing much research, because it was offered at a significant discount, I was looking for a deal, and the boat that I have it on is an old ugly barge of a craft.
    My Bigfoot is a '05 that sat in a warehouse for 3 years. The dealer was clearing them out of his inventory at 20% below retail back in the Fall of '08, so I grabbed one. The motor runs smooth as silk at slow trolling speeds. (They now list new for $900 more than the price I paid for my '05).

    I might not get to working on this for a couple of months, as I am always too busy in the Spring (next Spring I will be retired, and will be too busy fishing, etc to do anything that resembles work!!!) and would rather just go fishing and paddling when I can get away, rather than messing around with different configurations of a mechanical mystery and attempting to improve performance.
  13. I think they are generally built for pontoon boats. They are a low end torque motor, and have a little more drag than the other models. You got a good buy and you have a good motor. I think you can tweak it a little but I don't think either of us will be in the speed trials anytime soon.

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