TOPIC: New member...1979 Thompson Sidewinder

Thanks, I saved that search! That's pretty interesting. I've never seen them before. Looks like the first one shows 226, second one 726, and the third 826.
I'm not really sure what the claimed speed should be, just rough guesstimating from what I've read at on of the powerboat forums. They were getting an easy 65mph with 150 egg beaters and most were running Super 18's. I'm sure the lighter weight engine helped. Some of the guys were getting 70+ on gps. So I don't think 50 is out of the question being a light hull that will be mostly out of the water. If I went with one of the 4.3 Mercs it could be 190-250hp. Now if it were Volvo, their ratings start at 240 and go to 280hp with the V-6. All depends on what I find for a reasonable parts boat. I like those variable pitch props though. Have you tried trimming down some to keep more bow down more on launch? That would make for a great holeshot!
I gotta watch that video again lol.

Just as a "for instance", there's a 79 sea ray local to me for sale. Junk hull but has a running and winterized 5.0 and Alpha1 drive....$300. No sense in even messing with the 470 that's in the Sidewinder for that price.

Every time I watch that vid towards the end where the guy is changing blades on the dock I get jumpy. If that was me the first thing I would do is drop the wrench in the drink, the second thing would be accidentally kicking the new blade in the water while standing up. How many screws, nuts, springs, etc. have I dropped in the driveway or garage where they disappear into oblivion never to be found until three months later when they just magically show up in plain sight.
Second boat I ever owned was the Johnson with the Buick V6. Bullet proof engine. Had the OMC 800 on the back. Still have a new fuel pump for that motor sitting on the shelf, never used.

We just like the rush of full trim to launch it like a rocket. When skiing or running against someone side by side, I start with very low trim and it will rocket forward and flat. It relies on a little trim to speed up the shifting... but it is tunable with different weighted return springs. All 3 of those props appear to be the 26 max pitch which was designed for the I/O. I agree with 63 Sabre... no wrenching where I can drop something. I just inspect mine on the workbench each fall to ensure I don’t have a broken cam or spring. When it is on the lower unit sitting on a trailer, you can just grab 2 blades and pull away from the hub as you twist and can see and feel it change pitch smoothly and quietly. I love my prop because I stopped changing props twice a day... low pitch ski prop for skiing during the day that I could not run fast without hitting the rev limiter, then big speed prop for evening speed runs before fishing started. I would struggle if one more adult wanted to ski after putting on the speed prop and also couldn’t race a jet ski with my ski prop. Now I can swap uses without swapping props. This will not be as good on top end as the perfect speed prop. However, on a shorter lake, it will take a little while for someone to catch up from your hole shot and mid range acceleration. Your boat is one of those that is fast enough to fall into the same propping dilemma.

Yep, saw that before on S+F. Only thing is don't run a surfacing prop with that, as will sling a blade to easy. Remember long ago a prop that you could dial in your desired pitch. My Dad had one, but it was for smaller motors. Hell, thats all the WAS 70 years ago OB's small HP compared the beast made now!

You are right on Robby321. Outboard people shouldn’t use high transom mountings or vertical manual or hydraulic jack plates as you don’t want the blades slinging out of the water as it puts great stress and imbalance by unloading and loading stress one blade at a time. A stock I/O outdrive should keep the prop under water, but if someone raises the x- dimension where the blade could surface out of the water, then this prop should be avoided. Thanks for adding that cautionary note Robby... I appreciate you keeping people safe (while we get a little wild).

I couldn't bring myself to doing any work near water either lol. I've lost way too many bolts or small parts in my driveway or yard. I don't have a garage so if anything falls it's usually gone unless I watched it drop. This year alone I lost 4 brightly gold colored hitch pins for my tractor...in fresh cut grass. Assembling rifles is another one. I smartened up and set up a trap out of cardboard when messing with springs. So far it's worked out well.
That Buick V-6 in the Johnson was good on gas too! Never gave me any problems. Always ran well and the only maintenance I ever had to do was oil changes. Great engine. Even the OMC drive that everyone calls the Leg Of Death never gave me any complaints. Maybe because it was well cared for before I even got it? Again, only maintenance from me was oil changes and water pump impeller changes. It served me well.
I tried to find that boat last year hoping to buy it back but came up empty. Did find another identical boat but it was missing tell tale hole I had on the gunnels where I had downriggers mounted. I suppose that find was for the best, it was in bad shape.


I'll keep that prop in mind for when we finish the Chieftain too. It's definitely not a performance boat but would certainly help getting her up on plane faster. We also wont be pulling any skiers either. Never got into that, we did do some tubing when I was younger but have since outgrew that. A friend and I used to try to fling each other off the tube at speed, got pretty reckless lol. I'll leave that stuff to the kids now.



I was looking at the transom a bit closer and figure I'll have to find something with the same length drive. There's really no room to move it up so not going to be an worries of surface driving a prop. As it is, if I find an Alpha the correct length, they have two extra studs up top. I'll have to build that part of the deck out to bolt those studs down. The deck angles towards the bow at that section. Easy to do, just another task to make it right.

If you would troll with the chieftain, you can achieve slower speeds if needed because I believe it starts at 11 inch pitch. It certainly help get a heavy boat moving. Sounds like you have everything figured out on the 16 footer. Now if someone will just show up with free motor and outdrive, help you put it in and also bring the beer, that would help the project along. Your past experience leads me to believe you have got this! Good luck!

Dr.Go! wrote: If you would troll with the chieftain, you can achieve slower speeds if needed because I believe it starts at 11 inch pitch. It certainly help get a heavy boat moving. Sounds like you have everything figured out on the 16 footer. Now if someone will just show up with free motor and outdrive, help you put it in and also bring the beer, that would help the project along. Your past experience leads me to believe you have got this! Good luck!

Hmmm...yeah, I never put that into though, that would help with trolling with the lower pitch. I don't have a dedicated trolling motor for the Chieftain. I planned on just idling the L6 along as slow as I could. Done it that way before with the Johnson, although it isn't ideal. Can still be too fast unless trolling against the wind. But it does work.
The Chieftain really isn't very heavy, aluminum hull. Not sure what it weighs but I do know it's lighter than a 21' glass boat. But, a 21' glass boat has a nicer ride in rough water with the extra weight.
I'm positive I can find a nice buy on a complete parts boat. There's so many of them around here. I sent someone a message last night that has 2 boats they want out of their yard. No reply yet though. Not in a rush yet either so no biggie. I'll most likely end up doing the swap myself but that doesn't bother me any. I've had the engine and drive out of the Chieftain already, then back in once the transom was rebuilt. Didn't take long at all. Only issue was being able to get the engine up high enough over the tall gunnels. This Sidewinder will be cake. I can put the boom on my tractor and snatch it right out.
I'm a hot rodder at heart and worked in garages most of my life so messing with engines is in my blood lol. I just don't like the newer stuff with all the computerized crap. I'd much rather sit down with a carb and distributor and do the tuning myself. Hell, I still have all the old meters for setting dwell, old school timing lights, and vacuum gauges. Not much else to use them with now.