Manual Jack Plate level information for a Stratos Vt Rocket 200 Yamaha

[Jono69]

Good evening. I have recently purchased a 1987 Stratos VT Rocket 200 with a same year Yamaha 200HP outboard, 21 Pitch prop, and a manual Hi Jacker jack plate. This boat has a tunnel hull. This is my first personally owned outboard rig but I have been around and used them over the years. This is however my first adjustable jack plate. I prefer cruising with this rig around 3-3500rpm which typically results in a 35-40 mph speed. This speed seems to be a fairly comfortable, economical setting and keeps the boss from whining too much. My issue is that I have to have the motor buried all the way down (IN) with the trim to keep the bow from bouncing up and down excessively at and around that speed, in smooth water. If I begin to accelerate from there and really start getting it, it does smooth out and I can trim up a bit. I think thats where the tunnel hull starts to do it's thing. Can adjusting the jack plate up or down help smooth out my bow bounce at lower speeds? I'd imagine I am losing a lot of performance with the motor trimmed all the way down (IN). Also, I do not have the option of trim tabs on this transom.
Any help or suggestions would be greatly appreciated!!
Thanks,
Jon

 

[Frank Acampora]

Re: Manual Jack Plate level information for a Stratos Vt Rocket 200 Yamaha



I guess tunnel hulls have a spot where nothing seems to ride right. This small tunnel does exactly the same thing until it passes critical speed. As soon as it breaks over onto plane it starts bouncing and porpoising until speed gets up over 30. I first raised the transom 2 inches then later raised it to 5 inches. The boat always did the same, even with the engine at different depths so I don't think raising or lowering your jackplate might help.

You might go over to the prop forum and inquire about stern lifting props for your engine. That type prop might help some.

That's all I have.

 

[metriccrescentwrench]

Re: Manual Jack Plate level information for a Stratos Vt Rocket 200 Yamaha

It's my understanding of tunnel hulls that this is kinda' the nature of the beast, you get a certain speed range where they're starting to provide lift but it's not quite enough. You might ask the same question in the setup forum at screamandfly, they have lots of go-fast boaters who hang out there.

 

[Jono69]

Re: Manual Jack Plate level information for a Stratos Vt Rocket 200 Yamaha

Thanks guys. Much appreciated. I think I am going to look into getting a stern lift prop. I was planning on getting another prop anyways, so this works out. I think that might help a little bit, in theory anyway. Any recommendations for those?