Yamaha 784cc into welded mod-v hull

86tuning
Posts: 106
Joined: 11 Oct 2017, 01:49
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Location: BC Canada

Yamaha 784cc into welded mod-v hull

Post by 86tuning »

Noob here, in the dreaming/preliminary stages of building a shallow river runner to access fly spots in southwestern BC. I've been lurking for a while, and searching hasn't found me any answers.

Thanks to all the guys with jet-jon build threads, they're informative and very inspiring!

Currently, I'm running a 1969 Starcraft Offshore, which at 18ft and 2ft draft (with o/b and prop) is a bit big for the rivers I want to get to. The big tinny is nice for bigger waters, trolling in the saltchuck and other stuff. Hidden gravel bars under murky water, and small streams aren't that fun. My aluminum props have had hard lives.

The dream: 15ft aluminum bass/crappie boat with small center console, large front and rear fly casting decks, and a fraser river anchor. Mod-v hull with some V for less pounding in rougher waters.

Question #1.
What are the dimensions of a Yamaha engine and pump assy? height and length, and maybe weight and width. Yammy motor and pump because of the aluminum inlet. Haven't purchased the waverunner yet, still looking for the right deal on a recent model. Want a functional reverse bucket, modern gauge, etc. Hoping to have the engine under a flat rear casting deck. How tall are they?
edit: picked up a 2000 waverunner so can make my own measurements. will post results when donor is dismantled.
edit2:20181208 engine is 22" tall, 22" wide 19" long, about 120lbs without muffler components.

Question #2.
What size/shape delta pad do I have to make for the tinny hull I haven't yet found? Tracker Grizzly mvx1648 are locally available. Yes, a bunch of cutting and welding, but I have a buddy that does sheet metal fab and TIG welding. Of course, once I buy the waverunner, I'd have a pattern to go by, but at this point, I'm still in the planning stage.
edit: donor waverunner has no delta plate. modern ones have a small 6" wide ride plate behind the jet inlet.

Question #3.
Build my own hull? Won't be cheaper than the Tracker 1648 MV at CAD$4500/US$3200 but at 580lbs and 7deg constant deadrise, I may be able to do lighter and have a proper mod-v with deeper deadrise at the bow for better wave entry. An 8'x20' sheet of 1/8" 5083 is about C$1400/us$1100 plus I'd have to buy my own TIG welder for a project this big, and deal with a fab shop with a large press brake to do the major structural bending.

I've been mulling over this for a while, and have started building a couple paper models in 1/12 scale to visualize the boat better. But now need dimensions. Not very many used waverunners available up here in the Great White North (tm) at reasonable prices.

See you on the water,

Brian
Last edited by 86tuning on 08 Dec 2018, 18:15, edited 3 times in total.

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