BMW K1200GT Powered Jet Boat?

Since I have stopped using twitter and the account has been hacked, people have been asking what I have been working on since retirement.

The truth is mostly (boring) home projects that I have put off to list our Redmond house for sale like clearing out a creek bed, removing tree stumps from our yard, tearing down and taking an old barn to the dump, clearing out land around our Florida house for a new fence and gates. The plan is to sell the Redmond House and “snow bird” between a pacific northwest house on the Olympic Peninsula and our house near Key West.

A couple of these projects have been “interesting” like refurbishing* a 1985 460 big block 4 speed, F350 and using it to tow a 10,000 lbs/32′ boat to Florida and even fun projects like buying a 2002 (Red) Turbo beetle for my daughter and restoring/resto modding it back to as new condition. (This picture I am polishing the headlights back to a clear state)



All that said one project I have been looking forward to the most is attempting to install a Super Bike engine into an older jet powered ski boat to make the “ultimate” shallow water flats boat for Florida.

My goals for this project are:

  1. Quiet at idle
  2. Shallow running
  3. Capable of ~35 MPH
  4. Light weight ( so it runs shallow and I can lift it with boat lift) .
  5. Doesn’t burn a ton of fuel
  6. Large enough to take my wife and daughter snorkeling



To this end I have been watching the Insurance salvage sites, OfferUp and Craigslist for my “donors” vehicles.

The first vehicle to show up was a 2006 K1200GT BMW that had been in a fire. I bid $25 and much to my wife’s chagrin won it!

After tearing off the melted fairings, burnt seat, destroyed fenders, replacing the wiring harness and getting new handle bars (To replace the burnt switches). I managed to get it started and have a very light 150HP, shaft drive, four stroke motor for my jet boat project!!!!!!! Woot!


Now to start looking for a donor boat that met my criteria: An older fiberglass ski boat, Jet Powered by a Berkeley pump (most common jet to ease finding parts), on a trailer and the most important part the cost needed to be near free!

The last boat I found that fit this criteria was an 18′ Apollo for $500 listed 5 years ago….With the boat shortages due to the pandemic I assumed I would be looking for at least 6months.

The plan was while looking for a donor boat I would turn the bike into a Café racer/scrambler and ride it in the neighborhood. (my neighbors would love that!).


Found a donor boat!

While scanning the local craigslist I found an for: “$300 Ski boat”. No manufacture, no age, no engine details but in looking at the pictures I can see it has a solid looking trailer and a Berkeley Jet.

So like any wise shopper I told my wife I was going to “Go shopping” hit the ATM for $300 and told the owner I wanted it -sight unseen! (Okay not that big of risk as the trailer was worth more than the asking price).

So what did I get?

While there was no identification on the hull; from pictures, I identified it as a ~1972 17-foot Jolly Rogers 17.

The Berkely Jet is a 12JC-A

When I lifted the engine cover I was shocked to find an engine!….Specifically an Oldsmobile Big Block 455, per the casting marks with factory forged internals and Hardin Manifolds!!!

Unfortunately, a previous owner had pulled the intake and distributor allowing the engine to fill with water (grrrr).

So what’s next?

Clearly I need to remove the current motor and mount the motorcycle motor into the boat….which will be interesting with the bmw motor designed to be suspended from above versus supported from below like the Olds 455.

That said I see some other issues right off:

  1. The hull is much deeper V than I was hoping and likely will run deeper than wanted….But will want to put the boat in the water with the new motor to see if this needs “fixed” (Remember boat is going to be losing a bunch of weight in the conversion)
  2. The Berkeley type “A” pitch impeller is designed for a big block Oldsmobile with ~225HP, ~400 ft/lbs Torque @4000RPM versus the BMW with ~150hp and ~100 ft/lbs Torque @8000rpm. The correct solution seems to get a different pitch impeller like an “E” impeller…..but since the bike has a 6 speed transmission wondering if I can just run it in 1st. (With the Olds 455 it was likely a 45MPH boat….I only want 35MPH)
  3. While the boat bottom seems solid, the transom looks rotten (to be expected for a $300 boat<sad smile>


As I will be fishing in Florida much of the Spring and Fall guessing the first water trial will be next winter.

(Yes I realize I am snow birding a little off….This schedule to spend the Holidays with the family in the Pacific Northwest)





*Pulled the Ford F350 460 big block and replaced clutch, intake manifold, Windshield, carb, fuel pump, water pump, alternator, pressure plate, valve covers, brakes, alternator, wiper motors, all the belts, new seats, navigation, master brake cylinder, heater fan, power steering pump, new gauges, rebuilt the dash…..In Retrospect not certain I would have towed such a large boat across the country in such an old truck…..but very very glad it is done!!!!

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