20 HP Mercury and 20 HP Tohatsu Racing Propeller

[Mini Max]

The c/l of the prop shaft 3/4" below the bottom is the same as the UIM GT-15 and GT-30 classes and the APBA stock runabout classes. The Tohatsu has a electronic guardian mode for overheating and no need for modifying the engine for low water pickup has become evident. There are many "tricks" we use to get water to a stock engine that are non invasive but why? The engine cools without messing with it so far.

By buddy Harry Schoell is also building me a prototype prop. He is 80 and we are working to get him to the Top of Michigan Marathon 2024. Before Todd Anderson provided me my first props from LAK, Harry designed a prop for the four stroke 20 that he is building in his garage. Props and boats. Boats and props. My DSR came from a sketch he made of his CSR he built in the 60's.

[dandrews75]

Ok, so no cooling issues so nothing to do there. If you are going to run that boat you need to add a pad to the bottom. I would say 1” thick by 8” wide and 2’ long blended into the boat. It might not handle well with this. Other option is to add steps. You have to much drag at this point. Really need a Dillon boat or a smaller version of a delta, critch or voodo. In fact, I saw an 11’ delta on kijiji in the summer, they are really uncommon. A Zorkan might work also. I think this is a boat issue at this point, need something to handle the high c of g and be able to set the balance. My dad had a 1973 14’ Springbok with a 1985 Mariner 25 hp that would do 42 mph with just me in it. That whole outfit weighed 292 lbs. The GT 30 kilo record is almost 60. So there is a lot on the table with these 4 stroke engines. Might want to check with the TBoat guys on the High Performance Boating Canada website.

[Mini Max]

APBA stock outboard has a very few boat rules but one is no more than a 5/8" longitudinal step in the hull bottom and no transverse step. Tim Kurcz bought me the Dillon plans and these photos are of his Ropp/Kurcz design DSR "Summer Daze" a high point champion. His pad has the outside edges beveled. This makes the boat track better and gets the thickness to within the rules.

My friends had a rule when bar crawling which was "go ugly early" then the pressure was off to find someone better to take home that night. I never bar crawled but I have had a lot of boats and I suppose "go ugly early" got me boat riding first, and now the pressure is off to find something better.

[dandrews75]

You were reading my mind, I was coming back to comment about Tim’s boat. I think an 11-12 foot version of this boat would be the ticket. I also believe we may need to get away from the current rules governing utility boats. I can see class realignment including or resembling GT15/30, T750 and T850. The TBoat classes are raced in Ontario and I really think they should be included in stock outboard. Will be interesting to see what HRL has up their sleeve. They attempted a takeover of CBF at the November AGM. Wondering if an outboard series is in our future. NBRA has made the engine legal for hydro classes. So change is coming. I think we are pretty well at the wall with the current boats being tried. Like anything once more people get involved advances will come quickly. Too bad Ed Karelsen wasn’t here still, I’m sure he would’ve sketched something up.