New 2 boat setups

[Limelight]

Total noob here when it comes to optimizing a checkmate for speed. Hopefully y’all can school me on which direction I need to head. I have fast drag cars under my belt, but boats are new to me. Last year I picked up my first “speedboat”, a hideous 1979 exciter powered by 220 XRI laser turning a 23p laser prop( no set back/transom mounted)After having the motor rebuilt, I took it out but could only hit 55-58mph @ 5800ish rpm. Maybe I could be wrong but I’m almost positive I should be going faster. I was planning on doing a jack plate with a 6” setback but what else can I do or am I missing to get this thing running like a raped ape?

 

[karzrus]

The Jackplate is the answer, but you need to have a solid transom and hopefully a water free hull. Old boats collect water if the fiberglass has been compromised, the transom, the wood stringers, plywood floor, floatation foam and balsa core material will all pick up water(add weight) and weaken the structure.

Is the floor soft? Does the transom flex? Was any of it replaced?

If the hull is dry (rare in an unlooked after 40yr old Checkmate) Set up the Motor on the Jackplate so at the top of the travel the propshaft centerline is even with or an 1" or so above the bottom of the hull. To run the motor this high you need a low water pick up. IIRC Exciters are 19 foot hulls, so they like more setback than just 6" for best speed. Think 10-14" but again you need a solid transom. The other thing to consider is quality steering components. Old style single or dual cable set ups are not the best for speeds above 60mph and worn out set ups...well.

Hope this helps, there is more information available, but how much do you want to spend?

 

[Limelight]

Thanks for the reply! The boat has had a new floor put in about 3 years ago and I did not feel any soft spots. I did the hammer test on the transom and could only find one small “dead” area but it doesn’t appear to flex any. I will be taking to boat to a guy who rebuilds old style fiberglass boats for his thoughts on the hulls condition. I guess I would be willing to spend enough if it made sense, otherwise I would start looking for a better hull.