My engine weight vs another higher HP engine weight

[randyray41]

I have a 78 70 hp evinrude. I would like some more HP but cant put any more weight on back of boat. Is there another say 85-90 hp motor available that would be a comparable weight to my motor?

 

[jimmbo]

Why can't you put more weight on the back? If the transom is weak, more hp will do it in too. If the boat is too heavy in stern, some weight needs to be moved forward. Just out of curiosity, what is the boat rated for HP wise?

 

[randyray41]

I have no idea what the hp rating is on boat The shifter is blocking the plate for rated HP. . Nothing wrong with transom. I did move battery to front of boat. The problem is keeping stern above water. My thumb nail is pic of boat. As you can see its low in water with the 70

The boat is a 13' 1987 rapid craft.

 

[jimmbo]

70 hp on a 13 ft boat sounds a little much as it is. You could remove the remote control to view the hp rating

You've.posted on a few other boards about this boat. Did you get any info as to hp rating from them?

 

[randyray41]

No, I haven't been able to find any info on boat. I can't even find another boat like it. I have searched everywhere.

I think I will take shifter off this weekend and see what it says on plate if its even visable.

 

[Scott Danforth]

you may only be rated for 40 hp http://boatspecs.iboats.com/Rapid_Craft_by_Phyber_Dynamics__13V__1995/bp/66b70267

 

[randyray41]

The company who made the boat was called Rapid Craft. They went out of business, from what I heard because of a lawsuit over selling a very high performance boat and not giving the purchaser any training to operate the boat which resulted in a death.

I don't know what Rapid Craft called my particular boat.

The boat handles the 70 hp with no issues. Its just a weight issue. I installed a 9 gal fuel tank which is in the rear. The orig. setup was the tank in front and battery in rear. I moved battery to front because I don't have a fuel tank that I can install to add fuel through front of boat safely. The weights of each should be close to same. Fuel probably 10-15 heavier than battery.

 

[Scott Danforth]

Has nothing to do with weight issue. It has to do with the boat wetted length, boat transom width and boat transom height

33 CFR SS 183.51 to 183.53

That is what determines the rated HP of the boat based on international law. Its what the USCG uses to spot check, also what the manufacturer uses to set rating

Again, you may want to check, pretty sure your rated for less hp

Rapid craft name went out of business at least 3 times with 2 different manufacturers

9 gallons of fuel is 54# plus the tank. A small marine battery is 32# plus the hold down