What Size Engine?

[jasonbailey]

I have a 18.5 foot Rivieria Tri-Hull boat built in 1984. Currently it has a 75hp Chrysler hanging off of the transom. I'm kicking around repowering the boat and was wondering what size engine I should get. The plate that states the boats max engine size is long gone. And the company that made my boat, Rivieria out of Florida looks to be out of business. I was considering bumping up to 90hp or better. What do you guys think?

 

[LubeDude]

Re: What Size Engine?

Heavy boat, I would go 115-140HP if it all seems solid. 90-140 is generally the same weight depending on the manufacture, Im always for powering a boat to the max recomended HP. I would think an 18' boat should handle a 140. Just because ya have it dosnt mean you have to use it, but it is nice to have when ya have to head home if the weather turns bad. You will get better economy with a larger engine usually because you do not have to run it as near to WOT for a decent cruise speed.

 

[JasonJ]

Re: What Size Engine?

I'd go big as well. My 16.5 foot tri-hull is rated for 145 hp, its a safe bet you could probably go to 175 and be fine. Tri-hulls need more power than a V-hull of the same length, and they are generally rated for more power because of that (and the fact that they are more stable and usually stronger than a v-hull). A 150 would probably be just fine. I have secret hopes of finding a 150 at a good price laying around, my rig would benefit from more juice.

 

[ZmOz]

Re: What Size Engine?

I would try and look up what the max rating is (it's got to be on the internet somewhere) and then get that much or slightly more.

 

[LubeDude]

Re: What Size Engine?

I was trying to error on the conservative side, but if it will hold a 150, then by all means do it.

 

[walleyehed]

Re: What Size Engine?

Depending on the beam of your boat, I think LD's advice of around 135-140 would be close.<br />Jason, what make of tri-hull do you have???<br />My dad's Glastron 17'6" is rated for 140 max...<br />My 18 is rated for 150 max...kinda skipped that though...... by about 75