RF18 - Repower - 115 PRO XS

[snelly]

My old Yammy F115 has died - no regrets she always got me home and never let me down - 17 years and 1750 hours is a fair innings.

Have decided to repower with the new 4 stroke Merc 115 PRO XS.

 

The question is which gear box.......

 

I'm after some real world numbers and experiences with both so I can decide but I'm biased toward the standard gearbox despite the dealer trying to direct me to comand thrust.

 

Thanks in advance

 

Snelly

 

 

 

[geeviam]

I don't have real world experience, but this forum member does: http://mbgforum.com/profile/12240-davec29/

He's got one with the CT gearcase, on his Maverick Master Angler 17, and he likes it.  If I was looking to repower an RF 18, or other boat in that weight class, with a 115 HP, I would go with the Command Thrust model, for load carrying, better hole shot, and many more props to choose from (i.e. Tempest Plus, Trophy Plus, Enertia...).  Just my opinion though.

[snelly]

The new motor is on and it's a bit like when I first got my  RF18 10 years ago the more I use it the more I love it. Have tried a few different props and down to some fine tuning now. Have seen 43 kn/50mph but most a running a touch over 40kn and the motor has to loosen up a tad yet. Have put 28 hours on it in a couple of weeks.

 

Best 2 props so far a 20p Laser 3 Blade and a 19P 4 blade Trophy

 

More to come but very impressed.

 

Cheers Snelly

[geeviam]

Congrats Snelly!  From the numbers and props you mentioned, it looks like you went with the Command Thrust gearcase.  Is that correct?

[snelly]

No mate - Standard gearcase. I went with the idea that the big gear box was not needed and with the standard you have less drag and better draft.

 

Cheers Snelly

 

[snelly]

40 odd hours down on the new motor and loving it.

So far have run

22 Laser 3 blade - Too much for this set up but ran 38kn

19 3 blade  K series Yamaha - saw 43kn but over revved only a short run as I didnt have the prop nut locked - yam cotter pin v merc lock washer

19 Spit fire 4 blade ran 41kn against the tide in the river and 43 Kn with the current but was only seeing a tad over 40kn offshore with 3 pob

20 Laser 3 blade ran 41 kn thought I would have got a bit more but was able to get to 6,100RPM which was the best result so far

19 Trophy 4 blade ran very nice and had more bow lift going to run this a bit longer to get some more data.

17 Power tech RXB ran to 6,200rpm and 40 odd Knts an 18 would be perfect.

 

Going to stick with the 20 Laser as my main prop and keep the 19P trophy as it has good grip and boat runs well with this one.

Will try another run with the 19P 3 blade Yamaha K series now I have fabricated a washer for the Merc lock nut.

I suspect that the 3 blade best prop would be in between 19 & 20 but where do you stop ? 

 

Great motor and super impressed with it.