rp35

[muscrat]

Hi

New member (been reading the board a while though- great resource) and saw a 35 rp that is relatively local to me in virginia. I sold my albin 28 last year and want to move up. The rp has a 265 perkins in it which cruises at about 14K (from my understanding) and i need some more speed out of it. The current setup is a 2.0 gear, 1.75 shaft and a 28" prop. A couple questions for the board that may be familiar with the hull- is a cummins 370 enough to cruise this boat at 18K? If not, based on some reading it sounds like 425-450 may do it, My preference is a cummins, QSB maybe?? - which is a 3400 rpm motor- if this is the case, is a 1.75 shaft adequate? I understand that it wasnt meant to be a +20K hull and I can live with that, I'll keep the boat light, just want to be able run faster when I need it.. Thanks for any help!

Steve

 

[MASTERENEGADE]

I know theres a few guys on here who own and have owned 35rp's. Im sure they will chime in shortly.
From what I know of my JC which is a smaller 35'DE, if i were to try to get a 18knt cruise I need atleast 400hp if not closer to 450, so Im assuming the same for the 35RP.

 

[lobstercatcher]

Did you already buy the boat?

The shaft is probably just enough for the hp you may need to get. But if the boat was being built, I'm sure the finisher would put in at least 2". The rpm really doesn't have that much to do with shaft size. The boat might already be past the keeping it light stage so 370 might be getting to the lower end of where you really want to be. IOf you go bigger It probably would be a good idea to upgrade the shaft etc.

 

[Frank Grimes]

Tunamojo had one with a C9 @500hp, I think she cruised at 18 topped 22. I'm sure he'll be along to confirm or refute those numbers.

 

[tunamojo]

Tunamojo had one with a C9 @500hp, I think she cruised at 18 topped 22. I'm sure he'll be along to confirm or refute those numbers.

Yes in fact when she was mine… she would do more like 20 cruise 23 WOT

when I sold her, her new owner added a lot of weight and was seeing 18-20

 

[DBM]

Ive got the RP 31 with the QSB 380 in her and she tops out at 20 knots, so my guess is to get the 35 to those speeds you'd be looking at 450 hp at the least.

good luck.

DBM

 

[hntrss]

Just my opinion, I owned one too. If you need a true 18 all the time I would look for another boat. You will have to reshaft, repower and burn a ton of fuel to get 4 knots. They just aren't meant for speed. I had a heavy boat, but with a 430 cummins, 2:1 gear you were looking at 15-16 knots at cruise. It only went 19 wide open. On the other hand 14 knots with 260 hp is probably a comfortable and economical ride.

 

[muscrat]

really appreciate the replys. No, I havent bought the boat yet, looking at it and wanted to understand what I was in for before I moved forward, versus looking for something already done and know for sure it does what I want. Real world numbers/ exprience definately help and Im a noob on this stuff- so again appreciate the comebacks

Steve

 

[Tuna Pursuit]

If you love the boat and everything else is good don't worry about the 14k cruise, you'll be old like me someday and only want to do 12:grin:

 

[lobstercatcher]

If you love the boat and everything else is good don't worry about the 14k cruise, you'll be old like me someday and only want to do 12:grin:

The boat is cheap enough. I'm surprised nobody bought it a long time ago.

 

[tunamojo]

I forgot to mention, the RP 35 was not designed for speed and handles anything out there , well, at 12-16 knots

 

[muscrat]

@ hntrss- thats one of the power combinations I was headed, so that gives me an idea what I could expect.

the 14K is a challenge/concern, I have a pretty good run to the ocean so i need to balance that with the ability to do that speed as opposed to slowing down in other style hulls in weather.
we do alot of slow trolling and drifting, and ive read here on the site this hull sits well so thats a big plus.

Thanks again for the info, gives me some things to consider.

 

[jnoon]

Don't be surprised if that boat has a more realistic cruise speed of 12kts.

 

[Powderpro]

1.75" shaft is small for a 28" prop. If you want to upgrade to 450hp - 500hp to get the cruise you want, then I would make plans to increase to a 2" shaft. I would go with more displacement than a QSB in a boat as big as the RP. The QSC, or a 9 liter from Iveco, Deere, Volvo, Cat would offer a much better cruise than a QSB.

 

[hntrss]

@ hntrss- thats one of the power combinations I was headed, so that gives me an idea what I could expect.

the 14K is a challenge/concern, I have a pretty good run to the ocean so i need to balance that with the ability to do that speed as opposed to slowing down in other style hulls in weather.
we do alot of slow trolling and drifting, and ive read here on the site this hull sits well so thats a big plus.

Thanks again for the info, gives me some things to consider.

Don't get me wrong, its an awesome boat--at 15 knots. I lived on it and commercial fished offshore everyday of the Bluefin season for 10 years. It is so comfortable to be on that 15 knots actually starts to seem pretty fast. Or maybe I'm getting old. I always told everyone to break out your calculator and figure out the time to the grounds at 15 vs 18 knots. You may be surprised how little time you are saving. For instance on a 50 mile run it takes 2 hours and 45 min at 18, and 3 hours and 15 minutes at 15. Sometimes I waste 30 minutes on the crapper in the morning..........Just saying. You can save a lot of fuel if you add up those 30 minutes every day!

 

[hntrss]

1.75" shaft is small for a 28" prop. If you want to upgrade to 450hp - 500hp to get the cruise you want, then I would make plans to increase to a 2" shaft. I would go with more displacement than a QSB in a boat as big as the RP. The QSC, or a 9 liter from Iveco, Deere, Volvo, Cat would offer a much better cruise than a QSB.

Something is wrong with those numbers, unless it is a very low turning engine. No way you are spinning a 28 inch wheel with 2;1 and 265 hp

 

[Powderpro]

Something is wrong with those numbers, unless it is a very low turning engine. No way you are spinning a 28 inch wheel with 2;1 and 265 hp

It will turn it fine, but the prop won't have much pitch,
probably in the 18" range. 30 minutes on the toilet in the morning? Wow .

 

[hntrss]

Shit happens.

 

[sailor of fortune]

That boat was discussed in another thread on here. The through hulls had Home depot type gate valves instead of real seacocks.
The long house set up, was geared toward cruising than fishing.

Personally, I liked the boat. I don't fish, so it would work for me. The through hulls would be changed, as would the electrical panels and some of the ghetto wood work.
If you couldn't live with the perkins power, I would look at other boats. The Perkins certainly would not be my choice, but if it was well maintained-I'd live with it.

 

[jwalka51]

And it takes 30 minutes to happen.