53c numbers

[Mike36c]

The Admiral and I have decided to move up to a larger boat and it looks like an older three stateroom model 53c might be in our future. I spoke with an owner yesterday about his boat which is for sale, it's equipped with 12v71n's and he claims a 20mph cruise @ 40gph and a top end of 25mph. Why he used mph and not kts seemed unusual and the speeds seemed way optimistic. Can you nice folks here post some real world numbers (hull speed, cruise, and max) for a fully loaded 53c with 12v71n's and 12v71ti's? And can the n's be run at WOT as long as they turn rated RPM? Thx

 

[bigbill]

mike i have a buddy that has a 53c with 12v71n engines, his wot is 18knots cruises at 16 i think. maybe david will chime in when he reads the thread

 

[Boatsb]

I'm not sure what hp the 12v71ns are but I know captain mike pulled them out b of his and put in qsm11s. He's probably getting the 20/25 with the qsm11s. I believe it was less than 20 wot before.

 

[jim rosenthal]

Tom Slane had a 53C which they repowered with M11s, rated at 700 hp I think. She did 28 kts on sea trials and would cruise 24 kts. The power is about the same, but the weight difference is considerable.

 

[Boatsb]

Tom Slane had a 53C which they repowered with M11s, rated at 700 hp I think. She did 28 kts on sea trials and would cruise 24 kts. The power is about the same, but the weight difference is considerable.

Jim I don't think 1271ns are 700 hp. If memory serves 450 or so.

 

[nor'easter]

The N boats I have looked at (53C) have been 525 or 550 hp. The TI boats in the 650-750 hp range if I remember right. I think the N boats are ok to run on the pins at 2100 rpm. RSMITH has Ns in his 50C and will likely comment.

 

[saltshaker]

Years ago I looked at a 53C with 12V71Ns. Owner spent some money trying to maker her faster. I remember her cruising around 17.5kts and wot around 20kts. 525HP at 2300rpm and you can cruise at 2100-2150 all day long. Big iron for that HP

 

[Boatsb]

The er is a dream with qsm11s. Also about a ton per engine lighter.

 

[rsmith]

Years ago I looked at a 53C with 12V71Ns. Owner spent some money trying to maker her faster. I remember her cruising around 17.5kts and wot around 20kts. 525HP at 2300rpm and you can cruise at 2100-2150 all day long. Big iron for that HP

That's the #s. Lifting rails and one piece shafts will get you another 2kts with no HP increase. Even the 650HP TI boats won't get much more speed than the N's without the lifting rails. 42 GPH for the N's @2100rpm

 

[jim rosenthal]

You are right. I was thinking of the turbo versions. My mistake. So the hp went up, AND the weight went down. No wonder it went so fast.

 

[bdewar]

Here are numbers from a Sea Trial of Knot Inn 53C QSM 11s 660 hp (Attached)
The Boat is for sale.

 

[tellico]

The N boats I have looked at (53C) have been 525 or 550 hp. The TI boats in the 650-750 hp range if I remember right. I think the N boats are ok to run on the pins at 2100 rpm. RSMITH has Ns in his 50C and will likely comment.

What's the meaning of "run on the pins" ...seen this a few times, so curious.

 

[saltshaker]

What's the meaning of "run on the pins" ...seen this a few times, so curious.

WOT or wide open throttle.

 

[Mike36c]

That's the #s. Lifting rails and one piece shafts will get you another 2kts with no HP increase. Even the 650HP TI boats won't get much more speed than the N's without the lifting rails. 42 GPH for the N's @2100rpm

Thanks, is that a 17.5 kt cruise without the lifting rails and one piece shafts? And I'm guessing a hull speed around 9kts @ one gallon per mile? I love the qsm11's but they might be out of our price range. I've heard rumors parts for the 1271's are getting scarce and expensive, is there any truth there?

 

[rsmith]

17.5 without any of that. You know my boat and it's basically the same hull and weight. I've trolled probably a million miles and @850 will give you 8.5-9 KTS and a ought 1KM /gal. After Walkers was destroyed we would run for about 2hours out of FTPierce then troll all the way to Marsh on the outside. The difference in fuel is amazing. But 1nmpg is a pretty solid #

 

[rsmith]

Just a thought while your looking. I prefished Chub Key on Ted Turners 53c "pocket change" back in the late 70's. It was one of the first to have prop tunnels. There was some problem with them and I don't remember what. I ran into the boat years later at Old Port Cove and the new owner had them taken out over at E&H. Just something to keep in mind if you run into one with the tunnels

 

[saltshaker]

If the naturals give you enough performance, then I'd say focus on finding the best boat you can afford. Dint worry about which engines as the 12V71TI are good engines. It's only when you get int the 870hp and up you see decreased service life. Even then they're good engines when cared for.