2010 Nordic Thor Prop Help

[ChrisKoller64]

We purchased a 2010 Nordic 27 Thor about a month ago with a 26 pitch 4 blade Bravo prop. Boat will run about 68 mph with 5 adults and 3/4 tanks at 5200 rpms. After seeing some of the other Thors with the same power running about 85 we thought maybe it was the prop. The 26 spins on the top and the motor can rev to almost 5800 rpms and I used the merc prop slip calculator to the tune of about 22%. So, we tried a 28 pitch signature 4 blade and the boat wouldn't plane out with the same fuel and people aboard and that left us clueless. The boat has a Merc 525 with a Bravo XR upper and IMCO shorty lower running 1.5 gears. Any ideas are appreciated.

 

[EBT531]

are you sure your tach is accurate? I thought the RPM range for a 525 was 4800-5200. 5800 seems way high. What is your trim at? Maybe you are over trimming allowing the prop to air out and increase rpm's?

 

[ChrisKoller64]

Tach is accurate but it did have quite a bit of trim when it was reading 5800. We're still learning a lot about the boat as its our first cat.

 

[spark2678]

I just purchased a '09 Thor 27' open bow with 525 and XR. Came with a 28P prop, we ran it last weekend with 3 adults, 3 kids and lots of gear. Gets up on plane, takes a bit, got it to 62mph at about 4600 rpms with full tanks. Going to a 26P this weekend, hoping to get it to around 70 with 5100-5200 rpms. In the summer I think that's about all it will do, especially with Bimini up. I have read somewhere 94 mph but I don't see how that is possible, maybe with a 600. Maybe 1 person, 1/4 tank, winter time, no Bimini, no gear. I think the 525 is 5350 rpms before it hits the rev limiter.

 

[Livewire Fabworks]

Only way you would be hitting 5800 rpm is if the ecu has been flashed by someone. I think they hit the limiter at 5200-5300

 

[02HoWaRd26]

I just purchased a '09 Thor 27' open bow with 525 and XR.

I know we saw you twice this weekend, and believe we also saw the op as well.

 

[ChrisKoller64]

Okay so I'm glad its not just us that's having a hard time getting to where other people say these boats have ran. We were up at Pirates until about 1pm on Saturday and then shot down to steam boat. We'll be out again this weekend!

 

[ChrisKoller64]

I just purchased a '09 Thor 27' open bow with 525 and XR.

I think you will like the 26. We get on plane quick with 5 adults and pretty loaded down with gear. With a little less weight you should be right around 70 mph like we are.

 

[EBT531]

Okay so I'm glad its not just us that's having a hard time getting to where other people say these boats have ran. We were up at Pirates until about 1pm on Saturday and then shot down to steam boat. We'll be out again this weekend!

I think you'll find "most" people state a speed their boat runs with 1 person, barely any fuel, in the winter, going down river and a non-gps speedo. LOL Under normal loads, summer heat and GPS they lose 10-15mph.

 

[spark2678]

Was out this weekend. 26p Bravo 1 prop worked great. Hit 5100rpm at 75mph with 3 adults and around 3/4 tank of fuel. Probably had a little more. Between 55-60 is sweet spot at 3500-4000 rpm, that is where I like to cruise. The exhaust out the back of the sponsons is loud as hell too when I get up in mph. LOL, I'm old.

 

[ChrisKoller64]

Nice! We had 6 adults in our boat and got it to like 68mph at like 5200rpm. Thinking the boat just like doesn't like the weight as its a night and day difference with even just 4 people compared to 6. The exhaust definitely starts screaming as soon as you're above like 4200rpm. It'll be interesting to see how the boat runs once it cools down and isn't loaded up with people and gear.

 

[02HoWaRd26]

I think 85 mph with a stock 525 is very very high reaching. With pristine conditions and set up i could see hitting 85 but that’s not running 85.
The 525 is an impressive animal but it’s still only 525 hp, and they are still 27’ boats.
This weekend i ran my 15 3/8” 26p Cutting Edge and my boat really liked it, mine isn’t the same but is a similar set up. Saw 76 at 5300 with about 65-70 gallons of fuel and big ice chest etc but only the wife boy and i.

 

[ChrisKoller64]

Update on this: boat is completely different loaded down vs 2 people. We took it out Sunday AM after fixing a weak impeller and it jumped on plane and got to 5400rpm with the current Bravo 26 @ 72mph. We'll be trying the 28 pitch signature next time we get up early and don't have many people onboard.

 

[02HoWaRd26]

Update on this: boat is completely different loaded down vs 2 people. We took it out Sunday AM after fixing a weak impeller and it jumped on plane and got to 5400rpm with the current Bravo 26 @ 72mph. We'll be trying the 28 pitch signature next time we get up early and don't have many people onboard.

Not to say you won’t like it but i wasn’t a fan of the Signature on a cat. They feel heavy is the only thing i can say. I have a 28 in my boat as I’m typically running the Max 5 26p on my boat. If you see us this weekend as we will probably be at Pirates for a while Saturday, hit me up. Can try the Bravo 28 in comparison to the Signature if you want.

 

[ChrisKoller64]

Not to say you won’t like it but i wasn’t a fan of the Signature on a cat. They feel heavy is the only thing i can say. I have a 28 in my boat as I’m typically running the Max 5 26p on my boat. If you see us this weekend as we will probably be at Pirates for a while Saturday, hit me up. Can try the Bravo 28 in comparison to the Signature if you want.

Replying way late on this but we tried the 28 signature Christmas Day when it was cold, no bimini, and 3 people and it didn't work much better than the 26. I read somewhere a 5 blade prop is the key on these hulls but we still have a ton of slip. I think we'll be eyeing a 28SS with twin OBs soon.

 

[LBZRCKS]

Replying way late on this but we tried the 28 signature Christmas Day when it was cold, no bimini, and 3 people and it didn't work much better than the 26. I read somewhere a 5 blade prop is the key on these hulls but we still have a ton of slip. I think we'll be eyeing a 28SS with twin OBs soon.

Do you have pics of the rear of your boat and bottom? Maybe you have a different bottom than @spark2678

 

[ChrisKoller64]

Do you have pics of the rear of your boat and bottom? Maybe you have a different bottom than @spark2678

Unfortunately I don't but I believe the bottoms were updated in 08. He has an 09 and we have a 10 so I believe it should be the same.

 

[02HoWaRd26]

Unfortunately I don't but I believe the bottoms were updated in 08. He has an 09 and we have a 10 so I believe it should be the same.

Aren’t these the Talon bottom with some slight changes, that didn’t work out so well, so the later Thor’s went back to the original Talon hull?

 

[ChrisKoller64]

Aren’t these the Talon bottom with some slight changes, that didn’t work out so well, so the later Thor’s went back to the original Talon hull?

Not sure about that one. We went out Saturday and it didn't skip a beat in the white caps. Thoroughly impressed with the handling and the faster we went the better it was.