55 Hatteras Re-Power

[True Grit]

Folks,
I have an older 55 Hatteras Coinvertible that I am thinking of repowering. It currently has ~900HP 12V71s and I was thinking of replacing them with 900 HP Yanmars. Anybody have e any input form experience or suggestions?

Best,

TG

[triniswordfish]

We run a 53 hatteras (extended 50) with the yanmar 8sy 900hp and they have performed really well we have about a 1000hrs on them. Great engines

[True Grit]

What kind of performance (i.e. rpm, speed and fuel burn) and roughly what price point (if you don't mind sharing)? Many thanks

[Questsportfishing]

the yanmars in that application is awesome for weight to hp *not to mention the fuel.... do me a favor though check your air intakes! those Yanmars love air and they need it to run .. or you could just let them vaccume out your boat through every nook and cranny

[Fortunate One]

I put a pair in a 48' express I'm having built. I can't wait to fire them up.

Here's a copy of a performance report. There are more available but I just can't find them at the moment.

http://www.kapelosdiesels.gr/LH2Uplo.../press_129.pdf


You may want to contact Mack Boring, the distributor. I'm sure they have the performance reports.

[Questsportfishing]

and great engine package choice. basically full of everything your trolling at idle and the fuel burns really cool at mid range. did you know that they used to pull lots of hp out of the v-8 903 cummins also? that was long ago though... the 2300 rpm engine range is better also in the larger hp. The Cats still got it together though also alon with the Mann's... ever seen a Viking go by at warp speed...???

[Shortfin]

Fortunate those are about the same burn numbers we get on a 45 Vik with 900 MANS common rails 28 knots is the sweet spot

[Fritz]

Fortunate those are about the same burn numbers we get on a 45 Vik with 900 MANS common rails 28 knots is the sweet spot

Mans!

[gradyfish265]

Mann 900's are a great engine and have a good fuel burn, also 1100's would be sweet if you want more speed, not a huge difference in fuel burn. The MAN V-8-900CRM weighs 3445lbs roughly, burning roughly 48gal/hr per engine. MAN burns are very accurate. Man V10 1100CRM's weigh 4081lbs and burn 57gal/hour, roughly 10 gal more an hour per engine, but most of the extra fuel burn will be at the gained higher speeds, so at cruise your fuel burns will be similar on a 900CRM and 100CRM engine, just with 1100's you can run faster if you wish to, and can cruise at a lower rpm to put less wear on the engine itself. I've run the same model boat with each engine, there is typically a 4-5kt gain on the same hull. Yanmar makes a great engine also, the 9sy 900 weighs 4636lbs,but that includes a gear weight, but that gear weighs 230lbs, making the Yanmar heavier then the MAN 900CRM. The Yanmar burns roughly 46gal/hr per engine. The Man will outperform the Yanmar by a slight bit, but they should be very similar, maybe a knot gain for the MAN900. If you would like more speed, the MAN1100 would be the best choice, you can pull back and sip the same fuel as either the Yanmar 900 or MAN900, but can go faster when you wish to, also it will give the boat more value if you resell. Boats today are going faster then theie predecessors, might give the boat more appeal down the road if there might be plans to sell in a few years. A 55 is a lot of boat, 900's will be ok for efficiency, but by nomeans will it be a speed demon. It all depends on the owner's use and priorities, to some speed is not necessary and resale is not an issue at the moment. If it were my choice, it would be MAN1100's. If not, between the Yanmar and Man 900's, it is a tough call, I think the dealer you will use for service should be the deciding factor, both are good engines. I have run more MAN boats then Yanmar's, but would be happy with either engine. MAN engines typically smoke a lot less then other engines out there, especially CAT's. I don't remember if the Yanmar's smoked a lot or not, hopefully someone can chamie in with more info on that.

[Fortunate One]

Tom,

You're going to have to send him an invoice after that post.

The availability of service was a deciding factor for me plus the people that we dealt with on the purchase of the engines were very helpful. They even gave me an upgrade to the computer for free.

I looked at C-18's, Volvo D12-800's and Yanmar 8sy-stp 900 HP Yanmar. We looked at available service up and down the east coast, fuel burn, speed and use of the boat in realistic northeast conditions and the best choice for us was the Yanmar. I got the trolling valve options too incase I want to take the crew striper fishing or maybe use it one day if the wind is non-exhistant while sail fishing.

I'm a repeat customer with Yanmar and I had a trouble free experience on the first go around so you got to go with what ya know.