370 CUMMINS

sbeer · Post by **sbeer** » Tue Jun 06, 2006 12:48 am

I wonder what the #'s will be when you get fully loaded. Let us know. What do you cruise at 2500? Mike

michael · Post by **michael** » Fri Jun 09, 2006 9:10 am

Steve It was well worth it.I sold my 30 cuddy for 90,000 bought this boat for 45,000,put 100,000 into it and other than a few cosmetics i have a much bigger, better riding and practically all new mechanical from engines to plumbing, boat that i hope will last me a good many years. Mike at 2500 rpms i was between 23+25 knots.There was about a 25 knot south wind when i ran up the coast so it was hard to tell.I have not been out since but I here there are yellowfin in the wilmington

frank · Post by **frank** » Fri Jun 09, 2006 11:09 am

I have a 1986 33' Sportfish that I converted from gas to 370hp Cummings in 2004. We just returned from a 1600 nautical mile trip on the boat and our fuel consumption was 20 gph at 24.5 kts and 2400 rpm. This is a low cruise rpm for the engines. We have a ZF 1.5 gear and 21x22 4 blade props. The boat ran GREAT!

Sean B · Post by **Sean B** » Sat Jun 10, 2006 3:15 am

quote:Originally posted by frank I have a 1986 33' Sportfish that I converted from gas to 370hp Cummings in 2004. We just returned from a 1600 nautical mile trip on the boat and our fuel consumption was 20 gph at 24.5 kts and 2400 rpm. This is a low cruise rpm for the engines. We have a ZF 1.5 gear and 21x22 4 blade props. The boat ran GREAT! Frank Are those the Cummings 6BTA's? Those are some sweet performance numbers, congrats. If those are in fact the BTA's, do you have a lot of trouble maintaining the aftercoolers? I've been wary of aftercoolers because of the reports of them being a pain to keep up with, that they (being seawater cooled) clog up all the time. Real experience with them is of course better than dock talk Sean Burlingham "Island Time" 1987 Bertram 33 SF Melbourne, FL SBurlingham@cfl.rr.com

TBonedad · Post by **TBonedad** » Tue Jun 13, 2006 9:42 am

Sean - Michaels are 6bta's, with the aftercooler you're talking about. My 300's have the same aftercooler and it really isn't as bad as all that. I had one that had been neglected before I bought it and that was a mess, but I've learned that if you disassemble and clean them annually (this is far overkill according to Cummins recommended service interval)they are no problem. Disassembly takes about 5 minutes per side (15 the first couple of times you do it just because you're learning) have a radiator shop clean them for $50 and reassemble with new o-rings and lube and you're good for another year (or more). The hardest part is putting them back together and I spend about 30 minutes per side now that I know what I'm doing.

mikecobos · Post by **mikecobos** » Mon Sep 24, 2007 2:20 pm

I have 370 cummins in my 87 sport fisher. Have had the boat for 4 years. Was repowered in 95. I've put 1000 hours on it in so. cal. I don't know the gph but I do know that we travel to the grounds at night, I usually run at 11 kts. going out, fish and troll all day then run home at 22 to 24 kts. and I get a little better than 1 mpg. It wil do 30 kts. wide open.

michael · Post by **michael** » Tue Sep 25, 2007 5:06 am

Mike What gear,shaftsize and prop size do you have on your boat.My boat is a little slower.At 2500 rpm I cruise between 19+21 knots depending on my load and sea conditions. At wide open i can go 25 knots. I have ZF1.5 gear,1 3/4" shaftsand 21/19 3 blade props Thanks Michael 33sf

smanni · Post by **smanni** » Tue Sep 25, 2007 6:03 am

michael, I must be misreading something - are you saying that at 2500 rpms (cruise range) you are only doing 19-21 knots with cummins 370s. How? I run 18-20 knots with 275 CATS. 21x19 3 blade props - are you way underpropped? I have 20x22 with smaller HP and same trans ratio. Seems you should have much larger props? What am I missing?

Post by **dougl33** » Tue Sep 25, 2007 7:37 am

His prop diameter seems right, but the pitch is too low. Unless, of course, his boat is extremely heavy. I'm running 21x22's med cup with the same gear (ZF220a 1.54:1) on my Cummins 300's. I actually need to remove some cup/ pitch from mine this winter. I want to get 2900rpms. The injection pump on the port motor was leaking so we pulled it to have it re-built. I went out on Saturday to see if I picked up some RPM's. The results (2 runs in opposite directions with full fuel, 1/2 water, and 3 POB): Run 1 Port 2700 Stbd 2800 top speed was 28.5 knots. Run 2 Port 2750 Stbd 2900 top speed was 30 knots. No real change, except that the port motor now smokes much less at idle. I think this winter I'll go to a light cup on both props and take an inch of pitch out of the port one. Regards, Doug L. 1986 33 Bertram FBC Queen Elizabeth Marblehead, MA [img]http://www.bertram33.com/photogallery/p ... sabeth.jpg[/img]

smanni · Post by **smanni** » Tue Sep 25, 2007 9:37 am

Doug, Your running 21x22's with 300hp cummins - He should be able to swing a 22" prop if the hull clearance is there. Your props are bigger that his and he has 140 total more HP Your 300 HP are pushing you between 28.5-30 knots, he said hes maxed out at 25 knots. Even if he is heavier, he would have to have his painted line 8 inches below water to make that much of a difference. Something is not right there.

Post by **dougl33** » Tue Sep 25, 2007 9:49 am

Oh I agree. Something's not right. There are 3 of us here (Bill Dunlop, Frank B, and myself) that essentially all run the same exact setup (boat, motors, gears, props). The only difference being that Bill and Frank's engines are 330b's that are suposedly rated at 315hp, while mine are rated at 300hp. That being said, I've talked to a couple of different Cummins guys who've told me they're the same and that Cummins changed the way they rated HP. Anyway, all 3 of us get pretty much the same numbers. At 2400rpms, I get between 22.5-24 knots depending on load and conditions. Frank B and Bill get similar numbers. Regards, Doug L. 1986 33 Bertram FBC Queen Elizabeth Marblehead, MA [img]http://www.bertram33.com/photogallery/p ... sabeth.jpg[/img]

IRGuy · Post by **IRGuy** » Tue Sep 25, 2007 1:39 pm

We are pretty much the same performancewise, but FYI my props are 21D x 23 pitch. Frank B - IRGuy@aol.com "Phoenix" 1983 FBC Wilmington, NC

Post by **dougl33** » Tue Sep 25, 2007 2:39 pm

Any cup? Regards, Doug L. 1986 33 Bertram FBC Queen Elizabeth Marblehead, MA [img]http://www.bertram33.com/photogallery/p ... sabeth.jpg[/img]

IRGuy · Post by **IRGuy** » Tue Sep 25, 2007 4:38 pm

No cup.. Not sure if there might be a difference in performance due to the different CPLs.. mine are CPL 1928 I believe. BTW: it is finally in the mail! Frank B - IRGuy@aol.com "Phoenix" 1983 FBC Wilmington, NC

Captain Dan McClarren · Fri Sep 28, 2007 2:21 am

Mike, Here are the numbers from by B-33 last spring. Iwould think you should see even better number with the 370Bs Good luck with your new engines Bertram 33 Sportfisher Cummins 330B 315 hp ZF 220A 1.75:1 Prop Nibrel 24 x 24 — 1 3/4 four blade Idle RPM 650 Speed 5.2 kts. This speed can be reduced by engaging the trolling valves. RPM 1000 Speed 7.8 kts RPM 1200 Speed 8.9 kts RPM 1400 Speed 9.7 kts RPM 1600 Speed 11.6 kts RPM 1800 Speed 15.1 kts RPM 2000 Speed 18.1 kts RPM 2200 Speed 20.8 kts RPM 2400 Speed 23.4 kts RPM 2600 Speed 26.7 kts WOT RPM 2850 Speed 29.4 kts as per the vessel GPS All numbers above are with boat fully loaded with fuel and equipment and six persons onboard.