Bertram33 User Forum

My boat is called 33 Megabites. Named such for my work with computers and my love of fishing (don't need to explain the 33 right?). You can see a picture of it on the images page (your boat can be there too!). Specifics: Twin Mercruiser 7.4 liter 454 CID V8s (330 HP) Tuna Tower (with redundant controls) Outriggers Bait tanks (1 stern, 1 bow) 6kW Westerbeke genie (no more Onan!) Garmin 225 GPS/Plotter Lowrance LMS-350A GPS/Depth/Fish finder Furuno 1751 Radar Icom IC-M57 VHF (redundant in tower) Autohelm ST 6000 Autopilot w/ remote (very cool!) Fireboy halon fire extinguishing system (in engine boxes) 6 SS bridge mounted rod holders That about sums it up. All in all, totally awesome! David Sumich Bertram33.com Forum Administrator

What year? 1986 33 Bertram FBC

DOH!!! 1986 - Sportfisher David Sumich Bertram33.com Forum Administrator

Thats funny. I have gas motors as well, but my manaul says they're Mercruiser 340 hp not 330. I've seen this before, but I can't understand it? It looks like you have a tower. What rpms/speed are you cruising at? What are you getting for WOT? 1986 33 Bertram FBC

I cruise @2200 rpm, probably about 15-16 knots. WOT (at least as far as I like to go) is about 3800 rpm, 24-25 knots. David Sumich Bertram33.com Forum Administrator

Hey Dave, my 82 FBC has 350hp/454cid crusaders. I run at 3000 rpms to get 16 knts cruise w/ 20x19 3 bladded props. And the fuel burn is horrendous. My orig.4.5kw Onan still runs great, even w/ A/C on. What kind of fuel burn are you getting at 2200rpms and with what props ??? Thanks Ken

Shoot, that should say I cruise @ 2800 rpm @ 15-16 knots, not 2200. I can't remember the props size off the top of my head even though I just read it this last weekend. [:D] David Sumich Bertram33.com Forum Administrator

quote:Originally posted by Admin I cruise @2200 rpm, probably about 15-16 knots. WOT (at least as far as I like to go) is about 3800 rpm, 24-25 knots. David Sumich Bertram33.com Forum Administrator

According to the bertram owners manual the original props are 21x20 three blade. operation: 1000 rpm 5.3knts@3.44gph (total fuel consumption) 1500 rpm 7.0knts@5.6gph 2000 rpm 9.8knts@10.32gph 2500 rpm 15.0knts@17.6gph 3000 rpm 17.9knts@26.4gph 3500 rpm 23.5knts@36.48gph 4000 rpm 28.2knts@48.16gph I can tell you these mumber are right on the money according to my gps and the gas pumps. My sportfisherman seems happiest at 3150rpm, just before the four barrels kick in. At 3150 she making 20.5 to 22 knts depending on the wind. She really comes alive at that speed.The manual also lists specs for the 555 cummings.-Rob

If you check out the Mercruiser owners manual, you will find that these engines call for a wot of 4200-4600 rpms. I recently had some work done on my spare props as I was only getting 3700 rpms at wot with a speed of 26-27 knots with full fuel, water, and 4 POB . I like to cruise at 75% of wot, but 2775 was barely getting me 17 knots. My old props were really overloading the engines. I know a lot of guys don't like to push their boats, but its a good idea to do it every so often to make sure the engines are hitting their rated rpms. If they're not, then you could be looking at problems down the road. My engines have 1000 hrs on them, were tuned in May, have good compression, and don't burn a drop of oil. Since I was getting a good top speed I figured the problem was the props. My props had been 3 bladed 21x20's with no cup. The shop (Haskell and Hall) cut them down to 20x18's with a #5 cup. This resulted in the same 3700 rpms at wot and I actually picked up a bit of speed (27.5). I gave the shop back the props and they knocked out some of the cup to bring it down to a #2. Now I'm getting 3950K at wot when fully loaded and the speed stayed the same at 27.5. Actually, when the boat was light (1/2 fuel and water) I hit 29.3 knots. I had never had it go this fast before. Not bad for a 22K pound boat. Now I'm cruising at 3K and getting 18-19 knots. I think I will try taking some more pitch out over the winter to try and get closer to 4200 when fully loaded but I'm done playing the prop game for this summer. Regards, Doug L. 1986 33 Bertram FBC Queen Elizabeth

Doug, my 1978 Mercs list on the valve cover a WOT of 3800 rpm. I think my manual must be the same as Robs.Beginning of season, I was getting 3950 stb & 3900 port. After my enforced layup, it's only 3400 on stb & 3200 port.That was with an EXTRA heavy load & the front canvas up. My port carb developed a vacuum whistle just before my surgery so the stb engine may be carrying the load. As soon as I can get some more use out my right arm, I'll pull it & put new gaskets & adapter plate. Plate was installed on the 1998 rebuild when the carbs were switched to Carter AFB's. Hopefully I can get back up to 3900 rpm. Al 1978 33 FBC NITES OFF

My crusaders have 238 hrs on them and they will turn 4200rpm WOT. Thats with a full tank of fuel three people on board and no canvas. my generator is also not installed. I'm wondering how the 6.5kw onan will effect the numbers? The props are the original 21x20 three blade.-Rob

Rob, Did you have your engines rebuilt, or are they new? What are you getting for speed at 4200? I'm not sure what the 6.5 weighs (I have the same gennie currently installed), but I'll bet you're rpms will drop a bit when you reinstall it. Do you have a tower or 1/2 tower? Regards, Doug L. 1986 33 Bertram FBC Queen Elizabeth

Doug, The starboard engine was new out of the box in 96. The port had a new long block, risers, elbows,heat exchanger, fuel pump and carb in 2001. at 4200rpm my gps shows about 32 mph or about 28knts. If you run these boats at high rpm they seem to go burn up motors at least the gas boats anyway. Theres an 1989 33 bertram sportsman (bertram called it the sportsman when they extened the cabin of the sportfisherman), it's been at the club since it was new and I've seen the motors replaced several times. As for the top rig I guess you could call it a half tower, I call it a hard top. -Rob

Rob, Thanks for providing the rpm/kt/gph info. I'm looking for a 33 SF and was curious about its speed and economy. Basically wanted to know how it compared with the 28 I used to have. Talked with several 33 owners and got a wide range of numbers that didn't seem to be consistent. I acquired a Bertram spec sheet (Nov '87) that provides performance info for the 33 SF. According to the specs, the 33 appears to be very thirsty, consuming 38 gph at cruise (3200 rpm). The specs also indicated a limited range of 207 stat miles. Cruising speed was indicated to be 23/25 mph, which I believe is pretty much in line with your numbers at 3150 rpm, but cruising gph was quite a bit higher than your calculations. The caveat to the performance data shown on the spec sheet was that the numbers were for a new boat running under ideal conditions. As they say, mileage may vary depending on driving habits and condition of the vehicle. For what its worth, Bertram had the prop size for the 33 SF as 23X26. Thanks again for posting your performance specs. Don quote:Originally posted by robjb3 According to the bertram owners manual the original props are 21x20 three blade. operation: 1000 rpm 5.3knts@3.44gph (total fuel consumption) 1500 rpm 7.0knts@5.6gph 2000 rpm 9.8knts@10.32gph 2500 rpm 15.0knts@17.6gph 3000 rpm 17.9knts@26.4gph 3500 rpm 23.5knts@36.48gph 4000 rpm 28.2knts@48.16gph I can tell you these mumber are right on the money according to my gps and the gas pumps. My sportfisherman seems happiest at 3150rpm, just before the four barrels kick in. At 3150 she making 20.5 to 22 knts depending on the wind. She really comes alive at that speed.The manual also lists specs for the 555 cummings.-Rob 83bert33sf