Bertram33 User Forum

Sorry about your ribs. Let us know how everything turns out with the sea trial. Good luck. Mike just plain addicted

Boatdiesel's propeller calculator says our boats would be best suited with a 22" Diameter x 21" pitch, cupped prop. Force the calculator to figure for a 21" prop and the recommended one is 21x22 cupped. Force the calculator to figure for a 20" diameter prop and the recommended one is a 20x23 cupped. I've got my spare set re-bent to 20x23 with #5 cup, but haven't put them on yet to see what happens. The shaft calculator says we need minimum 1.5" Aquamet 22 shafts for a safety factor of 5, the minimum recommended. I'm really interested what your numbers are with the 21x23 props: 1) RPM at WOT 2) speed at WOT 3) speed at 2400 RPM ...please post them when you have them. Hope you can get 2800 WOT with that prop. You should, I think you are probably near the limits with the 21x23. I'd take it real easy climbing up big swells or running rough inlets with those props. I think that after the change you are quite under-shafted. Yes, I mean your boat, not you (got to fit a shaft joke in there somewhere) Sean Burlingham "Island Time" 1987 Bertram 33 SF Melbourne, FL SBurlingham@cfl.rr.com

Well here is the #'s At wot under power with 3/4 tank fuel and full water and 3 people on board 2850 rpm. This was done on the river heading into a pretty stiff wind. Enclosure was zipped up on bridge. Topped out at 29 kts. Cruise at 2400 rpms on the same senerio 24kts. At wot the engines had not hit the pins. Suggested that I could actually go up 1/2 to an inch in pitch with out overloading. How ever when mechanic was told about the size of the shafts he admitted that had he known that before the trial he would not have had me open it up. Felt that 1.3/4 was needed for a good comfort zone which I am in total agreement. I agree that in a large following swell there is a high probability of snapping the shaft with the existing set-up is expected. System has been like that since 1987 and has been run in some pretty rough stuff. The main question is why would bertram put a system like that in the first place. Mike just plain addicted

Thanks Mike. Now I know exactly what I'll get if I decide to do the upgrade to the 21x23 props and 1.5" A22 shafts. It seems to me that what you're quoting is really the fastest setup I can have without changing engines. Nice to know the cruise speed numbers. Do you have flowscans? I wonder if you still get the usual 0.8 - 0.9 gallons/nM with the larger props. I would guess consumption per mile would not change, would just get there faster! Thanks again. As for why Bert did it, well, I guess they were not immune from making mistakes. Stupid humans! Sean Burlingham "Island Time" 1987 Bertram 33 SF Melbourne, FL SBurlingham@cfl.rr.com

Actually thinking about it more, I probably won't reach your top end speed without changing my max fuel rack settings as was earlier discussed. But I should attain your cruise speed, and would have to see about the WOT RPM's, if I didn't get 2850 with my "rated" 260 HP engines then I'd be screwing with the injector pumps. I think maybe I have next winter's major Project. Thanks again Sean Burlingham "Island Time" 1987 Bertram 33 SF Melbourne, FL SBurlingham@cfl.rr.com

If you look to up the pump, I do believe you can do that with out removing it. Correct me if I am wrong but to boost the out put of the pump all you have to do is replace the cylinders and pistons which can be done on top. Of course you will have to get injectors to match. This is what a cat tech told me when I asked about a pump rebuild. Its easyier than pulling it. Check it out for yourself and let me know if this is correct. Mike just plain addicted

That's funny, my CAT guy seems certain that it is easier to replace with a new/rebuilt injector pump assembly that has the bigger pump groups, instead of changing existing one. Injectors are the same for all 3208T's, whatever HP number they stamped on them (260-320). Sean Burlingham "Island Time" 1987 Bertram 33 SF Melbourne, FL SBurlingham@cfl.rr.com

If you got the money to put a new or rebuilt in, thats the way to go. Its alot cheaper to just drop the bigger piston groups in place. Everyone to thier own likeing, I guess. As far as the injectors, the parts guy at ransom cat told me he had to have the # off of the injector to insure I got the right ones. Why would he ask that if all injectors are the same with hps from 260 thru 320? Mike just plain addicted

Sean: let me know how much the pump and injectors cost...I might wanna do that to mine... Bill Beeson 33 bertram RAZZMATAZZ

I understand the largest shaft the stock 502 gears can handle is a 1 and ahlf inch shaft so going up larger means new gears. the 5050A's I am told fit and can take up to a 2 inch shaft but that is serious money (I was quoted 18k for all of the materials and work involved).

You're right, all I know for sure is that the injectors are the same for all HP ratings for my particular engines. I don't know for sure if other years/arrangement numbers came with different injectors. From what I've experienced, at least here local to me, the CAT parts guys are all stupid lazy jerkoffs. I know that's harsh but man these guys deserve it. They should be able to look up your arrangement number on their database and know exactly which injector you need. Getting them to get off their butts and actually do that is something else. On my engines the injector part number was 1W-5829 and was described as "Nozzle A." quote:Originally posted by sbeer If you got the money to put a new or rebuilt in, thats the way to go. Its alot cheaper to just drop the bigger piston groups in place. Everyone to thier own likeing, I guess. As far as the injectors, the parts guy at ransom cat told me he had to have the # off of the injector to insure I got the right ones. Why would he ask that if all injectors are the same with hps from 260 thru 320? Mike just plain addicted Sean Burlingham "Island Time" 1987 Bertram 33 SF Melbourne, FL SBurlingham@cfl.rr.com

quote:Originally posted by billb Sean: let me know how much the pump and injectors cost...I might wanna do that to mine... Injectors were expensive, $120 each x 16 = $1920 for both engines. They are supposed to be replaced every 3000 hours, which is exactly how many hours my boat had when I got it. I noticed a big difference after the job: they smoked a lot less and are much smoother running. Make sure you adjust the valves too while you're in there. I never priced the injector pump. I won't do that until I get larger shafts. Sean Burlingham "Island Time" 1987 Bertram 33 SF Melbourne, FL SBurlingham@cfl.rr.com

quote:Originally posted by banispeter I will change to 21 x 23 with a #3 cup nad have me scanned. Peter, Was just reading through this old thread, and am wondering if you ever scanned and changed out your props before the snow got to you. ? Sean Burlingham "Island Time" 1987 Bertram 33 SF Melbourne, FL SBurlingham@cfl.rr.com

Sean - did you ever try out your spare set of 20x23 cupped props yet?

Hoping to get 'em on just after the new year. Lots of projects half done right now Sean Burlingham "Island Time" 1987 Bertram 33 SF Melbourne, FL SBurlingham@cfl.rr.com