3208T CAT's; 1W5900 Arrangment

franklyprice · Post by **franklyprice** » Fri Mar 25, 2005 8:49 am

Peter, I just noticed that you stated you are topped out at 20 knots? Can this be true? Are you turning 2800 RPM @20 knots? If I'm getting this wrong , would you mind clearing things up ? It seems you've done a bunch of research but I still can't get an idea of actual speeds and RPM's from reading the correspondences with the guys you've spoken to. So to clear things up, what speed do you cruise at @ what RPM? What is WOT- speed and RPM? If you're topping out at 20 knots, something doesn't add up. Frank Price

smanni · Post by **smanni** » Fri Mar 25, 2005 1:45 pm

peter, I am no diesel expert - but take a look at some of the numbers that Jo sent you and double check them. When I bought my bought, the surveyor (who I know well and is a diesel mechanic, told me that for my 3208t cats - which are 270 hp (after the factory de-tuning that bertram did in all 33sf with cats) should cruise between 2350 - 2450 RPMs - with a top end of 2800 rpms with load and a no load max rpm of 3200. These numbers are significantly different than the ones you posted. Just double check because it seems that you are working under the assumption that your cats are 320 hp. I would say that MOST (not all) cat diesel stock bert 33's were ordered with the 260 - 270 hp cats that were detuned from a stock 300-320 horse factory cat. - Read Sean Burlington's posts where he has looked into this in detail and found out exactly what it would take to retune the engine back to 320 hp. I also looked into it and I don't think it is worth it. Sean Manni

Post by **Admin** » Sat Mar 26, 2005 7:55 am

This was what I could save from what banispeter tried to post: Here are the pdf's: Chart on 502 Gears David Sumich Bertram33.com Forum Administrator

banispeter · Post by **banispeter** » Sun Mar 27, 2005 2:40 pm

FranklyPrice: Yes, WOT is a bit north of 2800 and top end on my Garmin 128 and Raytheon 630 shows 20 maybe a touch more knits on a good day. At 2500 it's 18.8 or so. I know the boat is heavy (lots of cabin improvements, etc.) and the props are a bit too small 20x22 no cup. So, the answer is in the props. Will advise what I find out.

franklyprice · Post by **franklyprice** » Sun Mar 27, 2005 3:02 pm

Peter, I don't have diesels , so I can only go by the info I see from others, BUT, it seems like with only an inch or so less pitch than other boats with the cats, you should be running a bit faster. No wonder you're looking for more speed. It certainly seems like you could prop up a bit to get your cruising speed up into the 21 -23 KT range without over loading your transmissions, as long as you really do have the power to do so. I would think that if you are actually THAT MUCH under-propped now, you'd actually get the engines closer in RPM to the no load speed of 3200 and not just 2800RPM.Although thinking about it, I guess the power falls off pretty fast after 2800 RPM and maybe that's why it runs out of steam... So all things considered, why don't you just get your props tweeked for another inch and some cup and see what happens? A pretty cheap way to cut through all the advise and really see what happens. Frank Price

Post by **dougl33** » Mon Mar 28, 2005 3:31 am

Maybe a stupid question, but are you sure your tachs are reading correctly? 2800 rpms sounds just right, but the speed seems way too low. Do you have a tower? Regards, Doug L. 1986 33 Bertram FBC Queen Elizabeth

billb · Post by **billb** » Mon Mar 28, 2005 4:48 am

Peter: I have a 33 sportfish, 270 hp 3208's, 1.5 gears, 21x22 props, and with a clean bottom and running gear is curises at 21, 22 knots at 2400 rpm's, WOT is about a 2950 or 26 knots, as the bottom gets dirty and running gear gets fouled it slows down, if you have 320 hp you should get more speed than that...... Bill

banispeter · Post by **banispeter** » Mon Mar 28, 2005 3:19 pm

Bill: Read your post. With WOT at 2950 you are from what Iunderstand exceeding the gear spec. Our illustrious administator managed to post that link to the 502 gear spec I was emailed and it said 2800 equals 270 hp on the 502 gears (other way around - long day) so we are only supposed to be doing 2800 WOT under load and you, too, have a prop issue (listen to me now!) Anything more and the gear spec says we are overloading the 502's. I have no idea what's up. I have great difficulty believing Bertam would (1) buy 300 - 320 hp cats out of the box to then intentionally TUNE THEM DOWN to 270 hp when (2) they could have spent that labor money and potential voiding of the cat warranty on bigger gears and shafts and struts (making a bulk purchase 'cause they put 320's and bigger in the 37 and I think the 320 hp was standard or a diesel option on the 35). Just doesn't make management sense to me. Not at all. Someone would have had to sit down and (1) deterime 320 hp to be too much (right) and then do the cost accounting on the labor vs. part cost of shaft & strut in a bulk purchase and then (2) someone had to deal with cat on fooling with their motors. Just doens;t make sense to me. Not at all. Confused As Ever Peter L. Banis KNOT AGAIN Boston, MA

banispeter · Post by **banispeter** » Mon Mar 28, 2005 3:26 pm

So, anyway, I'm now on the www.braddandhall.com website looking for a new sleepsofa for the cabin to enjoy with that first bottle of Glenlivet 18 sometime soon.

franklyprice · Post by **franklyprice** » Mon Mar 28, 2005 4:00 pm

Peter, It looks like (to me anyway)that what everyone is trying to tell you , is that with the same gears and props and engines , they're running quite a bit faster than you are. It does not make sense that you are topping out at 20 KTS at 2800 RPM when the other guys are getting 26 KTS at the same RPM. The difference can't be cabin improvements. Or a tower. Are you sure you're not still tied to the dock? Nylon lines will stretch quite a bit you know.OK, seriously, One other thing they all have in common is that you don't hear about their gears exploding. Here are the facts as I see them; You are going way too slow for a given RPM , also if your engines make 270HP or 320HP , it doesn't matter, it's not making your boat go through the water as fast as it should. There can only be a few reasons for this. 1.Either the engines make less HP than they should and the props have been re-pitched less to keep them revved , or 2.you make the HP you're supposed to and the bottom is extremely dirty and the props have been re-pitched to keep the revs where they should be, or 3.Your tachs are both wrong and you're really revving to about 2400 RPM,and not getting full throttle, which seems unlikely if they're both about the same,or 4. You do have an engine problem AND your props are cavitating, again unlikely. 5. You REALLY ARE tied to the dock. I would bet five bucks that your props really aren't 22" pitch. Otherwise you'd be getting more speed at that RPM.Why you aren't getting more RPM is a stumper, but I also bet that the engines aren't making the power they should and someone has re-pitched the props to keep the revs in a range that's OK. The first thing I'd do is check the pitch on those props.The last thing I'd worry about is the gears breaking. My two cents, for what it's worth... Frank Price

Post by **Admin** » Mon Mar 28, 2005 7:17 pm

Dirty bottoms (quit your snickering!) can really drain your engines' ability to move the boat through the water. Seems like the most elementary thing, but are you on a regular bottom cleaning schedule? Have you had a diver take a look at things down there? David Sumich Bertram33.com Forum Administrator

Post by **dougl33** » Tue Mar 29, 2005 3:27 am

Peter, If you haven't done so already, I would spend the $25 and go to boatdiesel.com. Lots of good info over there. I'm almost positive that you do not have 320's in your 83. Something just doesn't seem right. Regards, Doug L. Regards, Doug L. 1986 33 Bertram FBC Queen Elizabeth

Sean B · Post by **Sean B** » Tue Mar 29, 2005 7:57 am

My money's on dirty props and/or bottom too. My boat is really sensetive to dirty props. Next I would get the props scanned

smanni · Post by **smanni** » Tue Mar 29, 2005 3:24 pm

I think Frank might be onto something here with point 5 - he really might be tied to the dock.

photo finish · Post by **photo finish** » Tue Mar 29, 2005 4:30 pm

just a stupid question??? are you sure you are going 20 knots... are you using gps for your speedo just asking in case you are relying on a spin wheel device such as a transducer. Tim Stamm Photo Finish 1981 33' Bertram FBC