1982 Bertram Cat 3208 Exhaust

el_89 · Post by **el_89** » Thu Dec 14, 2017 10:09 am

Good afternoon everyone, I have a 1982 Bertram 33 Sportfish with twin 300hp Cat 3208's. My exhaust comes under the deck of the boat to a large muffler. From there the exhaust splits and a 3" pipe runs straight out of the back of the boat and a 4" pipe comes out the top of the muffler, runs up the gunnel wall and goes out the side of the boat. My question is, is it possible to combine these into one exhaust pipe that either runs straight out the back of the boat or to an angled outlet on the side at the water line? The black exhaust soot stains the sides of the boat and I would like to eliminate that if possible. Thank you all in advance!

Capn Tony · Post by **Capn Tony** » Fri Dec 15, 2017 4:37 am

I don’t think I can answer the split exhaust question. I run a pair of Cat 3116’s that have their own individual mufflers and exhaust strait out the back; each 6â€�. I’d like to address the sooting. I too used to soot up but do so no longer. It took me a few years to get there but finally after tweeking new props (21â€� 4 blade I forget the exact pitch) and tuning the engines they run very clean. Can you get 50 or more RPM over rated at WOT? What kind of oil are you using?

franklyprice · Post by **franklyprice** » Fri Dec 15, 2017 1:46 pm

The best way to do what you want is to remove the old mufflers and install new ones with a single 5 or six inch outlet . The old mufflers are quite large and you'll have to cut them apart to remove them and the new ones can be a bit shorter to fit without cutting the boat apart. There is a bulkhead in the way , so the original mufflers were installed when the boat was built before the top half of the boat were installed. The shorter muffler will be a bit louder but not too bad. You could cut the back half off the existing mufflers and glass a new back onto them but since they are essentially partially submerged when the boat is at rest, I'd recommend new ones. As Tony is recommending, you may be able to get the exhaust clean enough with some service work and propping to make the job of changing mufflers unnecessary.

Capn Tony · Post by **Capn Tony** » Sat Dec 16, 2017 5:00 am

I didn’t mention that the Roamin’ Beauty was a one owner gas boat with side exhausts. The previous owner converted to diesel and changed the exhaust to go straight out the transom. The first year I had the boat I removed the deck & re-cored it. At that time I also re-built the exhaust using the same mufflers but new pipes and bronz thru hulls. The mufflers lie neatly along either side of the fuel tank. When I’m loaded with fuel the exhaust ports sit half way submerged.

el_89 · Post by **el_89** » Wed Dec 20, 2017 4:42 am

Thank you both for your input! I do need to get my props re-tuned as well as my motors. I just purchased the boat this year so I have some work to do to get her where I want. Frank do you know where I would be able to find those new mufflers that only have a single outlet that goes out of the transom?? Also I am running Rotella Triple T 15-40 oil. Thanks again!

Capn Tony · Post by **Capn Tony** » Wed Dec 20, 2017 12:38 pm

I am running rotella straight 30W

franklyprice · Post by **franklyprice** » Fri Dec 22, 2017 4:17 am

This might not be the exact length you need but it's close. https://www.fisheriessupply.com/centek- ... d-mufflers

el_89 · Post by **el_89** » Fri Dec 22, 2017 6:04 am

Good morning Frank, I was searching the internet and found a muffler that says "prevents water surge" which I am assuming means they can be used below the waterline and will not allow water to back flow into the engines? Please correct me if I am wrong....Anyway I will attach the link if you could please let me know if you think they would work for my application. Thanks! http://www.go2marine.com/product/97405F ... 1237697615

franklyprice · Post by **franklyprice** » Fri Dec 22, 2017 1:29 pm

I'm not familiar with that brand , tho they do look pretty good. Apparently they have a swinging check valve in them. I like the idea but wonder if the check valve failed, how would you know? It's generally understood that any muffler provides some resistance to surge.. Also, looks like they're out of the 6" , the 5" would probably suffice.Some guys with boats that have more potential for surge than our boats will install a surge tube at the forward end of the long straight run, I've never seen one on our boats but is always good insurance.

butch · Post by **butch** » Fri Dec 22, 2017 1:46 pm

Frank, I was involved with the gas to diesel conversion on Tony's Roamin Beauty including the exhaust.. if memory is correct we patched the muffler where it went up to side exhaust and fiberglassed 6" nipples on both ends ,,,, I have a 35 Bert. That did not have side exhausts and increased the in and out of the muffler to the recomened 6" for my 3116 cats the same way. I recall making a jig to glass the fiberglass pipe to the muffler. Could still have a set off original 4" in storage . Wasnt a big deal and mine have about 3000 hours without a single issue. I'm sure Tony could take a look or remembers from when his deck was out.

butch · Post by **butch** » Fri Dec 22, 2017 1:48 pm

Frank, sorry post was for the guy looking to convert.

butch · Post by **butch** » Fri Dec 22, 2017 1:54 pm

El 89. Believe mufflers Ar veratone? Or something like that. Boat is a 74 and was original mufflers

el_89 · Post by **el_89** » Fri Dec 22, 2017 2:48 pm

Thanks everyone. Just spoke to Hightide Marine and the first thing he said was "those side exhausts were nothing but problems, and no one likes them because they stain the sides of the boat". He confirmed that what I am looking to do is feasible. Frank, I agree I don't know if I completely trust those mufflers to keep water from back flowing. My plan was to put exhaust guards on the outlets for added insurance. I see that the 6" is out of stock. Do you think the 8" would be too much? I see the centek website recommends 8" for a 300hp diesel but that seems excessive to me...

franklyprice · Post by **franklyprice** » Sat Dec 23, 2017 9:41 am

I think that must be a miss print, 5" will probably be fine, 6" will give you added insurance, 8" is crazy big. I've never seen that size on one of these. I have the 6" on mine and they're pretty big, can't imagine anything larger on a 33.

el_89 · Post by **el_89** » Wed Jan 17, 2018 10:22 pm

Does anyone know for sure if 5" exhausts would be sufficient for 300hp Cat 3208's? The 6" models appear to be discontinued.