35 bertram need help and advice

jww · Post by **jww** » Mon Nov 01, 2010 4:21 pm

in march i purchased a35 bertram in galveston,hurricane ike boat was on the hard for a repower motors,trans,gen.burned up in a warehouse fire nite of hurricane boat was on craiglist for many months so i bought it to good a deal to pass on. iwent into this with a open mind as to what was needed new power,trans and other repairs. however now i need help or advice.this boat is to be used for charter so some things are needed 1.extra fuel 2. relocate gen. 3.fresh water 4.AC can i locate a 50 gal fuel tank where gen was and on port & starbord 2- 20 gal fresh water tanks or will this make stern to heavy? move gen under salon sole for more protection from saltwater if i put all 3 tanks in stern it will add @ 800lbs of weight.i have repowered with 3208cats & zf220a 1.5 trans, new shafts struts,shaft logs ect. rebuilt engine beds with glue lams & alum. angle.some help or advice would be apericated i hope that i am on the right track but if NOT PLEASE TELL ME. thank you JW WATSON PS for the past 6 months i have been looking at what have been done t 33735 bertrams WOW it all looks so good .i just hope i can measure up thanks jww

CB35 · Post by **CB35** » Mon Nov 01, 2010 5:02 pm

Kind of on the right track; but you are flirting with a bow heavy boat. You moved 300-400 pounds from well behind the CG to well in front. When you get low on fuel look out it could turn into a bow steering beast. Please don't tell us you also mounted a 200 pound liferaft on the bow. Good luck; but you are on the edge of having a terrible handling boat in a following sea or a big inlet. Mine has 3208's with the genny in the cockpit. I can run a big following hands off. That is what a deepV is suppose to do. You did not say what HP on the Cats. You load her with all that weight, ice, 6-8 guys gear and they better be 375's at least.

jww · Post by **jww** » Tue Nov 02, 2010 4:36 am

charlie the fuel load and water willbe in the stern just in front of the rudder shelves no 200lb life raft on bow 3208 are 320hp should i be able to use alittle more trim tab and be fine thanks jww

butch · Post by **butch** » Tue Nov 02, 2010 5:11 pm

I have a 1974 35 with 3116/350cats moved the gen set star side front of motor and both a/c units port side front of motor put a new 40 gal water tank back were bertram had it and keep 150lbs. of tools etc on top of water tank. the boat is not bow heavy and still run great in a following sea

CB35 · Post by **CB35** » Wed Nov 03, 2010 5:35 am

Butch do you know how little those 3116's weigh?

CB35 · Post by **CB35** » Wed Nov 03, 2010 5:45 am

You will need almost all the trim tabs to get the bow down while cruising for best speed. If you forget the tabs are nearly all the way down upon entering an inlet with a big following sea you may get the ride of your life. Been there done that and my boat is stock from the factory with 3208Cats. When cruising offshore in a following I still use tabs to get best speed. At 18-20 kts the 35B just punches through the backs of the waves. When you enter an inlet most often you can't run it at 18kts, at least here in NJ. Too many slow boats, fishing in the inlet boats, or no wake inlets. I still run them pretty fast, but you don't want the tabs down if you have to slow down for any reason.

butch · Post by **butch** » Wed Nov 03, 2010 3:11 pm

Charlie, It's been a while since my repower if my memory is right 3116 come in at about 1500lbs without gears the 3208 375hp under 2300lbs without gears.a wieght differance of about 1600lbs per set. I also have a steel cradle system for eng. beds (500 to 600 lbs) / 2 D8 a batteries moved to engine room and gen battery in eng room(say 200 lbs)teak floor in the cabin and v berths (400 lbs?)2 a/c units and gen. set in eng. room / plus all the tools,oil, etc. etc. I'm not sure if my teak cockpit has any effect on the balance. (but is also very heavy)MY plan was to add weigh to the stern if needed via extra fuel or a fish box that i could add water if we became lite and had no fish (it is still a big empty hole) I have run this boat for over 15 years with this set-up never had any bow steering problems still runs great in a following sea I know of 3 other 35 berts with gen. set in eng.room all running out of manasquan. Butch

CB35 · Post by **CB35** » Thu Nov 04, 2010 3:00 am

Yes Butch I had a ride on one sounding very similar to yours several years ago and it was the worst boat I have been on. It also had 3116's at 350 HP. The guy had to add a huge "kill box" that he had to keep full of water or ice or fish. he added the "kill box" after the transom fishbox did not add enough weight.The boat would nose over running at 2500 rpms. I have personal experience with another 35B that had to have 1000 pounds of lead placed at the rudders, 500 pounds a side. By messing with the C of G you get an unstable boat that needs lead or water just to keep it in trim. This is best way to waste fuel and loose cruising speed. Be careful. By the way a stock 3208 Cat 35 Bertram already has full length steel engine beads.

butch · Post by **butch** » Thu Nov 04, 2010 12:58 pm

Charlie, Sorry you had a bad ride . I personal have fished on several 35 berts with the gen.sets forward of port motor and no added weight in stern.also fished a 33 bert 3208 boat set up with gen forward.I would have to wonder what was wrong with the boat you rode on. If your thinking we only go when not windy I assure you we have had our share of beatings.I'll say it again I and other 35 owners have not seen any bow heavy problems. butch

butch · Post by **butch** » Thu Nov 04, 2010 1:09 pm

last post wrong info gen sets sit front star motor

ckuppens · Post by **ckuppens** » Sun Nov 07, 2010 11:25 am

Charlie What is the weight difference between the Merc 454's and the 3208's? I ask because my boat isn't great in a following/quarterning sea. I put the tabs all the way up and it is still pretty sloppy.

CB35 · Post by **CB35** » Mon Nov 08, 2010 5:50 am

The center of weight of my 3208Cat 35B is 12'6" as measured from the inside the the transom towards the bow. 12'6" puts the center of weight in the center of the 3208 Block. The center of the boat is about 18'6". Therefore the center of weight is some 6 feet aft the center of the boat. Anything placed in front the the motors adds weight to the bow. 35B are supposed to be stern heavy and the trim tabs are a must for setting cruising trim. Moving AC's, gennys, and other crap to the forward engine puts the boat in a bow heavy configuration period. This will affect the ride in following seas. A good friend of mine had a 35B with gassers. He got a on my several years ago coming home from the Bertram AC Rendezvous. His comment was the my 3208 powered 35B was a totally different ride. The said the boat rode very smooth, less rocking and pitching. This is what happens went you put 4000 plus pounds of cast iron in the in the belly. At quick google search says the 454 weighs about marine weighs about 1150 pounds.This means a 3208 boat has about 2000 pounds more weight in the belly. Bertram put a lot of time and money into designing the 35B. Moving stuff around causes problems. The lighter the motors the larger the effect.

ckuppens · Post by **ckuppens** » Mon Nov 08, 2010 4:18 pm

Thanks... makes sense to me.

IRGuy · Post by **IRGuy** » Mon Nov 08, 2010 7:22 pm

Charlie... Maybe this is a dumb question.. but how did you locate the center of mass of your boat?

CB35 · Post by **CB35** » Tue Nov 09, 2010 7:49 am

It is not a dumb question. I have all the original paperwork on my boat. Bertram spent lots of engineering time on the boat that the paperwork attests to. There is a blueprint showing blocking placement, hull deadrise at several stations along the length of the hull, shaft angle, prop position below the hull center-line, center of weight, various heights above waterline for gunnel, flybridge ect. They even showed the weight the travel lift should show for front and rear strap placement. There is a complete table/graph on speed vs rpm, vs range for three different cruise weights in kts and mph. Fuel tank gauge as it relates to gallons left in the tank. They include how to measure from the transom to the waterline to determine draft for a given load and more. Over the years I have talked to guys who went to four blade props. Not one of them could match my stock Bertram configuration; 20"X22" nibral cupped. I have yet to find any improvement for more speed at a given rpm for a given weight. For more speed you need to throw stuff off the boat or add HP and torque. And torque is the name of the game. Changing fuel settings to get 320 HP out of a 300HP 3208 Cat is not going to buy you a thing. Oh I may have found one or two things. I went to a walker type air cleaner. Next I want add cold air to the engine room and make sure the engines are getting enough air. If you look at any Cat manual you can see pretty quickly you can gain power (or not lose power) by keeping the engine room cold. Most folks have lost or just kept all the blueprints. In fact I even have a separate binder that has all the wiring diagrams for the boat and every option. That binder is about 24 inches long by 11 inches and about 3/4 inch thick. Pages upon pages. The center of weight may be different for 454 boats, or 555 cummins boats or 3208 boats. I still bet it is safe to say the center weight needs to be near the rear 1/3 of the boat. I can make mine bow steer with full tabs running a following sea. I also have to use most of the tabs to put the bow down for normal cruise. This gives best speed and the ability to power through a pretty good headsea. I have had guys in 31B's try to stay with me in a headsea. The outcome was not even close. I have been on too many "F"ed up 35B's to know it is easy to get them bow heavy.