bertram31.com

HELP--need to know original prop dia/pitch--Bertram cannot find record--30 flybridge 1983--crusader 454/350--velvet 1.52--1 3/8 shafts---starts & runs perfectly except max 3500 rpm, 28 smph---currently 3 blade 18 dia x 17 pitch-----thanks---mike

Extremely rare model, I doubt if anyone on this forum owns or even seen one!

I’d look if I could contact an owner from Yachtworld or any other site that may have one up for sale...there was one called Heyday in the US a few years back, I haven't seen more than 3 in the last 7 or so years, one of them in Italy. You may have more chance with the moppie model of which more copies were produced but I don't know if the specs are the same. I think Pascoe ran a test on it, perhaps you could find something in that article.
Good luck.

Mikey,
Familiar with the 30 Bertram, a few came thru the shop.
Those engines should turn 4400 wot.

You don't say if you have a cup or not.

Have you checked physically to make sure throttles mechanically opening all the way open? Your speed seems low vs rpm.

no cup--throttles open properly (Q-jet)--P.O. changed points to electronic (per-tronics, mallory distr)--odd that both engines behave exactly the same--I have not checked timing/advance nor camshaft lift--engines are fine except lack of top-end--they are ok at the speeds I travel, so I have not yet proceeded further---walleye fishing is too good to spend time on anything else. I would be interested to find if I'm over-propped----perhaps knowing the prop specs of a 28 bert or 31 hatt with the same gear ratio would be helpful.----thanks---mike

Mikey,

For what it's worth all specs I have ever seen on your B30 as OEM state 3 blade 18x17 props. Good luck, I'd rule out the easy checks first especially tach accuracy, throttle mechanical linkage, carb. operation and hull bottom condition.

If your overpropped it really does not matter what the original size was.

Motors get tired, bottoms get dirty, bags and rope get messed up in the wheels.
Tabs get stuck not retracking fully, shelves and draws get full


That said, if motors were running to up to required WOT prior to changing the points?
I'd start looking there.

New to you boat it time for a full tune up, compression test, read your plugs.
Make sure shafts turn freely by hand.
Verify the wheels are as marked and correct....it would not be the first time someone added pitch to a wheel and did not remark.

Mike, 28's came with small blocks and 1.5:1 reductions, but for what it's worth mine came with 17 x 16 wheels

boat is a time machine--dry storage at least 9 years before I bought it--except for pertronix, I think it's exactly as it left the factory--216 hrs--blue paint on all alt/water pump beltsno generator--no accessories except (working) trim tabs--bottom is clean, no excess personal items--I'll check compr/timing etc when I can--thanks to all repliers--very helpful--I'm now pretty sure props are original-----Mike

You need to confirm that you are getting proper advance on those distributors. Put a timing light and check.

Do not do anything else until you confirm this.