bertram31.com

finally got her in the water but was short lived, we put 20 gallons of fuel in each saddle tank and took her out. the main tank was not in the boat yet so she was very light. there were 4 of us and she hit 40 knots with no sweat and had more in reserve. the new axiom screen is unbelievable, cannot wait to get back in fully fueled down and run her for the day

Remind us of which version of the 31 you own and the specs on power/propulsion. 40 knots is very fast; I topped out at 33 kts with the Yanmar 6LP-STE 315s, 2:1 gears and 20X23 4-blade props.

SaBurke,
My 1961 31' Express did 41.8 MPH on the NorthStar 951X when the boat was repowered in 1997. That was with full fuel (170) gallons, 25 gallons fresh water, empty holding tank 6 gallons, soft top up and 22' Rupp single spreader outriggers in place. Speed runs were done in Lake Worth between Old Port Cove and the Blue Heron Blvd Bridge. Wind SW @15 slack tide. 2' Chop. Three people on board. The 41.8 MPH was into the wind, down wind was 42.6 MPH.@ 4400 RPMs. She started to chine walk at 40 MPH. Plenty fast enough for anything I ever wanted to do.

I used to run from Lake Worth inlet to the Loran tower in Hobe Sound to sailfish. Most days I would run up and back @ 30 MPH at 3000 RPMs and burn 22 GPH each way used to take around 30 minutes from the slip in Riveria Beach Marina to Loran Tower. I found if I ran 2000 RPMS she did 20MPH, at 2500 RPMS she did 25MPH. 3000 RPMS she did 30 MPH . The engines were 7.4L 454 CID 330 HP detuned to 310 HP FWC big Block Throttle Bodied Mercruisers with Hurth 63A * degree down angle trannies 3 blade Nybral 17x19 bronze props, 1-1/4" Monel shafts that were 106" long from coupler to end of shaft.. The boat had a low profile strut system with only 9.5" of clearance between the strut barrel center to the bottom of the boat, with a set of small struts just aft of the shaft exits to prevent shafts from whipping. The shaft lay out was original from the Bertram factory in 1961. Bob Lico runs a low profile shaft set up if I remember correctly, the lower the shaft angle the faster she goes.
Glad to hear that your finally in the water Good Luck.
Pete Fallon
PS I am officially retired as a marine surveyor due to medical issues with my right knee per doctors orders. Waiting to get another knee implant sometime in March in Baltimore.

Pete

You are correct. Bob lowered his engines so the pans are just off the hull allowing him to flatten out the shaft angle allowing him to fun flatter and with a better top end. For a 31 he would normally be considered over powered but he got it to work. Shift the weight aft and the shaft angle had a huge impact on the boats performance.