MILD THUNDER

iTrader: (3)

A while back I was interested in some of the discussion regarding the straight bottom cigs and their porpoise issues at higher speeds. Saw guys doing the "wedge" mod to the hull, which I imagine helps keep the bow down and the porpoise under control.

My thought was maybe , rather than try to keep the bow down, maybe something to help keep it "up". I was watching a video of a straight bottom 38 Scarab that had big power in it, the boat ran straight, and dry at higher speed. Watched some videos of straight bottom 38 cigs, and noticed at higher speeds, they often appear to run fairly "wet", and a bit of porpoise. Some you can actually watch the boat lift and then land again on and off the inner strakes over and over. I asked some of the straight bottom scarab guys to measure their inner lifting strakes.

From the edge of the transom, to the end of the inner lifting strake, it was 10ft on the scarabs. On the top gun, it was 14ft. One hull measures 37'7", other measures 37'6", but the scarab has 4ft more lifting strake.

Curious if anyone has ever tried extending the lifting strakes on a straight bottom Cig

MILD THUNDER

iTrader: (3)

This straight bottom 38 scarab had side by side 850-950hp blower motors, #5 drives. Boat ran 108 if i recall.

bigfarmer

Tres Martin would be one guy worth talking to about this!!

F-2 Speedy

iTrader: (6)

Am I reading this wrong ? or are the boats flipped ?

MILD THUNDER

iTrader: (3)

From transom edge to end of lifting strake, its 10ft on the scarab. 14ft on cig.

F-2 Speedy

iTrader: (6)

I see, so you're thinking shorter strakes eliminates the porpoise ?

MILD THUNDER

iTrader: (3)

The scarabs have longer strakes, 4ft longer.

Im thinking maybe the cigs with bigger power, are outrunning the short strakes so to speak. The props are lifting the hull off the strakes, but cant hold the boat up very long , so the porpoise starts happening.

We all Know why a 388 hustler is so fast with mild power, they have full length strakes all the way to transom. Or pad bottom hulls.

Prob not a mod for a 70mph top gun, but maybe for the guy shooting for 90 plus ? Idk just thinking out loud

F-2 Speedy

iTrader: (6)

Im confused , on the previous post you said they were 14' on the cig ?

offshoredrillin

he said 14' from the back of the boat, he is asking if a longer inner lifting strake would make the boat ride out of the water more and less of a wetted surface, the short answer is hydro dynamically speaking, yes it would, but being as the boat would be riding higher the propensity to chine walk and fall to the sides instead of down in the front would be more, also with a longer lifted surface it would change the X dim slightly. I dont think that it would be hard to do, didnt Dan do something like that on his?

MILD THUNDER

iTrader: (3)

Dan didnt extend the inner strakes. First, he had someone remove some of the outer strakes, in therory to let the transom settle. Then he had them put back on, and did that tres martin wedge thing. I think the wedge helped the porpoise.

Speedy, the measurement i am speaking of, is if you take a tape measure, and measure from the transom edge, to the end of the inner lifting strake. the longer the distance, the less strake you have.