fishead

I have a 1990 30 Shadow cat with twin 300 pm's.Greatest rough water boat I have ever been on and I love it.I was wondering if any of the guys that ran the shadow had any set back and if not did anybody run any type of external water pick up.I have my motors bolted to the transom and run into water pressure and temp Problems.I am also running 28 bravo 4 blades that have been labbed and had vent holes drilled.Great all around prop but would anything else be advised.
Mark

X-Rated30

Nah - No one on this board knows anything about Shadow Cats. (I think you'll get your answers. )

I am interested in the lines of the boat. It looks very similar to my Spectre. Anyone know if they share any DNA?

Semper Fi

T2X knows. He was in Powerboat Magazine recently

Sean

i owned the second or third one out of the mold for a short time. it was a 1981 that was owned by Joey Detore. it raced a couple of races as HMS Dea Won with some experimental Mercury motors.

when i got it, i powered it with a pair of 2.4 bridgeports and it was pretty slow... i didn't do much dialing in with it, but i did mount my pickups on the transom because i had some overheating problems. I also did not run any setback. the motors were bolted to the transom and it probably ran high 70's at that time(1995). kept it for a couple of years and finally "gave" it away...

fishead

Boat cruises at around 70 at 4 to 4300 Rpm depending upon the load.I have had it to 85 with six people and 3/4 gas at about 5700.I know it has more but run out of the water pressure when I start trimming.I love the boat but just want to dial it in some more.

T2x

Are you running...Sportmasters?

What water pressure are you seeing? Are you getting horn signals on pressure or temp?

What Engine spacing are you using (length of tie rod?)

Props..... pitch and diameter?

Have you weighed the boat?

T2x

fishead

I knew you would chime in.First of all this is a kick A$$ boat.Whatever you guys did to design this should be used today.Although there are faster 30's out there they cannot keep up with me when the water gets rough.I boat on lakes were it gets very snotty on the weekends and I never,I mean never have to back off on the sticks.Now
I am running sportsmaster
Bravo 4 Blade props that have been labbed and vent holes 15 or 15.25 X28(hard to tell on the diameter but I think 15.25)
57 inches on the tie bar
Have not weighed it yet
When the motors are trimmed all the way in the nose cone is only 1 inch from Transom.I am thinking the transom is so close that it is disrupting the water at the pickups.Just my thought and maybe some setback would put them in cleaner water.Also get some porpise at around 80 and having trouble driving through it .I cannot trim too much and the pressure drops.At the max trim I use now (which is 2 units on the Indicater) I am running about 7 to 8 psi and the temp is 150.Whern I trim past that the temp rises rapidly towards 180 but I always trim down before it gets past that.Once I go down the temps come down in a short tim.I guess I am too chicken to see if the horn goes off.Impellers are new and water shoots out the pee hole about 5 feet and it real strong.
Mark

Gladhe8er

My dad had the first Shadow ever built(original Black Duck). That one fell apart, so he got a new one(picture below). He did not have any set back. Unfortunately I don't know too much else about the boat...I was too young.

T2x

Okay....... You will probably solve most of your water problem with a small setback (8-10")....I would not go further than that....If the condition still persists try grinding two small notches directly ahead of your lower units about 1/4" deep 4" wide and maybe 3" forward on the pad (be sure to cover this with glass when completed). As to the porpoise (The "Linder Hop")... This will require a wedge or tunnel tab to correct...(sponson tabs didn't do much).......

Your Engine placement is spot on.

Have you tried Cleavers......?

T2x

BROWNIE

Attention T2x. Is that the 8 yard or the 12 yard model. I can't tell from the pic.