View Full Version : Hydrostream, weight vs handling

06-26-2001, 09:07 AM
Noticed a handling problem this weekend. The boat is a Vision (Similar to a VKing but with a 9 inch pad and a foot and a half shorter in length) with a Merc 175 6 inches back and about 1 1/2 below pad, 26 Chopper (70.1 GPS), no cone. Usually the boat handles great. What I mean is I usually have two full 5 gallon tanks on the passenger side and sometimes a passenger. By the end of the weekend those tanks were pretty near empty of course and there was no passenger. This is were I noticed the quirk. The boat would tend to want to fall to the starboard side. Was also getting more hop then usual, even a bit at full speed. The tach only goes to 6 grand and it was buried deeper then usual. Very hard to balance on the pad. It would only take very light corrections. A small ripple or a little to quick with the wheel and the rear end would begin to move around and it would loose bite droping the nose a bit then chine walk bad. A little scary actually. When I got into shore I checked all the bolts, cables, links and the prop. Everything was OK. This is just my second summer with the boat. Like I said, usually I can drive it flat out at about 70 with only little corrections. Maybe getting used to the boat I've never driven it that hard that light. I'm anxious to try it again with a full load of fuel (Not before pay day though!). So my question to you Hydrostream pilots is it it normal for the handling to deteriorate as the boat gets lighter? Was I experiencing a bit of blowout? Wide pad running to high out of the water? Thanks for any advice. Glenn

06-26-2001, 10:04 AM
Hey Glenn, Yea the lighter they get the the more violently they will react, but it really sounds like a little prop blow out problem is occurring. The shorter the gear case (ie. no nose cone) the lower the blowout speed. This also depends on the prop. Usually a stock gear case run on the surface will make it to about 80. But again setup and prop could easily lower this to 70.

06-26-2001, 10:46 AM
I'd leave this one to the experts, but here's what I've observed in my limited experience:
I drive a 20 footer with a 200. Yesterday, I noticed that it is much more SCARY to drive at 70+ when I'm alone, as opposed to when I'm carrying passengers. When I was alone, it had a stronger reaction to small steering adjustments, and was more "floaty" on the pad. It seems easier to keep flying level with some load in the boat.

06-26-2001, 01:04 PM
Thanks guys. I forgot to mention that the steering had to be cranked a little harder to the left then usual. Didn't really notice any torque on the wheel but suppose I wouldn't with the Teleflex NFB system in there. Last year I had no water or temp gauge so I was running 4 inches below. Put both gauges in at the beginning of the season. I slowly adjusted the plate up 'till I was at the top. This brings me about an 1 1/2 below pad. Surprised that the motor will run 140 degrees with 25 PSI at that height with no cone. Perhaps I am reaching the limits of this lower unit, or boat (pad too wide at 9 inches). The motor is a 1978 Merc 1750! I don't think a cone would be worth it because I'm pretty sure the motor doesn't have the grunt to get me into the speeds where it would be a real benefit. I'm not sure. I did manage a 71.1 GPS with a borrowed 29 SRX. It seemed manageable but I'm sure the boat was heavier for that run. Glenn

06-26-2001, 04:10 PM
I am no expert, but I would think that a pad that is 9in across could not be termed as "too wide". The narrower the pad is, the more the tendancy to chinewalk by design. Also the lower the wetted area and better the efficiency. Allison boats are some of the most notorious for chine walking and I think that some models are on a 10.5" pad. Also, the higher you jack the motor, the stronger you will feel the paddlewheel effect of your propeller. That could increase the crab angle of your gearcase and make it a little harder to steer in one direction. It could also act to try and pull you off of the pad.


06-27-2001, 01:13 PM
...is that your balance changes as fuel goes lower. Try shifting some weight around to compensate, and get some side to side balance. This should help too.

07-23-2001, 05:56 PM
Moving it to the port side will balance your weight a little, W/ no passenger, some people put a sand bag in the passenger seat to help compensate. Never had prop blow-out, sorry can't help you there. But I ran the v-king in a ton of different set-ups/weight configurations. Takes seat-time to get better. Have fun.

07-24-2001, 10:35 AM
As one who has been through several blowouts in a Hydrostream, I speak with some experience. It does sound like you are getting a little bit of blow out. What propeller are you running?
My Valero pad boat has blown out anywhere from the low 80's to the high 90's and is fairly gentle either way. The boat will simply set the nose down and gently go left.
I would work with weight balance. Move that battery to the port side a little bit and try to balance the boat for top end. I would only add weight as a last resort. Try moving the weight around that you have before you add more. I also moved my front seats in towards the center of the boat and that helped the top end attitude considerably.
Another thing to consider also, is that the lower the motor is mounted the harder it will be to drive at speed. Try blocking off the top water intakes and you might even look into a blow-out ring for the rear lip of the gerarcase to give it some more length.

07-29-2001, 10:59 PM
Just got back from 2 weeks of vacation and quite a bit of boating. Solved my high RPM fuel starvation problem with a Holley Red fuel pump. Motor is as high on the plate as she will go. About an 1 1/2 inches below the pad if I recall. I'll have to check again. 6 inches back. Still get over 25 PSI at max speed. Prop is a 26 Quicksilver Chopper. Battrie is on the starboard side. You guys are right on about weight placement, and it doesn't take much. Alone and when the fuel load was right she handled like a dream. The Vision is running consistent 72's on the GPS now.


07-30-2001, 10:30 AM
Glad to hear it Glenn. First thing I do is add a Holley. Now others like 84 have had great luck w/ the VRO. Me? My luck is bad -- like gum on the shoe. Sticks to me and well, pushing the gas in vs. pulling it made more sense to me. Still going to install the fuel pressure gauge.

Moving the battery sometimes means moving the gas tank, if it is permanently attached. And if the fill hole is cut, piping can be a chore.

Glad to hear success!

08-01-2001, 10:57 PM
Hey Glenn,

Where did that Slip-on LWP I sold you go?? I had it to 85 mph with no problem. When running alone in my Viking at 100 mph, I would experience a slow oscillation. The bow would rise and tilt slightly to port then tilt to starbord and drop. This was like in slow motion. When the bow came down you could feel the speed dropping then it would start lifting again. I was running a Bob's / stock lower with a 32" Cleaver 3/4" above the pad. With a friend in the back seat, It was rock solid. I left my battery and trim pump on the drivers side. Didn't want to hack up the boat to relocate everything.

Ever think of adding ailerons????

08-02-2001, 07:38 AM
Hi Ron. Still got the LWP of course. Problem is with the jack plate I have I can't get the motor high enough to take adavantage of it. Had my friend drive the boat while I was in the back looking at the lower unit. Water line is right at the first inlet hole. I'm still pegging the pressure gauge and running cool. To go higher I'll have to remount the motor on the plate. That means drilling the plate. Holes won't line up on the old bracket. That's a Fall or winter project I guess. I've got that solid mount problem so maybe I'll tackle both at the same time. I figure once I get the motor higher and put the LWP back on I'm going to be looking for a bigger prop too. All of which makes me wonder 'cause I've been told by Anthony and Sean(for both of whom 80 is a walk in the park in their respective boats) that my Vision was real spooky near 80. I need some seat time in a V-King or Vector to help me asses the way the Vision is handling. Hmm....


08-02-2001, 08:39 AM
If you are looking for some seat time in my Vector come on by, you will find it handles even better than last year when you were in it. Jackplate was definitly a great investment. Sorry I didn't get a chance to take you for a ride when you were up in the spring.

08-26-2001, 09:35 PM
Are not included and are required for most boats.:D