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ctkiteboarding
07-20-2006, 03:59 PM
ok 98 powerstar o/b,,, she jumps up and down in anything but glass and also jumps with people seated on the bench in back,,, i had a barefoot 200 with a similar problem and a phat sac under the bow helped,,, but this is a bowrider ,,,, nice, but lighter in the nose and i lose my seating if i put a phat sac up their,,, i installed a bobs machine hydro plate on the motor and that has helped but only if the motor if tucked in all the way,,, my next idea is a jack plate w 4 or 6 inch of set back,, i have reservations about this but some people have said it will help by lifting the boat up and others have said it will agravate the center of gravity and make it worst,,,, anyone have any ideas R

Granite_33
07-20-2006, 04:50 PM
There have been alot of comments on the board about having the hull hooked in the rear at the transom. I have not had this done, but hopefully someone here will comment to that.

Good Luck

ctkiteboarding
07-20-2006, 05:04 PM
hooked as in glass work ??

G-man
07-20-2006, 05:12 PM
Are you are trimming the engine up some when your running or do you think it shouldn't need to be trimmed?

Granite_33
07-20-2006, 05:30 PM
hooked as in glass work ??


Yes, fiberglass work on the running surface at the transom.

http://www.tmcowners.com/teamtalk/showthread.php?t=10101&highlight=hull+hook

Start there. It can be done.

ctkiteboarding
07-20-2006, 05:30 PM
i tried every possible option w/ trim as well as 500lbs of ballest up front ,in the middle ,, and in the rear,, still hard core bow porpusing, the only improvement has been the trim plate from bobsmachine.com that has helped but only abit and only when tucked all the way in R

JDK
07-21-2006, 02:34 AM
Go back to Bob's website and look up their 'transom wedges'.
These will give you 5 degrees more trim down. This may be enough to help you out.
More set-back isn't going to help.
What engine/prop do you have? ...and can you 'drive through' the porpoising as the boat accelerates up to top speed?

ctkiteboarding
07-21-2006, 11:55 AM
i was thinking about the wedges,,, the o/b is a merc and i have three options for props all of them high five s/s 19 ,21, 23 pitchs im using the 21 currently,, no driving thur the issue , it gets really bad if i try to power thru it ,,,,

bigmac
07-21-2006, 12:30 PM
Sounds to me like there just isn't enough transom angle to allow you to tuck the engine in far enough to keep the nose down with that particular engine. Those transom wedges may indeed do the trick in providing enough angle and they're cheap. If they don't do it, I'd be inclined to install trim tabs rather than permanently modifying the hull with a hook. Simple to install, and they'd allow side-to-side trimming. These things run $500-$600. I don't know what you'd have to pay a fiberglass guy to glass a hook in the hull.

I don't see this as a prop issue.

http://www.overtons.com/graphics/products/medium/25558M.jpg

sixysixss
07-21-2006, 12:45 PM
Smart tabs/Trim tabs may help. Porpoising is usually caused by being trimmed too high. Check out the forums at iboats (http://www.iboats.com/bbboard/html/mainpage.html). There is a lot of information there on outboard and I/O boats.

JimN
07-21-2006, 12:55 PM
Why can't you get the others to ride farther forward. The problem is weight distribution and adding weight at the rear makes porpoising worse.

ctkiteboarding
07-21-2006, 02:36 PM
i agree with the weight issue but the seating is where the seating is and will have to stay,,, i like the trim tab idea where did u get that pic of the tabs i see here R

bigmac
07-21-2006, 02:58 PM
i agree with the weight issue but the seating is where the seating is and will have to stay,,, i like the trim tab idea where did u get that pic of the tabs i see here R

Overton's (http://www.overtons.com/modperl/overtons/order/items2.cgi?request=aisle&catnum=2C13D). Rumor has it that the Lenco units are best. No clue as to what size you might find optimal.

I agree with you about the seating. It's not too much to ask IMHO to have a boat and engine combo that will be usable without making those kinds of compromises. I rebel at the concept of assigned seating in order to make a boat functional.

For $24, I'd add the wedges too - it might minimize the need for trim tab use.

ctkiteboarding
07-21-2006, 03:09 PM
just ordered the wedges , lookin into the lenco trabs for [placement and fit etc thanks guys for the input ill drop a report in a few R

sixysixss
07-21-2006, 04:51 PM
Also check out the Smart Tabs (http://www.nauticusinc.com/).

ctkiteboarding
07-21-2006, 07:02 PM
i measured the only area that i can mount a tab system and the space is super limitied ,,, did a search and found a manual adj/ tab system by step and trim on iboats,,http://www.iboats.com/mall/index.cgi?keywords=trim%20tabs&session_id=683146250&cart_id=795605227&list_time=1153519277&view_id=38477, they will fit and i ordered them ,, should be here in a few we will see R

jet_ifr
07-24-2006, 11:54 PM
I had the same issue on my '93 BF200 (and on my dad's 1953 Queen Mary 18' flat-bottom river boat). For the BF200 I actually took the balast from the front (2 12" subs/box/amp) and moved them into the trunk. It solved the bow-bounce immediately, but it still bounces if the boat is lightly loaded.

Below is another solution you might want to try before you drill holes...it worked on the '53 but I haven't tried it yet on my MC.

If you look at where your outboard attaches to the transom, you'll see a series of mounting holes on the outboard trim mechanism either above or below where the transom bolts go through the hull. A cheap (albeit "heavy") solution is to try adjusting the motor "up" one set of holes. This will put more of the hull in the water at higher speed, but you may have to mess around with props to achieve the same top-end you had prior to the engine adjustment.

The process above worked for us with the '53 and a 150hp Merc (boat was designed for a 70hp way back in the day). I'm contemplating an engine change in the near future, and I'm probably going to put a jack-plate on the BF200.

Good luck.

ctkiteboarding
07-31-2006, 09:51 PM
update ,,, i installed the trim tabs and the boat is rock solid at all speeds and conditions it has totally changed the boat and the ride ,,, im still goin to install a jack plate but the will be for shallow water running issues,,, thanks R

bigmac
07-31-2006, 10:25 PM
update ,,, i installed the trim tabs and the boat is rock solid at all speeds and conditions it has totally changed the boat and the ride ,,, im still goin to install a jack plate but the will be for shallow water running issues,,, thanks RGood news. Did you put the transom wedges in too. Anyway, the tabs sound like a nice, cost-effective solution.

ctkiteboarding
07-31-2006, 11:56 PM
no wedges yet w/ the tabs i run the motor w/ more trim ,so the current angle seems to be perfect,,, i have them and maybe when i install the jack plate i might try them out but today the boat was perfect ,looking forward to tommorow,, im going to take abit of the tab trim out and see how she handles,, i had them at a neutral positon and it was abit better ,,today at full trim down and she was really nice im hoping i can trim the tab up abit and keep the hull as efficient as possible ,, it was a good day R :)

Hoosier Bob
08-01-2006, 12:28 AM
Not read entirely but I think Big M has it! Trim Tabs should be the cure all and can be adjusted according to load and position of load. Would the infamous Doel Fin work on an out board? I think the trim tabs are the way to go and should be alot less and more flexible than cupping. Just my 2 cents which are only worth a penny!Sounds to me like there just isn't enough transom angle to allow you to tuck the engine in far enough to keep the nose down with that particular engine. Those transom wedges may indeed do the trick in providing enough angle and they're cheap. If they don't do it, I'd be inclined to install trim tabs rather than permanently modifying the hull with a hook. Simple to install, and they'd allow side-to-side trimming. These things run $500-$600. I don't know what you'd have to pay a fiberglass guy to glass a hook in the hull.

I don't see this as a prop issue.

http://www.overtons.com/graphics/products/medium/25558M.jpg

schwartz36
09-28-2006, 04:41 PM
Any photos of the tabs installed on your boat?