1966 Byers drag boat

[ethyl]

I just bought this boat. It looks like pictures of old Sangers but I know little about drag boats. It is a flat bottom with 352 Ford, dual quad Holleys, through transom exhaust, Casale in/out v-drive and Velvet drive transmission. I have only taken it out at slow speed to check basics but was told that it porpoises around 55 mph by the previous owner. It has 1/4 " aluminum trim plates across the stern with turn buckles but what puzzles me is that the plates are not hinged and are bolted into the bottom flush with the bottom and I am wondering if these are adjustable as it seems that such would flex the plates away from the bottom or sress the bolts and cause leakage or breakage. Any information will be greatly apreciated. Thanks, John

[HOWARD O]

I don't know much about drag boats either, but I do know that they are called cavitation plates and from what I've seen of them, they aren't hinged, at least on the older boats. On some, the top of the turnbuckles were bolted to a rod that you could rotate "on the fly". I think yours is "set it and forget it" type and any adjustments that you'd make would be pretty small.

Be careful with that boat and I would suggest getting someone with some experience running one to school you. Flatbottom jetboats can be fairly forgiving, but you could get into trouble quick with a v-drive flatbottom if you don't have experience with them. :yes:

Got any photos? That sounds like a very early one!

[ethyl]

Howard, thanks for the reply. From what you and others say I do need to ease in on this one. Can't wait for Spring to see what it is all about! I will try to post some photos. Take care, John.

[ethyl]

I have a feeling this thing will handle alot differently than the 18 Classic.

[FlatRacer, aka BarrelBack]

At any given plate setting, a flatbottom will porpoise less at top end than at 1/2 or 3/4 throttle. Because of the angle of the prop shaft, when you put more power to the prop you drive the bow down more as you "push it over" its center of gravity.
With non-adjustable (on the fly, at least) plates it always a choice between having the boat ride well at cruising speeds but ride too wet at top end, or handling correctly at top end but propoising on the way there. If you watch circle races, you'll notice how the Crackerboxes which are not allowed to run adjustable plates do a lot of porpoising, whereas the other flatbottom classes which are allowed to run adjustable plates don't porpoise as much. This is because the Crackers are set up to run best at top end with minimal wetted surface so intermediate speed handling is sacrificed.
Of course, it's nice to have a foot override setup for the plate so you can avoid the porpoising at cruising and skiing speeds. An adjustable handle will save your calf muscle as well. I suggest you find a used set of adjustable plate hardware from a junked flatbottom and adapt it to your existing plates.
Eric

[ethyl]

Eric, sorry so long for a reply. Thanks alot for this information. I am anxious for good weather so I can see how she runs. John

[Craig S]

Nice Ford FE there!

[silverghost]

If that were my boat I would change the fixed cavitation plates to adjustable.
Check-out Glenwood Marine or Glen-L designs.
on the web. Click-on Inboard parts link. They have the new parts you need. Easy conversion!
Not very costly to convert!
It will be much more fun & safer to drive at all speeds!
You can go with hand or foot pedal cavitation plate control.
Cut plates & use piano style hinges with controls.
The way it's set-up now is for high speed full race running only !
This takes me back to the 70s & 80s !
I have many hours in this type of boat.
I had a family race friend killed in a similar boat.
Boat went in the air & flipped several times & he sadly broke his neck.
That was 25 years ago & his mother has never gotten over it to this very day !
I don't want you to get hurt !
It's easy to do in that sort of boat!
Any questions ~
Give me a call !
I'll try to help yu any way I can .
Brad Hunter
215 947 4676

[FlatRacer, aka BarrelBack]

DO NOT use piano hinges. There is enough give in the plates that you don't need to use any kind of hinge at all. The amount of play needed is probably less than in inch at the aft end of the plates.

Eric