20ft SeaCraft With Twin V4's??? Just Thinking OL..

[Dunk]

Anyone tried this?? Of course finding a 20ft and rebuilding/widening the transom to fit twins would be the first thing. Go with 25" engines and raise the transom to 27-28" in the center would clear up allot of the wash over... The question is...is there 60mph in those hulls. Will they get up on the steps and run?

[SEAFARI]

Here ya go
http://classicseacraft.com/Archives%20Page%202.htm

My 20MA did 54mph with a 200 Yam Pro-V. You could
feel the bow lift after 50. 60 shouln't be a problem
with twins.

[Finster]

Thats one for www.screamandfly.com. I would think yes only because I've talked to the second owner of the Seavette when there we're 2 235's on it and it did in the 70's.

If Hermco would make a bracket for it I am sure the hull would take it. I would be more confident having that buoyancy for the weight of the motors for that 7' beam.

[Ryan]

dunk ther was a 20 with twin merc2.5s on it down in the keys a few years ago. It sat real low of course and i saw it listed in the boattrader about a year ago. also in the potter years they would factory rig twin 70 hp hope this helps

[Mike_D]

The seafari I have listed for sale. Had twin 50's when we got it but as I recall when we removed them in the early 80's they we not that big. Nothing compared to the size/weight of v4's. There is sill enough room although. I would think it would work out.

[Dunk]

dunk ther was a 20 with twin merc2.5s on it down in the keys a few years ago. It sat real low of course and i saw it listed in the boattrader about a year ago. also in the potter years they would factory rig twin 70 hp hope this helps

Now we're talking... I don't know how long ago you are talking about, but when I was living in the Keys in the late 80's there was a 23 in Islamorada with a pair of 2.5 Bridgeport Offshore 260's. I was running one of the headboats for Robbie at Holiday Isle on the night trips. I was coming up Rt1 just at the end of Lower Matecumbe at the Lignumvitae Key channel where it runs from Robbie's up to Papa Joes along RT1. These two guy's had just run the wheel ditch up behind Matecumbe and were lining up to run up to Papa Joes. I was pacing them, speedometer in the truck was reading 80mph and that 23 Seacraft was walking away from me.
You have to see that boat run to believe it. I never did see that boat again. I'm not sure if he was local or not.

I've seen some wild rigs built once you put USCG regs behind you.. Even a 75mph+ 20ft Whaler Outrage with a pair of 175 Evinrude Ficht's on it.

Finster..as you guy's get to know me you'll find that I'm dead set against bracketed outboards. Unless the boat was designed from the mold up to handle the engine(S) 30" behind the hull most don't run the way they should. I think it's an especially bad idea on seacrafts because you are putting the best part of the wave cutting deep vee in the air where it won't do you any good. Yes, patching up an old stern drive with a bracket for an outboard is good way to save the boat because you are removing a 1000lbs of sterndrive and engine. Boats like that were designed to handle the weight on the transom. My next rule is nothing under 23ft get's a bracket. Moving the engine 30" behind a boat like 20ft Seacraft that was never designed for it, I think is foolish just to gain a little space in the rear of the boat. There's too much "Notched Transom" fear running rampent on the internet. The biggest reason boats sink from water over the transom is not keeping your deck access plates water tight. 90% of the boats I survey I find bad orings or broken access plates that will let water flow into the bilge.

[gbf03]

Dunk
In Ft Lauderdale there is a potter built 23 with twin 250 yammis on it.

[strick]

Finster..as you guy's get to know me you'll find that I'm dead set against bracketed outboards. Unless the boat was designed from the mold up to handle the engine(S) 30" behind the hull most don't run the way they should. I think it's an especially bad idea on seacrafts because you are putting the best part of the wave cutting deep vee in the air where it won't do you any good.

I'll call you out on this one dunk [img]/images/graemlins/wink.gif[/img] While I agree with you that the boat must be properly designed or structurally capable of holding the motor on a bracket I disagree that it changes the running surface and puts the wave cutting portion of the boat too high in relation to the water. At rest a good bracket provides enough flotation to offset the center of gravity difference. It may take a bracketed boat a second longer to get on plane then when before it was bracketed.....but once on plane the running surface/water contact area should be virtually the same. Here are a couple pics of my boat before and after the bracket. Looks like I actually gained a little flotation. I also have some running shots that show the boat is riding pretty close to where it was when it was a notched transom. I dont have a way of loading them right now because this computer does not have the right software.





Strick

[Trayder]

Strick-

Was the first picture taken in Freshwater and the second in Saltwater?

[Fr. Frank]

Dunk is right, and so is Strick. It depends upon the hull, and especially on the amount of rocker in the hull. In a previous life, I spent some time as a test pilot (strange name, that) for Wellcraft, testing engine and propeller combinations for new boats, or new factory power set-ups for renewed models.
For instance, Wellcraft chose NOT to make a 19' bracketed OB version of the Scarab hull after testing showed that that configuration porpoised continually without putting K-planes down in the water at 10+ degrees at all times - not enough hull length to rocker.
Here's a rule of thumb we came up with, which Wellcraft follows to this day. If you set the hull on the ground, balanced from side to side with the keel line at the transom touching the ground, at 45% of the vessel LOA the hull must be in contact with the ground. In other words, there must be no appreciable hull rocker in the aft 45% of the boat in order to put a bracket on the hull.
The last Wellcraft production hull to violate this rule was the 1990 26' Scarab OB center console. Rigged with a B-bracket for twins, it came factory equipped with either twin Yam 130's, or twin Merc 115's. On plane, the boat porpoised, always. Testing w/ V6 OB engines showed the aft CG made it worse. When we tested the same hull with transom mounted engines, the problem was greatly reduced. The hull had a 37% rocker point.
I have seen many 20 SeaCrafts with bracketed OB's, and all seem to run fine. A 20' Seacraft has a rocker point GREATER than 60%. So does a 23".
On the other hand, my 20' Seafari seems to like it's transom mounted V6 Merc [img]/images/graemlins/cool.gif[/img]