Converting a 1978 20' MA

Cheap Thrill · #1 11-13-2012, 07:56 PM

I am in the process of rebuilding a 20' MA, its now stripped to the stringers and am thinking of making it into a straight inboard with a tunnel drive. My brother owns a 20 ' Penn Yan it can go anywere!! It draws 9" of water and he had it 20 miles offshore. Has anyone heard of anyone doing this with a SeaCraft? I love the hull and here in eastern NC I think it would be the ultimate boat!
Thanks for any inputs you may have
Douglas

ct9amr · #2 11-13-2012, 10:46 PM

Unless you have the know how this will be harder than it sounds.
Engine angle, right trans (ZF or Velvet), exhaust hoses, water pickup, tank locations and strainer.
The tunnel will also need to be wide enough to swing the correct size prop.

I am not sure if the hull can support all that weight in the middle but I know there were some straight inboard seacrafts.

Pickup a cheap shamrock hull if you really want an inboard as they have a protective keel.

Bigshrimpin · #3 11-14-2012, 01:28 PM

I agree . . . find a 23 inboard with the pocket drive. The 20 isn't really an offshore boat and it's not designed to have all that weight. Fun project if you have money to burn and unlimited time. I would imagine your resale value will be 5 cents on the dollar.

gofastsandman · #4 11-14-2012, 03:25 PM

Quote:

Originally Posted by Cheap Thrill

I am in the process of rebuilding a 20' MA, its now stripped to the stringers and am thinking of making it into a straight inboard with a tunnel drive. My brother owns a 20 ' Penn Yan it can go anywere!! It draws 9" of water and he had it 20 miles offshore. Has anyone heard of anyone doing this with a SeaCraft? I love the hull and here in eastern NC I think it would be the ultimate boat!
Thanks for any inputs you may have
Douglas

A comm. guy did one here. No pocket. SB Ford, so yes it can
Be done.

eggsuckindog · #5 11-14-2012, 09:31 PM

guys can't give away inboards on here - why?

agree with above posters

Cheap Thrill · #6 11-14-2012, 10:55 PM

Guys it sounds like a challenge to me!! LOL Now I have a bare hull and no chance of buying another boat (single father) and putting a new outboard on her would be the north end of 13k!! I have all the parts for an inboard and a new 4.3 V6 is less than 5k complete. And if it only worth 5c on the dollar that’s ok I love the hull and not planning on rebuilding to sell! Thanks for all the inputs and I will keep updating on the progress and maybe I'll have my dream boat!!!

Boatboy6 · #7 11-14-2012, 11:47 PM

If it works out this will be one sweet little boat. I've got a special spot in my heart for inboard seacrafts, ill be watching this one!

Bushwacker · #8 11-15-2012, 12:22 AM

They built quite a few 20's with I/O's, and that motor of yours is probably lighter than the 140 MerCruiser commonly used, so it's probably feasible from a weight standpoint, but you'll have to be careful with CG location. Carl Moesly told me the CG on the 20's with 4 cyl. I/O's was actually further forward than it was on the outboards with mid-60's O/B's that were under 300 lbs! It will be even further forward on a straight I/B, so that will be a challenge! Maybe a V-drive would help that. Also not sure where you'd put fuel tanks, but I think they and the batteries would want to be aft of engine. The 23 I/B's with the prop pockets have a reputation for a great ride but are not very fast, maybe because they run with so much hull in the water. The 23 is a much bigger and deeper hull, so better suited to a prop pocket and less sensitive to CG.

I'm guessing you want to leave boat in water all the time, because otherwise an I/O would perform and maneuver better, at the expense of corrosion issues. While the pocketed prop reduces draft and improves the thrust angle, a small high speed prop isn't very efficient and may lose most whatever you'd gain with the shallower drive angle.

Maybe what you really want is a jet drive! It's not efficient either, and don't know how they deal with corrosion issues, but they seem pretty simple and rugged, and might solve most of the other problems related to a pocketed prop! Would also be a short drive train that would help with the CG issue. The USN loved 'em on the river patrol boats in 'Nam! After all, you can build anything if you throw enough time and $ at it! It would definitely be one unique rig!

eggsuckindog · #9 11-15-2012, 01:55 AM

I hate to see a MA tore up and destroyed, as Bush mentioned plenty of cheap Seafari IO's around that need power. They didn't build many of those, so there kinda hard to find.
Because this will never happen, you will have 2 yrs and 2K in materials in before you think about a motor. Then you have to have the know how to try and put the motor in a boat it doesn't belong in.
You can get a pretty decent outboard for 3K or even less and actually get to use it someday.

I have one and don't have a clue where you plan to put the motor - I have 400lbs on the back and a 48 gal tank - another issue, where? - and if full its very noticeable on the scuppers

At some point you will give up and throw it away, as nobody else would want it or they would have built some. They built very few 23's as it was

There is a 20 for sale on here for 2900 that runs I'm pretty sure

BTW We had a 29 Penn Yan at the marina I worked for - couldn't give it away, terrible riding boat and who cares if it goes in 9" of water unless your flats fishing in Fla and then you better be on a trolling motor, hardly something to strive for.

Bushwacker · #10 11-15-2012, 01:19 PM

Interesting to see how Dixon feelings about MA's being torn up are similar to mine regarding Seafari's!

Seriously, if you really want an inboard 20' SeaCraft, this deal on Donald's SF would be MUCH cheaper than building one from scratch! http://www.classicseacraft.com/commu...ad.php?t=24719 The I/O corrosion issues shouldn't be nearly as bad up north as they are here in the barnacle capital of the world!