1976 Seacraft MA

Duckin20 · #1 04-20-2015, 03:08 PM

Hello everyone, I am new to the forum, I am from Palm beach florida and Currently have been restoring my first Seacraft, I have restored a few 20ft Mako's in the past and I received the opportunity to go for a ride on a 20ft Seacraft and the Mako was sold. I have already redone the deck, replaced the gas tank and replaced my transom, However, I did not enclose my Transom as I am an avid diver and wanted to use the space for easy access into the boat. I have a single Armstrong bracket and this weekend i will be rigging, I will either be putting a 2001 250ox66 on or a 2003 evinrude 175(which I am leaning towards)

cdavisdb · #2 04-20-2015, 04:07 PM

Welcome to CSC. You free diving or tanking?

Any way to add a floatation chamber under the bracket? The 225 is pretty heavy(not sure about the weight of the 175) and either is way more power than you need, even loaded to the max with divers and gear . The weight in the stern, especially on a bracket, will make it hard to plane slow, even with tabs. Divers climbing over the stern with that set up will make it very tail heavy. You would need to be careful to put a lot of weight forward, ice boxes, tanks, etc.

Duckin20 · #3 04-20-2015, 04:17 PM

Thanks for the Words of wisdom, I will be free diving majorly but tanking in the keys during the summer, all of my tank holders are in the bow, along with the batteries and storage, the 175 weighs aprx 410lbs, hoping that it will be ok? I do have a floatation system i will be working on in the bracket. originally i was going to use a 115 etec, but have been pushed away from it.

gofastsandman · #4 04-20-2015, 07:16 PM

Welcome to the neighborhood Duckin. Did you move the tank forward?
Light and balanced is what these hulls love. For the VDH to work properly, the angle of attack and CG are kinda important. I thought a 115 etec might be a poor choice, but after riding on CJ it is just perfect weight wise. No speed demon, but just perfectly balanced.

I have a carb`d 150 rude on the transom at 365#s and she is just self bailing at rest.
Move that back and everything changes.

The VDH is almost like air suspension, change the angles and the stall horn goes off.

Duckin20 · #5 04-20-2015, 08:39 PM

Thanks for the info, I designed the tank structure to be at a positive cg currently according to my calcs I should be ^25% in the bow. I will not know until everything is rigged, I really want a 150 2stroke, but now I'm limiting my options

gofastsandman · #6 04-20-2015, 09:34 PM

Quote:

Originally Posted by Duckin20

Thanks for the info, I designed the tank structure to be at a positive cg currently according to my calcs I should be ^25% in the bow. I will not know until everything is rigged, I really want a 150 2stroke, but now I'm limiting my options

Nice thinking.

Bushwacker · #7 04-20-2015, 11:54 PM

Welcome aboard Duckin! Good to see another SeaCraft addict in the local area! Trust me, lighter is better on the 20' hulls! That 2003 motor would have been made by BRP, and even it it's a Ficht, would be a much higher quality than a late 90's OMC motor. (This is first hand info from an engineering colleague of mine that was Chief Engineer at the Test Center in Stuart!)

I'm continually amazed by folks that think a 20' boat needs a 500 lb/250 hp motor! Carl Moesly designed the 19/20 ft. hulls in the mid-60's for the biggest outboard motors available at the time, i.e., the I-6 Merc and V-4 OMC, both of which weighed 300 lbs or less and put out something like 100-110 hp. That means the VDH hulls are designed to perform best with light and relatively low powered motors. He included a lot of subtle details in the design to achieve that, like a wedge built into the outer panels for low speed lift and rocker in the inner panels to allow bow lift at high speed. They're much more efficient and ride much better than the modern 8' wide 20' boats that are designed for 500 lb 4-stroke motors hanging on the transom! I was fortunate to have run my boat for over 30 years with a "spec" 300 lb/~100 hp motor, including a half dozen trips to the Abaco's with very heavy loads including lots of dive gear. I was frankly amazed at it's performance compared to newer larger boats with a lot more power. Although I had trouble staying up with the newer V-6 motors in flat calm conditions, once we got into the 2' square waves on the Bahama bank, my little 20' Seafari, with lots of gear loaded in the cabin, could easily stay up with the bigger boats in that nasty chop! When I added a bracket and repowered with a 427 lb motor in 2006, I had to do lots of tweaks (4B stern lifting prop and a Doelfin) to get back to the 12 mph planing speed and soft ride that I had with the original "as-designed" configuration! You might want to check out my post on the Pros & Cons of brackets in the Repairs/Mods section for more info! Denny

Duckin20 · #8 04-21-2015, 07:06 AM

Wow glad too see there's a lot more seacrafts in the local area! Thanks bushwaker, it's not that I need a 200-250 it is just was available, I can also get my hands on a 125merc and like I said that 115 etec, do you think I should go with one of those no matter what? I'm not really a go fast boater anymore, really just looking to get a smooth ride with 1-2guys and a boat full of tanks and gear, maybe hoping for the 22-25knts range? Thanks so much for the advice.

Bushwacker · #9 04-21-2015, 12:04 PM

Quote:

Originally Posted by Duckin20

. . . I can also get my hands on a 125merc and like I said that 115 etec, do you think I should go with one of those no matter what? . . . .

Either would be plenty of power for what you want to do. Don't know if the merc would be lighter, but there is a great E-TEC forum that's similar in quality to this CSC forum and supported by some very good factory trained techs that would be a big factor in my decision!

Bigshrimpin · #10 04-22-2015, 09:50 PM

Totally agree with Bushwacker on the 20 . . . Those large heavy motors (3.0L+ 250hp) will destroy a stock 20 seacraft in short order unless it's been beefed up and overbuilt. IMO the 20 seacraft shines at 18 - 22mph in rough water and a 27 - 30 cruise in calm water / light chop. With a light motor and good weight distribution the hull will dance and surf. With a heavy 500+lb beast the hull will drag azz around doing wheelies and never ride right. You might be able to hit 55+ WOT but it won't hold together very long . . . Just my opinion.

I had to stuff the bow more than a few times at high speed to figure this out.