72 SF20: Refurb / Repower Question

[mjc]

Greetings everyone,

I’ve lurked this site for YEARS as I grew up in South Florida in the original Seacraft, Bertram, Mako, Aquasport era and have always wanted a Seacraft.

Finally pulled the trigger: a 1972 SF 20 CC that has sat idle for the last 5-6 years.

My goal is to restore as near to original as possible.
The condition is not bad (all things considered) but the transom was wet and had rot so we’ve started on that project.

Repair is being done from the outside utilizing Coosa for the core and polyester/vinylester for the layup, and will raise height to 25.5” (+5”). (I will post photos when I figure out how).

My question concerns engine / weight. I would like to use a new generation engine but the weight (and distribution) concern me.

Here’s the plan for weight reduction and relocation:
1. Move battery and wooden box forward to console (-50lbs).
2. Replace marine ply with coosa (-39 lbs).
3. Close off stern live well to increase buoyancy: based on size and depth underwater at rest (-50lbs).

The original engine was a 125 hp Johnson PTT (264lbs) and a 9.5 hp Johnson kicker (60 lbs) which put 324 lbs on the transom). In 1989 the engine was replaced with a 140 hp Johnson V4 looper (340 lbs); don’t know whether the kicker came off but the bracket was still there.

So…………… do you think that I could do 400lbs engine weight without upsetting the distribution and / or buoyancy?

(also posted in Repair/Mod forum)

[McGillicuddy]

Originally Posted by mjc

Greetings everyone,

I’ve lurked this site for YEARS as I grew up in South Florida in the original Seacraft, Bertram, Mako, Aquasport era and have always wanted a Seacraft.

Finally pulled the trigger: a 1972 SF 20 CC that has sat idle for the last 5-6 years.

My goal is to restore as near to original as possible.
The condition is not bad (all things considered) but the transom was wet and had rot so we’ve started on that project.

Repair is being done from the outside utilizing Coosa for the core and polyester/vinylester for the layup, and will raise height to 25.5” (+5”). (I will post photos when I figure out how).

My question concerns engine / weight. I would like to use a new generation engine but the weight (and distribution) concern me.

Here’s the plan for weight reduction and relocation:
1. Move battery and wooden box forward to console (-50lbs).
2. Replace marine ply with coosa (-39 lbs).
3. Close off stern live well to increase buoyancy: based on size and depth underwater at rest (-50lbs).

The original engine was a 125 hp Johnson PTT (264lbs) and a 9.5 hp Johnson kicker (60 lbs) which put 324 lbs on the transom). In 1989 the engine was replaced with a 140 hp Johnson V4 looper (340 lbs); don’t know whether the kicker came off but the bracket was still there.

So…………… do you think that I could do 400lbs engine weight without upsetting the distribution and / or buoyancy?

(also posted in Repair/Mod forum)

There are a lot of guys running 400 lb motors on a 20. You're already considering the balance, so keep an eye on that as you go and you'll be fine.