10' GW Invader Help

[Malidrag]

First let me say hello. I am new here to the site and pretty much to setting up boats. I am fimiliar with boats and have 2 but I have bought them and never changed a thing on thim for set-up cause they work. I recently have purchased a 10" GW invader that I would like to set-up with a 50hp outboard. My main goal with this boat is to put it in the 50mph range. I have done some reserch but really cant ge much on the set-up. I have seen pics of 50's of bigger hanging off the back but no info so I figured I would ask for help so here I am.

I have started by ripping out the floors in hope of making the boat as strong as possible. I havent glued anything down yet becasue im not sure if I need more support so I am asking you guys and gals for help if you can. I will post pics of where I am at.

What I want to do and what I think I know is the following.. 50hp with power trim. not sure if I should go with merc 4 cyl 50 or evinrude 2 cyl 50??? Thinking I need to use a short shaft. Figure battery in front of me in center for weight. And figure I need the hull strong.. Pretty much thats all I know

Any help would be apreciated.. Thanks in advance

[jacklake2003]

Cool project! I would stick with a 2 cylinder due to weight. It looks like a short-shaft may be the way to go. 50mph may be a little tricky, but I'm sure it's possible. Good luck and keep us posted.

[specboatops]

They use to run em with 50"s and 65's back in the day. Do a search on here there was a member who was making these again calling it a Supervader....making the bottom much better than the original. Good Luck. Keep us posted !


Chris

[stvhelm]

i have one of those if your interested. $250 no papers. needs work. just hull nothing else. I was gonna put a shorty 3cyl merc 70 on it. we found something else so it just sits here doing nothing.

[Malidrag]

If I measure the transom it is pretty much 15" so the short shaft should work. I was leaning more towards the 50hp 2 cylinder also. Figure keep it as light as possible and I think it will look correct hanging off the back of it also.

I have heard of people who have installed trim tabs and some that have installed a fin under the keel in the back. Havent heard anything else like why and how does it handle like that. All the posts I have seen are almost 2 years old.

I would like to glass down my floors this weekend. Do you think my frame work will be enough? I havent seen any pics of the inside of these boats completed so I dont know. I will be putting 1/4" ply over framework after it is all glassed down..

Thanks again

[activator22]

IMHO, the framework looks overkill. Hard to tell, but it looks like you are using pressure treated wood ? If you are, do a search thru the forums, there can be issues glassing it down. It's more common to use 1/2 or 3/4" plywood for the stringers (exterior grade is fine as long as it's sealed)

[RONNIE]

those boats have plywood coring and are usually wet and very heavy. Before you glass anything in you should do a little more investgation into the coring and see if its all wet. redoing it would get quite a bit of wieght out.

[cvsteve]

I have a GW invader with a 1967 Merc 500ss short shaft that would run between 45-50 mph with a 13 pitch merc 2 blade. It would take a little bit to get up on top but once their it was fun to drive. It does a bit of porpoising at midrange but when you give it full throttle, it would twist the stern loose a bit then take off. I want to find a 15 pitch as I think that it would drop my rpm's a bit. I have a 17 pitch nos 2 blade bronze prop but I feel it wouldn't get my butt up on plane! I really wish it had a fin on the bottom as I feel it would make a little more stable(especially in turning). I also have the cable and pulley steering which I have to monitor closely. I also think a kill switch is in order! Mine doesn't have power trim and the merc is bolted right to the transom. Driving a small boat like that is a blast and sometimes unnerving but you can't beat the excitement.

[Malidrag]

IMHO, the framework looks overkill. Hard to tell, but it looks like you are using pressure treated wood ? If you are, do a search thru the forums, there can be issues glassing it down. It's more common to use 1/2 or 3/4" plywood for the stringers (exterior grade is fine as long as it's sealed)

Yup its Pressure treated and now after doing a search its all coming out..Will make a good pattern to follow. Thanks for the heads up. I did the frame work that way because I want everything that I need to mount in the boat screwed down into the ply and stringers so I figure build it with wider material so I will have a better chance not missing.

From what is in there now for plywood its very dry and solid. Seems to have been somewhat taken care of over the years.. Transom is solid and no signs of damage.

[Malidrag]

I have a GW invader with a 1967 Merc 500ss short shaft that would run between 45-50 mph with a 13 pitch merc 2 blade. It would take a little bit to get up on top but once their it was fun to drive. It does a bit of porpoising at midrange but when you give it full throttle, it would twist the stern loose a bit then take off. I want to find a 15 pitch as I think that it would drop my rpm's a bit. I have a 17 pitch nos 2 blade bronze prop but I feel it wouldn't get my butt up on plane! I really wish it had a fin on the bottom as I feel it would make a little more stable(especially in turning). I also have the cable and pulley steering which I have to monitor closely. I also think a kill switch is in order! Mine doesn't have power trim and the merc is bolted right to the transom. Driving a small boat like that is a blast and sometimes unnerving but you can't beat the excitement.

I have heard it takes a bit to get on plane but once there its a blast. Im hoping with power trim it will get on plane faster and be able to dial it in better on top end when needed. I have the cable and pulley system now. What do you mean you need to keep an eye on it? Is that something I can improve?

Thanks again for all the help

[cvsteve]

Keep an eye on the anchor bolts on the pulleys since on an older GW they are mounted into wood blocks that are glassed in place. They deteriorate over time and if I haven't used the boat for any length of time, I recheck those points. Ideally, I'd like to go to a rack system to have some peace of mind! If you find a Merc 50 4cyl., that would make a killer combo! Good luck and keep asking questions.

[activator22]

Yup its Pressure treated and now after doing a search its all coming out..Will make a good pattern to follow. Thanks for the heads up. I did the frame work that way because I want everything that I need to mount in the boat screwed down into the ply and stringers so I figure build it with wider material so I will have a better chance not missing.

From what is in there now for plywood its very dry and solid. Seems to have been somewhat taken care of over the years.. Transom is solid and no signs of damage.

As long as you mark the centerline of the stringer/frames on the floor, should have no problem fastening down to a 3/4" piece. But as an alternative to a bunch of screws, look into using 3M 5200, it's possible to bond the whole floor down with that and no screws and then just tab the edges (perimiter) of the floor to the hull with 'glass

[Malidrag]

I was thinking of bonding it down with the 5200. Wasnt sure if it would be strong enough all by itself so I was going to do both. If I can get away from using the screws that would be nice.

I was planning after all the stringers were glassed down and the ply is layed on top to go around the perimiter with a 6" fiblerglass cloth tape and join the floor to the sides of the hull for strengh.

[99fxst99]

A friend had one in the 70s with a 15" 50hp Johnson. Ran about 50 with a 2 blade 23" aluminum OMC prop. vStruggled to get up, but once it got going it was a blast. The prop hooked up about 40-45 and it felt like it shifted gears! I personally would keep the cable steering. You can adjust the slop out and it is much easier/more fun to drive. Buit as cvsteve said, keep an eye on the anchor points. use backing plates where possible.

[tj309]

I had one too back in the day. The previous owner had a Merc 50 4 cyl on it and it rocked. I got the boat and put a Merc 35 4 cyl and could get 38 out of it with no driving issues. I really wanted to put a Merc 65 on it but never got that far. That boat was like my 1st car. I had an old college buddy stay at my lake cabin a couple of months ago and after we took the Venom out he said "this boat is like your old GW Invader on steroids". I did some interior glass work on the floor - I removed the plywood between the stringers and lowered the floor a bit. What a great boat. You must use a 15" shaft motor. Back in the 70's a standard shaft motor was 15" and long shaft was 20". Now the standard is 20" and unless you are buying a small fishing motor you cannot get a motor of decent size in a 15" shaft. That really sucks because the Venom is really set up for a 15" as it is a racing hull.

25"? XL
30"? XXL

How times have changed.