1973 Formula Thunderbird Tri Hull Restoration

[RobertHope]

Hey all,

Managed to come across this old tri hull for free!! Picked it up and started the tear down. Seemed to be in reasonable shape. Managed to get as far as I can without lifting the cap off, amazing whats achievable with a hammer and chisel!! Small moment of sheer joy when it seemed the stringers were going to be ok, only after closer inspection to find them rotted out!! Dammit! Got some more muscle power and more tools tomorrow so will see how we go. Still need to lift the cap, front deck, tear out the rest of the foam and check the transom... haven't been able to see it yet so fingers crossed! Will keep posting pictures as the project progresses, if they haven't shown up here or theres an issue tell me as computers really aren't my thing!! Apologies for the crap quality, the camera on the phone is all messed up!! Let me know what you think in any case!! Till next time...

Oh, and if anyone can tell me a little more about this year and model that would be sweet, seems theres no pictures or info anywhere!!

 

[RobertHope]

Re: 1973 Formula Thunderbird Tri Hull Restoration

Finally managed to get the transom free from the cap!! What an almighty pain in the arse!!! a few blocks of wood/giant chisel/truck jack later and boom! Now on to the walk through section of the bow, let the fun begin.... again!

 

[RobertHope]

Re: 1973 Formula Thunderbird Tri Hull Restoration

WooHoo!! The cap is now completely free from the hull! What an absolute mission! Managed to finally pry the walkthrough section away from the old bow deck section, was sealed completely shut! Its still in place sitting on top of the hull on wooden supports, next job is to find somewhere to keep it until the time comes to put her back together! Best tool we used was the truck jack, loosened the seal around the edges of the walkthrough section then with wooden supports raised the truck jack to pry the remaining bond free from the hull!! Trying to upload the photos from my phone but having some issues, will get them up tonight/tomorrow morning. Cant wait to get through the rest of the bow section and start grinding, feel like the first checkpoint has been reached!!

 

[Woodonglass]

Re: 1973 Formula Thunderbird Tri Hull Restoration

Hopefully you have taken a LOT of measurements of the interior of the hull to ensure you can put her back the way she was!!!

 

[RobertHope]

Re: 1973 Formula Thunderbird Tri Hull Restoration

Certainly have, still yet to remove stringers/transom/old fiberglass so all is still in place apart from one bulkhead which has been measured! Hoping to get the photos up tomorrow morning, have some help coming tomorrow evening to lift the cap and find somewhere to put it until the rebuild Hoping to get the whole front section of the old deck up to use as a template too as for the moment its still intact!! Transom is looking old and rotted but hoping to get a template from that too Will let you all know tomorrow, fingers crossed!!

 

[RobertHope]

Re: 1973 Formula Thunderbird Tri Hull Restoration

Here are some more pictures, as you can see progress has been slow! Where the cap joined the transom and where the walkthrough section is to the bow, both these spots were solidly bonded to the bow section of the old deck and the transom. Took two of us a few days to figure out the best way of getting them free. My apologies for the quality of the pictures again as the camera on my phone is still up the creek! After seeing a vid on youtube we tried using the truck jack with wooden supports underneath and a wooden block on the pressure point to slowly lift the bond free. After a few hours of weakening the seal as much as possible we put the jack in place and lifted, after much popping and sizzling (sounded like some top quality bacon in a pan!) we got both areas to pop free with a satisfying bang! No damage to the cap and good to go!! We have some more guys coming this eve to lift the cap out and get it safely stored so we can crack on with the measurements and rest of the tear down. Still need to get the front section of foam out, and measure measure measure!

 

[RobertHope]

Re: 1973 Formula Thunderbird Tri Hull Restoration

Some more pictures

 

[glnbnz]

Re: 1973 Formula Thunderbird Tri Hull Restoration

Signing on to watch the fun!! Like the old Tri-Hulls!!

 

[RobertHope]

Re: 1973 Formula Thunderbird Tri Hull Restoration

Nice! Its slow progress so far but will be trying to pick up the pace over the next month or so! Love your Tri-Hull! We too are thinking of 85hp, she is 15', any ideas on speed, I know it depends on the hull of course but wondering what the ball park figure might be. We've seen a real nice 1974 merc, rebuilt and looking brand new with running videos etc, it looks to be the exact same model/year as in the original formula thunderbird brochure from '73. This is all considering its still available when we get to that point! Long ways to go yet!

 

[glnbnz]

Re: 1973 Formula Thunderbird Tri Hull Restoration

My 85hp with the prop it has on it runs about 30-35 WOT. I need to get my Tach working and could use a new prop. My boat is a 16 footer and it weighs in at about 1000 pounds dry. I am not really too sure how fast it should be able to go, but I it cruises fast enough for me and pops out of the hole nice enough to pull a skier right up

 

[RobertHope]

Re: 1973 Formula Thunderbird Tri Hull Restoration

Hey Glen, thanks for the info!! Looking forward to getting to that stage, will let you know how it goes when we do!

 

[RobertHope]

Re: 1973 Formula Thunderbird Tri Hull Restoration

Ok, so this is the last time I use my phone to email photos to myself, just takes terrible pictures and has serious issues emailing them to myself!! It doesn't like it at all!! Will be using the proper camera after this bunch. Just thought I would show what we got done yesterday, managed to get a picture of the stuff that was holding the walkthrough section to the bow section of the deck. Stuff was like glass and really brittle, solid as a rock too!! finally managed to get the front deck section up and all the foam out, center stringer looked like it had buckled at one point!! Scary thought!! Off to buy the correct PPE tomorrow and start with the grinder. Managed to get the front deck section out as a whole so have a good template with both front and rear. Any suggestions on the next step from here? De-skin the transom or grind the lips back. I have more photos of both lips and the transom which will be going up as soon as my phone decides it feels like sending them through!!!!

 

[RobertHope]

Re: 1973 Formula Thunderbird Tri Hull Restoration

Here's the ones of one lip and one of the transom, will get the other lip in when the phone agrees with me!!

 

[RobertHope]

Re: 1973 Formula Thunderbird Tri Hull Restoration

The next batch will all be the right way up too... apologies for the neck crankers!!

 

[RobertHope]

Re: 1973 Formula Thunderbird Tri Hull Restoration

the other lip

 

[RobertHope]

Re: 1973 Formula Thunderbird Tri Hull Restoration

Quick question, is it possible to use the skin of the transom as a template if it is accurately cut??

 

[Woodonglass]

Re: 1973 Formula Thunderbird Tri Hull Restoration

Yep, but... You don't have to be real accurate. In fact you don't want a real snug fit. 1/2" all the way around is good enuf. You need the space to fillet and seal the edges.

 

[RobertHope]

Re: 1973 Formula Thunderbird Tri Hull Restoration

Transom & stringers are out, managed to get some great templates for all of them!! Started on the grinding today, ohhh joy!! Painters suit does absolutely nothing!! The itch!! Ohhh the itch!! long sleeves are currently an impossibility!!

 

[RobertHope]

Re: 1973 Formula Thunderbird Tri Hull Restoration

Just wanted to make sure we're doing this right and not grinding too much! The fiberglass is real old and nasty and pretty much yellowish all the way to the actual hull, if you can see from the picture we're trying to get rid of all of it up to where the deck meets the sides of the hull, then we're going to grind about 10" above, but only one or two layers for the tabbing in of the hull when we get round to that point. At the moment the hull has three layers of really heavy duty fiberglass which we're stripping away, following the lines of the original edge of the deck! Any advice would be really appreciated!! Many thanks as always!

 

[RobertHope]

Re: 1973 Formula Thunderbird Tri Hull Restoration

Hi all, apologies for not having posted recently, just trying to trudge through the grinding, should get it finished today!! Setting up the order for fiberglassing from Fiberglass supply depot, after some reading and research seems to be the best value! For a 15ft stringer/transom/deck (as seen in the pictures) is there anything missing from the essentials in this list, apart from rollers and mixing jugs? And for the chopped fibers here, https://fiberglasssupplydepot.com/1-4-Chopped-Strand.html how many pounds do i need? Think i'm right in saying they come in 1lb bags?! Here is the list so far

Premium Polyester Resin - 5 gallons with hardner

FIBERGLASS MATT 1.5 OUNCE - 15 yds

FIBERGLASS BIAXLE 1708 - 10 yds

CABOSIL - 1 gallon

1/4" Chopped Strand - I have put 5lbs but that is a complete guess??

As far as the glassing is concerned i think i have my bases covered here but any input would be greatly appreciated before the wallet gets it first big surprise :facepalm:!! Many thanks as always for any input