Formula 15 Renovation

[ducky]

This just might be the quickest 445f/f15 diy rebuild known to man

Depends how long the tank build takes once I’m ready to get it measured and made. Can see that really shitting me off haha.

Been rough balancing a full time job. Wiring up the new berleypro/tasline venture along with doing this. But it helps when you work 24 hours straight to fit it in every weekend. Haha

[VooDoo]

This just might be the quickest 445f/f15 diy rebuild known to man

And our man is doing it solo as well

Top Notch Effort Ducky .. you're on the home straight now!!!

[4liters]

Well transom is fully tabbed in. Time to focus attention on the stringers so I can start the grind out of the boat and really kick this project into gear.

First step was to get a bit of timber same width as the stringers. Screw it into place using the old stringers and then measure down to work out the template.

Did that. Trimmed it out and it went in like a finger in Dougie’s bum. Zero resistance whatsoever.

Took the punt on the other side just mirror imaging it and it worked a treat.

The put my efforts into trimming out the front bulkhead. Decided to trim it at my seat height. From here I’ll actually run the seat timber the whole way under the anchor well which will give me something to bolt the anchor to without having visible bolts. As well as provided extra storage under that front seat.

Next step. Cut the stringers and remainder of the floor out and fully grind the hull out.

Like cut out passing a couta down a hallway?

[ducky]

This just might be the quickest 445f/f15 diy rebuild known to man

And our man is doing it solo as well

Top Notch Effort Ducky .. you're on the home straight now!!!

I dunno mate. Still lots to do. I reckon I’m at about the 1000m mark of the Melbourne cup. But it’s progress

[Gultch78]

Are you foam filling
Are you concerned about hard spots
Are your box stringers thick enough to limit longitudinal flexing
Have you thought about tabbing inside of stringers
Have you considered centre of gravity in regards to decreasing weight below water line

[Bugatti]

Have you considered centre of gravity in regards to decreasing weight below water line

Not sure with ducky's re-build but with most re-builds (mine included some years back) you end up inadvertently adding weight just by glassing over already glassed areas and so forth.

I'd say, to be confirmed or denounced by ducky, that the hollow Stringers would just offset any weight gained through other parts of the re-build.

Cheers, Bugs , , , , had some weight gain and in need of a re-build himself

[ducky]

Are you foam filling
Are you concerned about hard spots
Are your box stringers thick enough to limit longitudinal flexing
Have you thought about tabbing inside of stringers
Have you considered centre of gravity in regards to decreasing weight below water line

1. Foam filling stringers only.

2. Probably a case of unconscious incompetence around hard spots. Please explain?

3. Box stringers aren’t thick enough yet to limit flex but they’ll be heavily glassed when laying up. Plus I’m going to run a 19mm ply support along each side from console to transom to give knees as well as providing screw mounts for all my crap without penetrating the box stringer

4. Can’t see a way to tab inside of box stringer. They are quite small. But as previously mentioned exterior layup will be very heavy.

5. Can’t see me reducing below waterline weight. Adding 1500gsm to the entire hull pre putting in stringers etc and then adding in below floors fuel etc. will be heavier down there compared to before.

[Gultch78]

Are you foam filling
Are you concerned about hard spots
Are your box stringers thick enough to limit longitudinal flexing
Have you thought about tabbing inside of stringers
Have you considered centre of gravity in regards to decreasing weight below water line

1. Foam filling stringers only.

2. Probably a case of unconscious incompetence around hard spots. Please explain?

3. Box stringers aren’t thick enough yet to limit flex but they’ll be heavily glassed when laying up. Plus I’m going to run a 19mm ply support along each side from console to transom to give knees as well as providing screw mounts for all my crap without penetrating the box stringer

4. Can’t see a way to tab inside of box stringer. They are quite small. But as previously mentioned exterior layup will be very heavy.

5. Can’t see me reducing below waterline weight. Adding 1500gsm to the entire hull pre putting in stringers etc and then adding in below floors fuel etc. will be heavier down there compared to before.

Hard spots occur when putting in stringers or any vertical knee against the hull with insufficient tabbing to spread out the blows from pounding waves (picture karate chopping the hull in one spot repeatedly now picture your hand from tip of pinky finger to base of palm as skinny knife edge of your stringer)
Now if stringer is roughly 5mm then tabbing is 5mm but your stringer is only tabbed on one side then your not really spreading the load you have just stuck a 5mm right angle on hull
I might have to draw a diagram to explain if you're not following I have attached pic of my fibreglass stringers after foam filling the slots were big enough to get arm inside and tab inside of stringers as well as outside so force is spread out through tabbing on both sides

[ducky]

Ah yes I follow now.

With my stringer being 180mm wide and effectively tabbed in both sides albeit with distance between is this still likely to pose a problem?

I can’t see any easy way to tab the inside without cutting a lot of the top of the stringer out. But I’ll explore this option as I certainly don’t want to screw it up and re laying the glass is the easy bit.

As an aside I spent about 4 hours with the 180mm grinder tonight and have majority of the hull ground out and old stringers remove. Need another 3 hours or so then some detailed work around the anchor well and she will be ready for hull layup

[ducky]

So that 3 hours of grinding was a load of crap.

Spent 5 hours on the grinder today. Grinding out old bog from the stringers was slow going even with the zek disk.

But have gotten everything out. Ground back all the delamination etc. have filled in the strakes with bog tonight to complete final grind out tomorrow morning to get rid of all the last remnants of flowcoat and anything else prior to beginning the hull layup.

Chose to fill the strakes to make laying up the hull much easier as well as the tabbing in of the stringers as few areas had some nasty angles to contend with. Should get a better result this way.