View Full Version : Building a Hard Top

02-12-2009, 02:33 PM
Howdy ausfishers,
Just about to commence building a hard top for my 6.5m plate boat. Currently I have a canvas bimini attached to an aluminium frame with rocket launchers attached to the frame. Works well-ish but isnt water prrof, is a little unstable and I just don't like the clears.

So heres my plan:

My brother can aluminium weld with his mig welder (panel beater by trade - has all the gas/parts we need) so he was top of my list to enroll in this little project :D

I've sourced all the parts I need - sheet aluminium (3mm) for top, front and sides, square tubing for framework, lexan/polycarbonate for windows, windscreen extrusions, marine ply for interior skin under roof, various fittings and attachments.

Cost is estimated to come in at around $650 - aluminium approx $300, lexan about $150, window extrusions about $80, ply about $100. Hoipefully will recycle the rocket launcher tubes. Gotta love having mates in the industry!

I'll post pics and progress in case anyone is interested. This will be my first real attempt at modifying a boat. Any suggestions/comments would be greatly appreciated!

Our plan is to head out and pick most of the parts we need to start this weekend! :o:o

02-12-2009, 03:06 PM
Hi Volcano (is that because of something you ate?)

There was a thread on here not long ago from one of the AFs who has made a mould and is turning out ready made bolt on fibreglass hard tops. Not sure of the $s but I have a feeling a professional looking glass hardtop would add more $s to your boat and be cooler too

Do search on here and I'm sure you will find it, or someone else will point you in the right direction.


02-12-2009, 03:07 PM
Good luck with that i am keen to see how you go with it, i will be doing the same in the future but i want it to be able to fold it down similar to the bar crushers canopy's.

02-12-2009, 03:18 PM
@Chimo - not something I ate, just can get a bit fiery :)
Yeah I saw the moulded canopies but I think it would look out of place. I agree they look good, just not quite what I am looking for.

@indy yeah my current bimini folds down. I dont know that I really want my hard top to fold down though. I reckon having it fold down would weaken the structure somewhat and make it more difficult to be able to run wiring up to the top through the ally.

02-12-2009, 03:18 PM
How large will the hard top be 3mm sounds pretty heavy would go to 2.5mm is ample and marine ply underneath very heavy would go celuka. The more weight you add up top in a swell the boat will sway more sitting. Would think by doing this reduce your weight by 30kg.

02-12-2009, 03:42 PM
Hello Volcano,
I did the same exercise 12 months ago.
To my 1985 Sportfish - I'll try and attached before and after photos 4 u .I did an article on the refit in my boat clubs monthly mag. Let me know if u need any advise . My old girl scrubbed up pretty well.

02-12-2009, 03:49 PM
@SNAPPERCOFFIN - well, we considered going with 2.5/2.00mm but the thinner the aluminium the greater the risk of blowout... will investigate a few 2mm sample pieces for welding though. What the hell is celuka? lol

@BeastMaster - that would be outstanding! Your photos look incredible! I hope mine scrubs up that well. I'd love to see your write up if possible!

02-12-2009, 04:04 PM
Celuka is a plastic foam moulded sheet better than ply no need to treat about 1/3 lighter than ply about $30 more a 2400x1200 sheet than ply also fire resistant and bouyant.

02-12-2009, 04:38 PM
Hello Volcano - seems I mastered the photos,
goggle - www.redlandsboatclub.org.au (http://www.redlandsboatclub.org.au)
select the - news letters and down loads section
then select - RBC bulletin - July08 on page 12 of this there is a couple of pages on what I did to the Beast Master.
PS I went clear glass in all the windows , plywood on the ceiling.

02-12-2009, 05:08 PM
Hey Mate,

Sounds great. You sure you did the material estimates right though. $300 for the ally for a 6.5 T Top seems light on to me unless you have a special supplier. Cut 3mm runs for about $90 sq meter. Also have you considered TIG instead, MIG'ed ally looks ordinary in my view. TIG would also stich that 2mm roof easy as as well and look sweet. I agree, 3mm would be heavy. What wall thickness you using on the tube?

I've just finished a live bait tank / bait board combo and that cost me more than $300 in ally, although I did get some cuts and folds, so if you can build a T Top for that you should be happy.

Not being critical or trying to be smart mate but I play with Ally myself. Good luck. Post some pics when your done.

02-12-2009, 09:53 PM
i agree tig would look far better in presentation.

02-12-2009, 10:37 PM
@MackeralMan - yeah I have a close family friend in the industry. Wholesale cost prices. Looks like 2mm is going to be the go - welding beads look great and its much lighter.

@DTCoCo - Given I don't own a [TIG] welder and my bro's welder is a MIG welder I'm not about to demand he buys/hires a tig. His mig welds look outstanding. MIG it is.

03-04-2010, 07:41 AM
Any progress pics, please?


gr hilly
03-04-2010, 09:20 AM
beast master you have done a fantastic job there mate well done i would copy that but i only have a 4.2 little baby,yours is one of the best ive seen.