Author Topic: Butt cat 21ft refurb.. looking for advice (Read 23563 times)

pintocoelho · « **on:** June 10, 2019, 07:16:13 PM »

Hi All,

This is my first post on the forum and having read a number of the topic's it seems there is a massive Butt cat community who can help me with a few questions i have regarding my new project.

I recently purchased a 21Ft Butt cat Hull (one of the old commercial ones.) and will be completely refurbishing the boat - Deck, hull, buoyancy, hatches, top deck, console, etc. The main aim is to maintain the light weight of the original hulls. I will be surf launching and will be looking at travelling with the boat from Durb's to the Kei and up the Zululand coast - So towing is an aspect to consider. I will be replacing the original 85 yammies with new 70HP Suzuki 4-strokes as the boat will be used 2-3 times a week and this will drastically reduce the running costs.

If anyone could provide feedback on the following questions it would be greatly appreciated.

1) The original hulls were built with the foam acting as a structural element to the rigidity of the hull. when stripping the foam, i assume i will need to leave the transom in and install the new stringers and bulkheads in sections. I also assume i will need to install additional stringers and bulkheads to ensure the rigidity is maintained with the new Sondor buoyancy.
2) Stringers & Bulkheads- I am debating whether to install Marine ply or honeycomb? which product is lighter?
3) Sondor vs PU foam - (I know this is a debate on its own) but i am tending toward the Sondor foam option as it is lighter and the noodles can be packed based on hatches etc - my only concern is that there is no fixed platform to screw the deck onto. I think the deck will need to be bonded to the Hull/Gunnels?
4) Top-deck & Console - V-cat in Durban make a modified top-deck which suits the old Hulls - Their price was ridiculous and to be honest, i don't like the look of their top-deck. I like the new Nauti-tech/Butt cat top decks and i think i will be asking them for a new top deck and Console. If anyone knows of an alternate, light and well finished top deck to suit the old hulls?
5) Hull Glassing - I read an article recently stating that the original hull thickness does not meet some maritime ruling. i was planning on installing ONE layer of glass through the entire existing hull to ensure it is sealed off and to help maintain the shape and rigidity - would two layers be recommended? again, this effects the overall weight of the craft.
6) Transom - I have read countless articles regarding the transoms taking water over the back and water running up the decks of the older boats (Mostly due to water in the Hull) - Is there a solution to this other that installing a raised transom (With a false transom and live bait well in my case) and installing extra length outboards? I also need to factor in the additional weight of the new motors (Old 85 Yammies - 116KG's new 70HP Suzi's 156kg)

I look forward to any responses I might receive and will upload progress pictures as this marathon progresses.

Cheers!

pintocoelho · « **Reply #1 on:** June 10, 2019, 07:22:01 PM »

She is really old, and needs a lot of work but it’s a good platform to work from.

The trailer is in fair condition- some minor alterations and a new axle will sort it out

The previous owner painted the hull with a low quality anti-fauling which will need to be cleaned off and prepped before new gel coat

shu vawda · « **Reply #2 on:** June 11, 2019, 09:41:40 AM »

Good Morning.

there is alot of information that you are asking.You are welcome to call me and i will share whatever i can.I have done one previously.the costs can be heavy but worth it at the end of the day.my number is 0722306632.

Shuaib Vawda

pintocoelho · « **Reply #3 on:** June 11, 2019, 07:55:48 PM »

Thank you Shuaib, I did see your refurb post on the forum. It turned out beautifully - congratulations! I can’t wait to see how the 28ft turns out.

I chatted to Ugan at Tri-boating regarding your refurb and he mentioned he had done a fair bit of the work. I have done a lot of work with him on my current boat and his quality and workmanship is generally excellent. I just feel his price he gave me for the work on my butt cat was a little heavy.

I will definitely give you a ring for some advice

Thank you again

Rory mundy · « **Reply #4 on:** June 12, 2019, 12:18:25 PM »

the work that needs to be done that you are talking about doing and replacing your motors, you will be better of buying a good condition boat, there is more work involved in what you want to do than building a new boat from the start

pintocoelho · « **Reply #5 on:** June 18, 2019, 01:11:05 PM »

Hi Rory,

Thanks for the response, we are looking at doing a lot of the stripping and manufacturing in-house.
I have carpenters, boiler makers, glass specialists and spray painters who work within my company so we can split the load when we get a gap in work.
The only items i will be buying new will be the top-deck, consol and fish hatches.
I recently saw the price of new motors and have changed my mind regarding the new 4-stroke option

. Older two strokes will do the trick and servicing is easy!

Progress as follows:

1) Towed the boat to the weighbridge just to check what the starting weight was and it came in at 2450Kg's.
2) We then brought it to the yard and started stripping the deck and found the existing foam completely saturated. What is weird is that even when separated from other foam it still holds the water worse then a sponge - We will weigh the hull again for estimated weight when stripped and then after new foam.
3) stripping foam at the moment - All plywood is completely rotten.

Will keep you posted with progress.

Rory mundy · « **Reply #6 on:** June 18, 2019, 05:29:06 PM »

you have some serious work to do there
i would replace the transoms to take xl motors those old butt always had water on there deck
i will not help to just add one layer of glass if that the route you going do at least a 450 chop 450 woven roven 450 chop
would look at composites for bulk heads and stringers and keels
would use expansion foam to keep the rigidity just do it properly so it fills every noock and cranny
(you can make glass bulk heads and fill with foam aswell)

emjay · « **Reply #7 on:** June 19, 2019, 09:31:30 AM »

Very interested to see how this is going to turn out! Been a dream of mine to restore a boat so I enjoy seeing the process involved. Hopefully it'll be worth it in the end and won't leave your wallet anorexic! Good luck and keep us updated please

shu vawda · « **Reply #8 on:** June 19, 2019, 10:12:21 AM »

Quote from: Rory mundy on June 18, 2019, 05:29:06 PM

you have some serious work to do there
i would replace the transoms to take xl motors those old butt always had water on there deck
i will not help to just add one layer of glass if that the route you going do at least a 450 chop 450 woven roven 450 chop
would look at composites for bulk heads and stringers and keels
would use expansion foam to keep the rigidity just do it properly so it fills every noock and cranny
(you can make glass bulk heads and fill with foam aswell)

I agree with Rory's respone with regards to the additional fibreglassing of the hull.I would like to add that before installing the new glass, NCS has a product called Atprime.this is used for bonding old and new glass and is really effective.its no use installing new glass and it delaminates after a while.

i hope the information that we discussed help and good luck with the build.Keep us posted.

Capt. Hook · « **Reply #9 on:** June 19, 2019, 10:26:21 AM »

I would check that hull for osmosis, I think you have a lot of work to do there.

pintocoelho · « **Reply #10 on:** June 20, 2019, 12:39:39 PM »

@rory, thank you for the response - After chatting to a few guys I have realized that the single layer was a silly thought. I am definitely going to install layers as per your post. - Do you think the layers need to be throughout or could I install 1 layer throughout and 1 layer in the sponsons only? I am going to replace the transom with a marine ply transom but I am keeping it in at the moment to maintain the shape of the hull.

@ Shauib has also convinced me to go with expanding foam and I am going to install the deck first and pour the foam through holes in the deck to ensure it doesn't need to be cut (also his advice - Legend!). Thanks for the advice regarding ATprime - It seems like a must!

I am sending the boat for dustless sandblasting today to remove the existing paint, anti-fauling and clean up bad glassing, and the hull glass to assist with adhesion.

@ Capt. Hook, one of my team members at work has worked on boats his whole life and said the same thing regarding Osmosis. he recommends that we leave the boat in the sun for a few days to dry out and this should clear it up? Is this a truth or does it require some special treatment? and how do you know if it is present/ not?

Thanks all for your advice! Its much appreciated.

Rory mundy · « **Reply #11 on:** June 20, 2019, 02:41:53 PM »

osmosis will show up as bubbles in the gelcoat were the layers of glass have split or in funny colouration just grind out and re layer it up
i would do the whole bottom from a 150mm from the out side of the pontoon going over the tunnel to the other side if you want strength and stiffness
for the bulk heads make a wooden template 150mm thick(A frame) in the depth you need for the hull which you can use to make bulkhead pieces then you use card board as templets as you go along and cut them out, then glass them in place (hope it makes sence will post photos later)
foaming is simple but your hole must be big enough to release pressure or it will pop the deck , smaller compartment have less chance of this happning

pintocoelho · « **Reply #12 on:** July 16, 2019, 11:02:20 AM »

Hi Guys,

a quick update on the work.

1) Boat stripped completely and all holes exposed and patched - three coats of 300G glass & Gelcoat

2) Hull coated with three layers of 300G glass throughout

3) New transom fitted, 7 layers of glass added behind the transom especially in the corners to prevent this from cracking

4) Sawdust and resin compound used in the bottom of the sponsons as thickening to screw the keel into, this also stabilizes each sponson.

5) Stringers and bulkheads installed, excluding the front section (Waiting for the top-deck from Butt-cat to ensure this lines up correctly)

Plumbing will commence today for fuel, electrics and controls.

pintocoelho · « **Reply #13 on:** July 16, 2019, 11:03:27 AM »

More pics

emjay · « **Reply #14 on:** July 16, 2019, 02:14:15 PM »

Awesome! Thanks for the update. Please don't be shy to post more. I'm enjoying this refurb

victorino · « **Reply #15 on:** July 17, 2019, 02:26:59 PM »

What material you using for bulkheads and stringers?

cheers

sardinella · « **Reply #16 on:** July 18, 2019, 10:21:32 AM »

Looking good, no shortcuts, well done

shu vawda · « **Reply #17 on:** July 18, 2019, 05:10:29 PM »

Nice bru.looking good and glad you taking your time with it.Just a question, any reason why you didnt drop the floor level?

pintocoelho · « **Reply #18 on:** July 19, 2019, 08:47:13 AM »

Thanks Bru, ya its coming along slowly.

I chatted to Butt cat who will be supplying the new top deck and they said i shouldn't raise the deck as it throws out the Gunwale height.

They recommended that I raise the transom and put extra long motors, and chamfer the deck down in the wet well behind the new false transom (Also supplied by Butt cat). They also mentioned that the ride changes slightly if the deck is raised.

The false transom has channels either side for the water from the deck to run off, this then ensures the water run off is only from the deck.
We must then install up upstands to separate the motor wells and the scuppers.
Then two drain holes out the well.

Apparently this is their method when refurbishing the older boats.
Len, from Butt cat has been such a help - Always takes our calls, sends pictures and sketch plans for their recent refurbs.

Will keep you posted with developments.

shu vawda · « **Reply #19 on:** July 19, 2019, 10:14:26 AM »

Sorry i think you misunderstood me.I was asking why didnt you lower the deck.from the pictures you attached i noticed in the tunnel area that your stringers are about 100mm above the fibreglass.on my last build we dropped it to get higher gunnels after the floor.

When we did the calculations for the bouyancy, it did not make too much of a difference but made a big difference to the overall height of the gunnels.on these butt cats the gunnels are very low so every bit of extra height you get helps while fishing especially when fighting a fish.

Hope i have explained it well.