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View Full Version : Advice Needed Please - DeHavilland Trojan(pics)



crankit
26-12-2006, 10:10 PM
I've inherited a boat from my father who passed away, I'm 21 so I know little and have heaps to learn. I've been doing research and also bought the Seloc 68-93 Penta manual.

Over the past few months I’ve saved up a few thousand to spend on the boat. I'm not happy with it as it currently is because of my dads bush mechanic style of fixing things. So i want to make it right, make it last, so I can enjoy trouble free trips on the reef.

We took it out 2 years ago when dad was alive, I took it out once again after he died, bout a year ago. About once or twice a month I hook up the hose to it and give the engine a run till the thermostat opens up.
So atm it still works.

Heres some pics, and what I’d like to do. I'd be grateful for anyone’s opinions and criticisms.

http://img403.imageshack.us/img403/6310/pict000cho5.jpg

So here is the transom, as you can see he’s made up this thru hull exhaust system. His Idea was to try and muffle the sound, but it doesn’t work all that great as it’s still noisy and I get the feeling it might give to much back pressure. So I’d like to redirect it thru the drive.

Another bout the drive is he put this humongous prop on it, because it has the 4cyl ratios

The transom has also got corrosion from old holes from past exhaust setups, and also a pod for the spare outboard on the left that was suppose to double as a fuel tank. Except it leaks and also makes it impossible to trim the boat with the tabs.

So I’m thinking of taking the drive out and taking the boat to an alloy engineering place here to get the transom with that pod/tank cut out, and a new transom put in, so I can start things from scratch with a clean transom.

when that’s done I’d like to put a 280 lower with proper v8 ratios and mate that up with the old 307 and 270 upper, with the proper manifolds, risers and y pipe. I’ll then have the exhaust going thru the drive.

I also want to have one of those adjustable outboard brackets so I can have the trim tabs under it on the transom, and so the outboard will sit out of the water during cruise.

So is this the right way to go about it, or are there other alternatives.

http://img172.imageshack.us/img172/1883/pict0010gc6.jpg


This is the 307.

The fans there for air to circulate,(I don’t mind this idea) Any comments

It’s also raw water cooling, and I’ve been told this is fine as long as I flush it out after salt use.

He also made his own exhaust risers out of copper piping (I’m worried about these, and I know it be very hard to hook them up to the drive, which is why he never did it.

The manifolds are something I’ve never seen anywhere, and I know I couldn’t hook up Volvo risers with the y pipe for thu-drive exhaust. So I’m thinking of buying the Osco Volvo replacement–

manifolds -http://www.marinedirect.com.au/catalogue/category158/category1/category221/product55605

and risers -http://www.marinedirect.com.au/catalogue/category158/category1/category221/product55606,

And a y pipe if I can find one. Hopefully that quiets things down.

I’m also going to rewire everything according to the seloc manual, just so I know whats going where.


http://img142.imageshack.us/img142/3605/pict0003fx5.jpg
Thats the pod I was talking about

And Here is the boat in question. It’s a 21 ft 1970’s DeHavilland Trojan. The rest of the hull is in fairly good condition though my dads old mate is gonna repaint it and i'll probably also replace the flotation. The only thing i wont do is have a massive outbourd instead of the sterndrive. mostly becuase of my familiarity with car engines.
http://img401.imageshack.us/img401/4518/pict0014fr6.jpg

I welcome any opinions, criticisms or ideas.
Thanks..





- [smiley=cowboy.gif] [smiley=builder.gif] [smiley=builder.gif]

Chimo
26-12-2006, 10:31 PM
Hi Crankit

All power to your late Dad. He obviously had a few clues and got things done. Nothing wrong with bush mechanicing. But that said............

This looks lke the sort of set up that would be great if you built it and fully understood it but if not and you want to venture far and wide would some other alternatives bear considering?

Like considering an outboard motor to replace the current setup. You were talking about altering the transom and the pods so by fitting an OB you would probably gain space , reduce the noise make the unit a lot less dangerous from fire and with the auxillary still have a backup motor to get home if need be.

Maybe a bit radical but perhaps do the sums with new or second hand outboards. There might even be some Ausfishers who could point you in the right direction with the transom / pod revision

Anyhoo that the quick thought for now, now doubt there will be a lot of options floated for this one.

Good luck with it, which ever way you go.

Cheers

Chimo

BilgeBoy
26-12-2006, 11:08 PM
Hi Crankit

Wow...nothing like inherhiting your old mans toy...think of the joy it brought him just working all that out and creating all that stuff...and now look at you!!!

I am a car mechanic by trade and hate outboards....but I still have one on the back of my boat!! Sure would solve a lot of probs! But if you are stuck on the inboard no probs...just need to get it done. try takin it down to your local boat shop and havin a yak with them. That or search out the speedboat boys who race...you can get stacks of ideas talkin to these guys!!

Good luck with it and enjoy!

BilgeBoy

crankit
27-12-2006, 02:16 AM
Thanks for the quick replies.
Chimo the outboards are something I will check out as another option, i can see outboards being a great idea for alot of people. But i've kinda grown up with sterndrives and old cars and with my limited experiance owning a boat I still feel safer sticking to something I already know.

I never thought about the speedboats bilgeboy, they would have a similar setup. The 2 I know up here were inbords without outdrives. still i'll have talk to the owners about the trojan.
BTW
it's not an easy decision to redo alot of the stuff. For a while i just wanted to preserve everything he'd done. But I'm so uncertain about alot of it, He was a real bush mechanic ;D
So when things have gone wrong i've had to first work out how he's made it, then figure away to fix em. I can't exactly read a book as it's original thinking. Hopefully by redoing alot of it i'll know where i'm at, and what needs maintaining more then others. I just need to be sure i'm not digging a big hole for myself.

saurian
27-12-2006, 11:35 AM
Crankit , big job.
I'm an outboard man , need I say no more.
If the the 307 and leg are faultless well I would'nt change a thing.
If they need money & time I'd be doing the sums.
Now copper and alloy don't mix so those things need to go.
Why do you need to change leg ratios ??
Did the old man put the prop on for a reason , ie; economy , thrust ???
I would'nt change everything staight up , the old boy had a reason
and I suppose thats what your trying to work out ???
Sorry I can't really help , I'm sure a few blokes have got more , lots more
sterndrive experience on this site than I .
They are probably on holidays.
Best luck , enjoy that boat don't stress over it.
Ta.

wayneoro
27-12-2006, 05:41 PM
mate these are a top classic boat to save your sanity toss the inboard you really have little choise there is a mag called 2nd hand boat secrets that covers your boat quite well ive got the 3rd edition pretty popular local ook shop will have one or get it for you cheers

Feral
27-12-2006, 06:27 PM
Mate an outboard to run that will cost a pretty penny, the old 307 is cheap to replace or to fix. I reckon you would be looking at over $10,000 for an outboard (new) big enough to run that beastie.

Also replacing a transom wont be cheap!

jimbo59
28-12-2006, 07:49 AM
Mate you say you only21 and know little and your've got heaps to learn,well can i give you some advice.

Don't throw money at the inboard because your going to reget it down the track,it's gunna gobble up money quicker than you can make it.

Even after you spend heaps on it it's gunna be a dog

Sell the chev it will pay for the pod,buy a used 2 stroke cheap(a150-175 will do the job)allow 5k for the outboard.

then just buy a steering kit and your off

wayneoro
28-12-2006, 08:05 AM
yer i can relate to that a friend on the gold coast had his motor and leg partly reconed for $10,000 3mths later another 5000 then tossed it out bought a 4 stroke out/b there are to many stories out there same as the boat is well worth doing right

wayneoro
28-12-2006, 08:11 AM
mate would you mind posting a pic the basket under the cover looks like a goos storage idea cheers

Kerry
28-12-2006, 09:49 AM
Yes an outboard conversion would be my preference. That 270 leg has quite some years on it and these things like the $$'s. Still a fair job to remodel that stern but at least you will only have to do it once.

Regards, Kerry.

FNQCairns
28-12-2006, 11:47 AM
Don't change a thing, just use it and enjoy, the money and time you will need to put into it is very large and what for! in the end?

If in 7 or 10 years some portion needs BIG money spent on it you can then go ahead.

Trust me a boat on the water -even if it will not conform to what is considered normal today is far superior to a boat in bit's or one that now conforms after big bucks but can do nothing more or very much better than before the rebuild.

Is it broke? if not there is nothing to fix, would your old man have taken this outlook? I suspect he respected function over form in that genuine old school way.

cheers fnq

Heno
28-12-2006, 12:19 PM
get to know how everything has been fitted and how it works,throw in the spares that may be needed and use it. "If it aint broke dont fix it"

blaze
28-12-2006, 02:41 PM
If one of the major problems is exhaust and engine noise, insulate the engine cover really well and lag the exhuast pipes with fibaglass.
cheers
blaze

seabug
28-12-2006, 04:33 PM
I have never had an inboard so not speaking from experience.

But IF you decide to keep the inboard do you really need the fan?
At high revs it uses a lot of HP and makes a lot of noise.

Your thoughts Kerry and others please?

Regards
Seabug

crankit
28-12-2006, 05:37 PM
Thanks for the replies. After all the advice I don't think i'll touch the transom for now, Maybe if i just cut that pod of and put an adjustible ouboard bracket for the spare motor and proper trim tabs, it will keep me happy for the short term. Will also have to keep an eye on those old holes that where covered up from previous exhaust setups! At least it keeps my options open later,

I have never had an inboard so not speaking from experience.

But IF you decide to keep the inboard do you really need the fan?
At high revs it uses a lot of HP and makes a lot of noise.

Your thoughts Kerry and others please?

Regards
Seabug


That fan is definitly going, i've been told if theres a fire it would fuel the flames,


For the engine i feel i got 2 options

A. Buy new manifolds and risers for the chev and try to make it last,

B.Use it as it is for the short term until those copper risers chuck it in, risking the chev, all the while saving for a new outboard

I'm not certain if i want an outboard yet, I have never been on an outboard powered boat this size so i woudn't know what there like, if there quieter, what there like to maintain, what there like for drive. So some research is in order and i'll have to sleep on it.

Posted by: wayneoro Posted on: Today at 08:11:10
mate would you mind posting a pic the basket under the cover looks like a goos storage idea cheers

Is this what your talking about wayeoro? Dad made these from security door screens he scored at an auction.

http://img206.imageshack.us/img206/6669/pict0010art5.jpg

http://img206.imageshack.us/img206/4104/pict0011akk6.jpg

I also went to the newsagent and angersonrobertson to buy "second hand boat secrets" they both said they don't have it and can't order it. Where bouts you get your's from? I've been hunting for info on dehavillands for ages.

crankit
28-12-2006, 11:24 PM
Ok I've been checking out the outboards.
:o I had no idea outboards were so expensive. Wouldn't I need atleast 200hp for comparable performance of the chev? New ones are over 20 gran + boat mods. And from looking at the forums a few people arn't buying them for keeps, they have em 3 to 5 years trade em in and buy new ones.

So a few questions regarding outboards

1.Has anyone here pulled one of the efi bigones this size apart, Can you replace the small internal bits when they wear.
Are they worth fixing when things go wrong?

2.Has anyone here got fuel consumtion figures on hand of a comparable size boat with outbords.

3.Do they last? - If i went for a new motor i'd want it to last as long as the volvo, nearly 30 years.

I guess seeing those posts about pricings on here and people who trade in outboards and boats so regurlarly for new ones has me worried. I can't see me ever selling this boat. And from what i've been told, the hull has years left to go, as old as it is.

jimbo59
29-12-2006, 08:54 AM
Hi crankit,people are funny they love keeping up with the jones so when fred bloggs next door gets a new motor they gets a new motor too.

The fan on the old chev is for getting rid of the fumes from petrol ect it is blowing them straigth out the engine box constantly because it wasn't designed to be in a boat.That's what happened here the other day a small leak and boom a whole family nearly lost there lives.

Some car nut will give you a grand for the old girl and you should be able to get the local ally bloke to knock you up a pod.

150_175 yamaha 8-10 years old will do the trick and be prepared to pay 3-5k.

Kerry
29-12-2006, 09:05 AM
150-175 is more than enough for these hulls. What sort of performance are you looking for?

Standard sort of power for these hulls when first made in the early 70's was the 130HP 4cyl Volvo, twin 60 outboards etc

As for the fan? No I wouldn't be happy with that setup, can't really see it doing a lot of good and quite dangerous when exposed. To be serious with inboard petrol engines then they really need a blower to properly exhaust any fumes as well as vapour detection.

Regards, Kerry.

crankit
29-12-2006, 07:36 PM
Posted by: Kerry Posted on: Today at 09:05:42
150-175 is more than enough for these hulls. What sort of performance are you looking for?

I'd be happy with a 25-30 knot cruising speed. The chev does bout 24 knots at 3300 rpm I've always felt like she was over reving cause there was plenty or power leftover, I don't like reving the old thing. But yeh id want 25-30 knots with power to spare if i went up the coast for a few days.

Thers 2 120 litre fuel tanks and a 100 litre water tank, these would all be filled on a few day trip up the coast, plus we;d usualy carry a fridge and a heap of other stuff, plus spares for the engine and a rubber boat on top. Also on average about 4 large people.

For 1 dayers on the reef, it be just one fuel tank full, maybe half of the water tank full, and sometimes up to 6, never less then 4 people.

Kerry
29-12-2006, 08:30 PM
Gee I'd be happy with 25-30 knot cruising speed as well but rather difficult on most days, big ask of a Trojan on anything else than good days.

That type of engine in a boat is not reknown for being fuel miserly, so might I ask how far "up the coast is" and how far does is go on a 120 litre tank?

Regards, Kerry.

crankit
29-12-2006, 10:05 PM
Posted by: Kerry Posted on: Today at 20:30:35
That type of engine in a boat is not reknown for being fuel miserly, so might I ask how far "up the coast is" and how far does is go on a 120 litre tank?

The highest up the coast we did was to lizard islans bout 6 years ago, I remeber stoping at cooktown for fuel, and I'm i'm pretty sure he aslo had a few 20 litre drums. Done many trips to hope island.

Out to the reef i'm pretty sure was bout 80 litres. so from Mossman FNQ bout 7am out to toungue reef, Cruising around to other spots take about 5 min not planing, this be every30 min to an hour. Be back at the ramp at around 5pm.
sorry i can't give ya a straight answer there.


Posted by: Kerry Posted on: Today at 20:30:35
Gee I'd be happy with 25-30 knot cruising speed as well but rather difficult on most days, big ask of a Trojan on anything else than good days.

You are right there kerry, it's a very hard riding old hull especially when not loaded up. i wouldn't dare do 30 knots in anything choppy. It was blowing about 10-15 knots when I last took it out and I just let it sit on the plane bout 21 knots, nothing more. I was being a bit optamistic with that last reply, but i'd want enough so it doesn't have to work hard when she's loaded.

FNQCairns
29-12-2006, 10:17 PM
Ring Dave's Boat yard in Cairns 07 4058 1335, they have a Trojan which had a new transom built a couple of years ago to run a single setback pod, forget what size engine is on it now 1990s Yam V6 I think but not sure. At least you will know what is up with performance/economy straight from the horses mouth.

The owner likes to chat at times and keep one hand on you wallet or he will try and sell you something.

cheers fnq

crankit
29-12-2006, 10:30 PM
Thanks FNQ, I'll give him a ring next time I'm in cairns. Be very interesting to see! Don't get to see many trojans around.