dhutch
|
| posted on 22/11/12 at 01:03 PM |
|
|
Building a boat... what engine!
Im considering building a speedboat, plywood or strip plank construction, epoxy grp sheathed, trailable, with a 'fast displacment' type
hull shape and im afer suggestions for the engine.
Origanally half the point was to have a reason to own a rover v8, however as the project design progresses it looks as if that might be too heavy and
provide more power than I can use as the estimated required power is more like 50-75 horsepower. However I would still like something interesting and
petrol and wondered what people could come up with. One thought I had was a flat twin bike enigne but there all air cooled. Fiat twinair alsocame to
mind, but I expect it is still too new to be avilable economically. It will be fairly heavily silenced, but i would like it to make a nice noise when
its opened up and you do hear it.
Very much a pipedream at the moment, but I does no harm to think about these things!
Using this as my design lead for the boat itself.
http://www.nigelirens.com/ldl/yachts-product.php?id=7&idcat=1#
Daniel
[Edited on 22/11/2012 by dhutch]
|
|
|
|
|
JoelP
|
| posted on 22/11/12 at 01:08 PM |
|
|
simplest way by far is to just buy a second hand outboard and learn to service it yourself. I've had exactly the same dreams as you, and
realised that a stern drive is just expensive and and a ballache to connect up. Jet drive is inefficient. Inboard with a prop shaft doesnt work well
for speedboats. Sterndrive or outboard is the way forward, and of these, outboard is simplest.
Beware! Bourettes is binfectious.
|
|
|
blakep82
|
| posted on 22/11/12 at 01:10 PM |
|
|
V8 diesel would be my choice personally, on one very good reason
less risk of fire in the case of a fuel leak. limits choices and cheapness i know, but you don't want fire on a boat
________________________
IVA manual link http://www.businesslink.gov.uk/bdotg/action/detail?type=RESOURCES&itemId=1081997083
don't write OT on a new thread title, you're creating the topic, everything you write is very much ON topic!
|
|
|
MakeEverything
|
| posted on 22/11/12 at 01:15 PM |
|
|
quote:
Originally posted by blakep82
V8 diesel would be my choice personally, on one very good reason
less risk of fire in the case of a fuel leak. limits choices and cheapness i know, but you don't want fire on a boat
On the plus side, a fire on the deck of a boat is an international distress signal in itself!
I thought about this a few years back (but i dont live near the coast so jacked it in!) and i reckon i would have gone for a Ford V6. Cheap parts and
enough power etc.
As far as weight goes, surely you would just calculate the size of the boat to the maximum desired load using Archimedes laws etc? I would work out
the maximum weight that i would want to carry, which would specify the size of the hull for you.
Kindest Regards,
Richard.
...You can make it foolProof, but youll never make it Idiot Proof!...
|
|
|
Mr Whippy
|
| posted on 22/11/12 at 01:18 PM |
|
|
Well that is a beautiful boat but if that is your first one and especially using strip and plank I think you may be jumping in at the deep end big
time. One thing with homebuilt boats is the huge number that are started and not finished as people find out just how labour intensive they are, that
thing is a living nightmare unless you have built several simpler ones before. Even a plywood kayak takes ages to build!
I really suggest you start smaller and simpler, a small outboard hydroplane make from plywood for example to cut your teeth with. Another thing to
bear in mind is the price of marine timbers (Robbins Timber is one of the best) are just mind boggling as is epoxy resins paints etc
If you actually want to design one too, I'd recommend you build a large, scale construction R/C one to test the handling and construction
issues
Look before you leap
|
|
|
JoelP
|
| posted on 22/11/12 at 01:19 PM |
|
|
Id go from the other end - make it as big as you could trailer and store, then build it and work out a likely top design speed and pick an engine and
prop to match.
Beware! Bourettes is binfectious.
|
|
|
tegwin
|
| posted on 22/11/12 at 01:22 PM |
|
|
I would have thought a small lightweight turbo 4 pot would be a good idea... something around 1 litre? Some of the newer ones must be alloy
blocks?
Alternativley grab an old jet-sji (or two) and use the jet-drives and engines...
------------------------------------------------------------------------------------------------------------------------
Would the last person who leaves the country please switch off the lights and close the door!
www.verticalhorizonsmedia.tv
|
|
|
emwmarine
|
| posted on 22/11/12 at 01:34 PM |
|
|
At last something I can contribute too.
The boat design you are basing it is not a speed boat but looks to be a 'slipper type' design for river and lake use. As you say it is not
a planing hull but a displacement hull.
That design would only work on inland waterways.
Speed will be limited to the displacement limit which is proportionate to length and the hull shape is efficient until it gets close to that limit.
You do not need a lot of power to move a boat of that hull design which is why they sometimes fit electric power.
A slipper type design won't work with an outdrive it needs an underwater sterndrive. You will need to buy commercially available hardware,
including stern gland, prop, shaft and bearings, much of which is made of bronze and expensive.
In terms of horsepower, for a boat of the size shown in your link, for river use you would only need 20 hp max.
If you are thinking of building a speedboat in the more traditional sense, with a planning hull for coastal use then that would be a completely
different proposition. Home marinised car engines never work well, the outdrives cost as much as an outboard would have and wood is a crap material
for a planing hull sports boat.
Building a Dax Rush.
|
|
|
designer
|
| posted on 22/11/12 at 01:37 PM |
|
|
As said, nice looker, but the wrong hull.
|
|
|
AndyW
|
| posted on 22/11/12 at 01:41 PM |
|
|
2.5 mercury V6 with injection would be my choice, just like this little beauty in the clip, must watch to the end for high revs
link
[Edited on 22/11/12 by AndyW]
[Edited on 22/11/12 by AndyW]
|
|
|
Mr Whippy
|
| posted on 22/11/12 at 01:46 PM |
|
|
it actually gives the power required as that is an electric boat as 22kw or 30hp, only does 15knots so not really much of a speed boat
Maybe have a look at second hand speedboats, the small GPR ones tend to go for very little
|
|
|
emwmarine
|
| posted on 22/11/12 at 02:42 PM |
|
|
quote:
Originally posted by dhutch
Very much a pipedream at the moment, but I does no harm to think about these things!
Daniel
Sorry just read this bit.
Process needs t be similar to buying a car.
1) What do you want to use the boat for?
- coastal journeys ?
- water skiing ?
- off shore racing ?
- family days out ?
- fishing ?
The worst answer probably is:
- just fancied a boat to troll around in = lots of money into something that is used once.
2) Where will you use it?
- inland?
- coastal?
- offshore?
3) How big a boat?
- enough to overnight?
- day use?
etc.
You then have the issue that if you want to build a boat yourself you have probably as much difficulty in using it as the IVA test. I think for most
inland waterways they will want to see a BSS certificate and to use a boat in open waters it will need a CE mark and a hull number HIN etc etc - with
specific rules for kit boats. So much so that no-one really does it anymore.
If you want a 'speedboat' as others have said buy a few K you can get some great used boats. I would go for a Phantom 18 - with at least
150hp v6 outboard and budget for 5k to get a very good one.
Home built stuff around boats tends to be junk and go for junk money.
Apolloduck is your friend.
This is the first attempt at uploading a photo so here goes.
This is the only wooden boat I have owned. A Healey Ski-master, designed and made by the car maker Healey.
Very light marine ply and could plane with 40 hp but I broke it a few times as son as it got a bit rough. Sold it to a collector for a fair bit.
[Edited on 22/11/12 by emwmarine]
Building a Dax Rush.
|
|
|
minitici
|
| posted on 22/11/12 at 04:01 PM |
|
|
Put a couple of Lamborghini V12 marine engines in.
|
|
|
britishtrident
|
| posted on 22/11/12 at 04:39 PM |
|
|
This is the first attempt at uploading a photo so here goes.
This is the only wooden boat I have owned. A Healey Ski-master, designed and made by the car maker Healey.
Very light marine ply and could plane with 40 hp but I broke it a few times as son as it got a bit rough. Sold it to a collector for a fair bit.
[Edited on 22/11/12 by emwmarine]
Looks very identical to a late 1950s Pochin Craft 14 footer
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
|
|
|
emwmarine
|
| posted on 22/11/12 at 04:49 PM |
|
|
I think a lot of the late '50s and early '60s boats looked fairly similar with fairly flatfish bottoms and rounded chines. The
introduction of GRP by Shakespeare and Fletcher and the like allowed much better shapes to be produced and speedboats as we know them.
http://www.rmauctions.com/featurecars.cfm?SaleCode=mo09&CarID=r343&fc=0 you could buy a Healey car and matching Healey boat.
Building a Dax Rush.
|
|
|
dhutch
|
| posted on 22/11/12 at 05:17 PM |
|
|
What a lot of replies! Didnt know we had a load of boat people as well.
I have thread runing on another forum, which is prehaps a more comprehensive starting point. As said, the design specification is only just coming
together, and one of the things im most aware of is the need to design something that I have a use for once built, as well as to keep the build time
managable.
LINK: http://www.boatdesign.net/forums/boat-design/fast-displacment-hull-plywood-tunnels-hull-speed-45015.html#post595945
The main intended use is for occational summer weekend river use, either day use as, or primative 'camping' onboard wth a canvas cover.
Basicaly a 'kitcar of the water' if you like. As well as ot annual fortnights holiday in Salcombe.
Hence as said, it is not a highspeed planning hull, but a 'fast displacment hull' which is to put it simply a displacment hull the is
light and find enough to be able to acheive speeds above its hull speed, with I hope top speed of around 15-18 knots/mph.
I know several people who have built several boats, in plywood, cold moulding, and strip plank, so although I have never done it myself, have an idea
as to the amount of time it can take, even if still slightly naive as yet!
Daniel
|
|
|
jossey
|
| posted on 22/11/12 at 05:20 PM |
|
|
Have you seen that busa powered boat I also think they do an r1 and zzr engine too.
Thanks
David Johnson
Building my tiger avon slowly but surely.
|
|
|
minitici
|
| posted on 22/11/12 at 05:40 PM |
|
|
My all time favourite boat/engine combination would be an Albatross with the Coventry Climax engine.
|
|
|
MakeEverything
|
| posted on 22/11/12 at 06:06 PM |
|
|
quote:
Originally posted by minitici
My all time favourite boat/engine combination would be an Albatross with the Coventry Climax engine.
Want!
Kindest Regards,
Richard.
...You can make it foolProof, but youll never make it Idiot Proof!...
|
|
|
dhutch
|
| posted on 23/11/12 at 12:40 PM |
|
|
I have thought about buying an outboard and doing that, but it doesnt really fit with my expectations of what the baot will look like, and the fact
that I would like to soft mount and acoustically enclose the engine.
The plan would be to use 'conventional stern gear' rather than a retractable outdrive although im aware of the advantage of the latter in
terms of being able to beach the boat and simplify the trailer, and or, reduce trailed center of mass. But I need to look into costing up the options
obviously.
Suitable deisal is an option, although im not overly worried about having petrol on board having done a lot on small dingys and ribs which have all
been petrol. If you want safe fuel, our narrowboat is coal fired!
Key to getting the high speed displacment hull to work is keeping the weight down such that boat is light enough to overcome its hull speed while not
being a planning hull.
Ive used Robins before for building bits for the narrowboat and repairing sailing dingys, and as you say, the quality and service is second to none. I
ran out of one size having miss cut two lenghts and had to buy locally, side by side, while both where clearly douglas fir, the locally sourced suff
was that knotting and resinous it might has well have been budget pine!
I understand that legally the limit for trailer width is 2.55 metres and length 7 metres (circa 20ft) , but 2m overhang is allowed with a flag or
3.05m with in illuminated board, presumably ontop of the 7ms. bring the total to 10m or around 30ft, allowing for clearance to the towing vehicle.
The 'all electric' spec is indeed 30hp and 15knots, but there is a hybrid version which states 30mph with 120hp.
Daniel
|
|
|
Simon
|
| posted on 24/11/12 at 12:18 AM |
|
|
Engine from 306 diesel would be all you need. Looked (vaguely) into boat building a few years back - was hoping to use a couple of 2.7 jag/pug
diesels.
Decided didn't have a) time b) money c) space d) patience e) skill to start, let alone finish. Still have the plans though
ATB
Simon
|
|
|
coyoteboy
|
| posted on 24/11/12 at 01:13 AM |
|
|
Ours has a BMW I6 engine in it, it's basically the same as the cars 330 petrol engine, but with a big 4 barrel carb on top. Probably
doesn't suit the requirement though, not exactly frugal or light. Sounds lovely though. All of the marinisation is just a water cooled exhaust
manifold and heat exchanger.
[Edited on 24/11/12 by coyoteboy]
|
|
|
Dualist
|
| posted on 24/11/12 at 11:10 AM |
|
|
Don't muck about, get one of these 12 rotor engines....
http://www.rx7club.com/old-school-other-rotary-63/12-rotor-engine-94502
1/
Rotary build coming soon...
quote:
Originally posted by RichardK
I recently discovered that pigs can p i s s sideways when being transported 
|
|
|
plentywahalla
|
| posted on 24/11/12 at 11:21 AM |
|
|
Don't be put off by barrack room lawyers scaring you with tales of regulations. Waterways are not like roads and within limits you are free to
do what you like.
You are exempt from inland waterways (BSS) requirements if it is an open cockpit boat and not equipped with any cooking, heating or lighting
equipment. Also you are exempt from RCD (CE marking) if you build the boat yourself and do not sell it on for 5 years from the date of completion.
Go for it and good luck .... And why not stick to an electric motor??
Rules are for the guidance of wise men ... and the obedience of fools. (anon)
|
|
|
britishtrident
|
| posted on 24/11/12 at 01:10 PM |
|
|
Water Jet ?
water jet unit 
[Edited on 24/11/12 by britishtrident]
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
|
|
|
