Few questions.Rib project - Page 3

paintman · 17 April 2015, 08:19

Wouldn't you be better going hydraulic steering if you're going to run 2 of them?
Plus no steering cable issues - mine's twin cables. The control cables aren't really an issue as they're much thinner & more manageable.

Nos4r2 · 17 April 2015, 10:11

Quote:

Originally Posted by A1an

I feel your pain, boating on a budget is a real struggle, especially when you have the size of hull you have.

IMHO?, a pair of those 130's are going to be shockingly pricey to run/maintain. I ran a pair of 60s on a 5.8m hull and fully loaded i was using anything up to 1.4 litres a mile. I couldn't stomach it.

I bought a four stroke and notched the transom to accept the single. Many people frown upon it, as long as its done properly I don't fully understand why. I've saved 40kgs on my transom so in theory it should sit a little higher in the water and the cut out takes the transom height to a normal long shaft transom anyway.

I've gone from 2 older/thirsty/pricey/inefficient 2 strokes to a modern/economical/lighter/more reliable 4 stroke. It's a win win situation in my eyes.

I don't have pocketfuls of cash I can chuck at a boat and couldn't be doing with the hassle of buying and selling. You can only piss with the cock you've got.

Basically what I'm trying to say is.....I'd cut the transom and go with a bigger single because I don't have the pockets but that's just me.

I suspect (but may well be wrong-Cobra would need to be asked) the transom wouldn't need to be cut for a bigger single- a 25" shaft would probably work.

Cost wise though, a second 135 at sub £2k, vs a second hand big new tech motor at £6k+, plus maybe another £1k for an auxiliary when you're probably splitting fuel costs 5 or 6 ways between divers is going take a long time to add up.

abyss · 17 April 2015, 11:36

Transom is 27 inch high.so even with xl shaft I have to notch it about 2 inches.that hull is really made for twins. I will look for second 135 mariner/mercury and give it a go. Up to then will work on the hull: make console , jockey seats etc.
I have hydraulic steering .

Nos4r2 · 17 April 2015, 12:30

Really, you may not have to notch it. Having the AV plate 2 inches above the keel isn't unheard of on some boats-particularly if you use a setback plate which you're obviously capable of making from earlier replies.

Essentially from memory, the further back the motor is from the transom, the higher it can be-though 7 inches isn't realistic. Do a search on here-the info is on an old post somewhere (probably by Cookee , Kitten or Dirk Diggler)

I'm not saying you HAVE to do it, just that you do have more potential options that just chucking another 135 on it.

A1an · 17 April 2015, 12:31

Quote:

Originally Posted by Nos4r2

Cost wise though, a second 135 at sub £2k, vs a second hand big new tech motor at £6k+, plus maybe another £1k for an auxiliary when you're probably splitting fuel costs 5 or 6 ways between divers is going take a long time to add up.

This is true. I suppose the reason it worked for me is I already had the two engines to sell, by the time I sold them I only needed another £1k for the newer engine and already had aux.

Horses for courses.

abyss · 17 April 2015, 16:08

Some shots of the engine transfer...
Of the Searay

abyss · 17 April 2015, 16:10

Lonely Searay 160

abyss · 17 April 2015, 16:13

Getting ready to work on the rib...

Nos4r2 · 17 April 2015, 16:20

As it's your 1st boating project, do you know about specifically using Sikaflex 291i or Purflex to seal the engine bolts to stop water getting into the transom? Silicone sealer isn't recommended at all as it doesn't last long.

abyss · 17 April 2015, 17:18

I know that you have to seal the bolts...didn't knew what sealer to use, thanks for that . Don't need to look for the answer when the time comes.
I'm not hanging the engine for good, just moking it up to see clearances ,lengths console and seat layout, etc, it would be a shame to buy second engine and find out after that they won't work because of some sh1t .

Pikey Dave · 17 April 2015, 18:48

Just bought some 291i from here, competitive price & next day service
http://www.uksealants.co.uk/sikaflex...0ml--p233.html

.....sh1t happens.......

Nos4r2 · 17 April 2015, 19:21

Cool

Try and do lots of Sikaflexing at the same time-it goes off quite fast in the tubes. OH, and once it's dried, it really doesn't come off. Clean it off anything you need to when it's wet, and wear 2 pairs of vinyl gloves while you use the sika. It's easier to pull a pair off and carry on than to keep stopping

It's very useful for bonding down consoles/seats etc as well-use decent 316 stainless screws to pull the console onto a bed of Sikaflex. That is, unless you want to glass them in.

If it's any help, my last rebuild thread is here:-

http://www.rib.net/forum/f8/ballisti...urb-48581.html

9D280 · 17 April 2015, 23:19

I've had a coupe of glasses of wine so I'm going to keep this high level

- the plate above transom "issue" may not be an issue if you have a raked transom... as the rake will park the Business end of the leg way outboard of the transom.

Did that make sense?

and can you get a pic of it looking along the bottom of the hull to give the "advice committee" a better feel for what your situation is?

abyss · 18 April 2015, 03:14

i have to get few glasses of wine to understand :who he's talking to?...
then few more to get an idea what he's saying ...
then after few last ones and some help from google :ah ...ok.
i will take some pics tomorrow ...but ,desicion is made:
-any one have a good running 135 merc/mariner?
i will also post in wanted section.

abyss · 19 April 2015, 15:52

is it worth:?
Mariner Mercury 135 PS ELPTO Aussenborder Ersatzteil Schlachtfest in Nordrhein-Westfalen - Brüggen | Gebrauchte Boote und Bootszubehör | eBay Kleinanzeigen
if i have to rebuild it...

Last Tango · 19 April 2015, 16:02

Quote:

Originally Posted by 9D280

I've had a coupe of glasses of wine so I'm going to keep this high level

- the plate above transom "issue" may not be an issue if you have a raked transom... as the rake will park the Business end of the leg way outboard of the transom.

Did that make sense?

and can you get a pic of it looking along the bottom of the hull to give the "advice committee" a better feel for what your situation is?

To give some the photo some perspective get a ruler or a length of wood held against the keel and projecting beyond the transom to the engine and lets see where it meets the gearbox....

9D280 · 20 April 2015, 01:30

Quote:

Originally Posted by abyss

i have to get few glasses of wine to understand :who he's talking to?...

don't worry. It's beer tonight so sense will prevail.

If you measure the height of the anti cavitation (ventilation) plate above the transom, the relative height of the two may be offset by the distance of the plate behind the transom as the water will rise as the hull passes the water in an Einsteinian relativity sort of way.

orrite ye huv a twin engine hull. It's set up fur twins. Ye neeeeed un autre moteur de 135 cheveux.

Normal service will resume shortly. ...

abyss · 20 April 2015, 02:56

you obviously enjoying it...?

9D280 · 20 April 2015, 19:44

Yip.

Ok nothing methanol based tonight so third time lucky....

Bottom line is how high relative to the bottom of the hull is your anti cavitation plate?

As you motor along the hull essentially creates a "hollow of air" behind it. The water previously under the hull rises to fill this gap and so the further back from the transom you get the further up it has got, so if your engine sits further back (either by trimming it up or use of a jack plate) the higher you can have the cav plate.

abyss · 20 April 2015, 20:34

Now we talking...
In another words even if my shaft is bit shorter then the transom at the mounting place I could compensate this by moving engine further back...makes sense. But I don't think you can compensate 7 inch.
Good to know for the future, but know I'm going twin and looking for twins or single to match.found one in Germany , have spoken to the seller he claims it was driven without oil for some time.3 cylinders have no compression. Would cost me 1225 delivered. Is it worth it?