bow thruster

kees · Veteran Member

bow thruster

chas · Senior Member

Single engines and tight marinas don't mix no matter how good you think you are.

Easy with twins, keep them on tickover and nudge in and out of forward and reverse gears but a single - no chance!

I see you chose the same model as I did

kees · Veteran Member

Hi Chas,
now I understand why it took you 5 winters to restore your Lochin, you painted her just as nice inside as outside. Nice job. I will need at least 5 winters before i am there.
I see you placed the bow thruster at exactly the same place as I did, but it looks the only logical place.
Tommy's hull looks the same as yours, but she don't has the reinforcement, is it original ? or also done in winter time.

here some pictures of the front side, and a few our harbourmaster made yesterday of Tommie's last fishing trip for this year. (fishing for cod at the edge of the fairway, just in front of the harbour)

best regards,
Kees.

chas · Senior Member

Hi Kees

---"Tommy's hull looks the same as yours, but she don't has the reinforcement, is it original ? or also done in winter time."---

Do you mean the additional cross beam? If so, I added that when I installed the thruster.

I wanted to emsure that my bow thruster tube was at least 1 diameter below the water line and at least 2 diameters long at the shortest point (the bottom) for optimum efficiency then, as far forward as I could get it for maximum leverage. This made the the 150mm dia tube of the Vetus Bow 55 preferable to the 185mm dia tube of the more powerful Bow 75 as I could mount it further forward and get better leverage. It also meant loosing less space inside.

Mine was built by Cresta Marine in (I believe) 1977. In certian light before I changed my windows you could still where "Cresta Sports Fisherman" had been written above the side windows.

Stugy's Lochin is very similar to mine with mant similar fittings and looks as if came out of the same yard at about the same time.

I don't know much about Lochin history but people talk about the "mark 2" version. These appear to have internal reinforcing ribs at about 450mm centres, spray deflector rails, and they appear to have removed the small strakes under the hull. The first photo shows "Salochin", (a boat I looked at in Lochins yard when I bought my spray deflector rails) and I know she has the reinforcing ribs, so she would appear to be a "mark 2"

I don't know but I doubt if they changed from "mark 1" to "mark 2" overnignt

I noticed from that superb shot of your c0ckpit that you have reinforcing ribs on your transom but do not appear to have transverse ribs on the sides. You also have spray deflector rails and appear to have the small strakes under the hull.

You also have the larger windows and the three small windows in the front cabin like I have (see second photo)

Cheers

Chas

-- Edited by chas on Sunday 22nd of November 2009 08:13:02 PM

Martin · Senior Member

Hi Chas/Kees

You have really given me something to think about with the bow thruster! It could be the answer to my problem. The pier I use for collecting passengers is exposed to strong tides at some times and being tidal means you cant always get on the side you want so the tide can push you off before you can get close enough to tie up safely.

I see you have both chosen the same model, obviously your thinking is similar and I wondered a) what made you choose this model and b) what model is it?

I have already asked the yard for a quote for fitting so I should have some idea soon. It will mean that one or more other of my winter projects will have to be put on hold for a bit but as always, running elderly boats is a compromise.

Kees, you were lucky you found the badly repaired hole in your hull, I hope there aren't any more.

Regards to all

Martin

chas · Senior Member

Hi Martin

Nice to see some activity on the forum after another long period of very quiet.

Mine is a Vetus BOW 55. See previous posting for why I chose it.

Our marina is very tight and it turned my boat from an "unmanoeverable pig" into "no problem"

If you want any more help, let me know.

Cheers

Chas

kees · Veteran Member

Martin,
you can find a bow thruster calculation in the vetus catalog, but it uses wind force as reference. I used this calculations to place a bow thruster in our last boat (as it was a toy in 6 kn current) only to find that 6 kn current is twice as strong as wind fore 6.

regards,
Kees.

chas · Senior Member

Hi Gents

No bow thruster is going to overcome a 6kt current - that's flat out displacement speed for a 25' boat, going forward with about a 50hp engine driving it.

The data in the Vetus catalogue does direct you towards a BOW 55 for a 10 metre boat with either a BOW 60 or possibly a BOW 75 as alternatives.

However the larger tube diameter of the BOW 60 negates the slight increase in thrust as (as I said before) the tube would have to be mounted further back thus loosing leverage.

I did consider a BOW 75 but you can only run that one for two minutes continuous as opposed to four minutes for a BOW 55. Also there's the positioning of the larger diameter tube.

So far, I had no reason to regret the selection.

Cheers

Chas

Martin · Senior Member

Hi Chas

Thanks for the information. I have never even looked into bow thrusters before so hearing from someone who has done all the calculations and fitted one that they are happy with is by far the best way for me to make a decision. I looked on the Vetus site today and they are about £1200. What extra bits do you need ? I see there are tubes and controls galore, do these units come as a kit or do you have to buy everything separately? My fuse box and distribution board are on the back of the dash stbd side so no long wires to worry about with voltage drop etc. Do you have the 24v or 12v version? LJ is 24v and has 2 banks of batteries which can be switched 1 2 or both. I see that a seperate bank is advised but fitting another bank is not what I would like to do as I don't want to increase the bow weight anymore if I can help it. What do you decide to do?

Are you still on the water? LJ was haualed out last Tuesday and now sits at Mc Sweeneys yard Balvicar Isle of Seil and will be there till the end of march. I am planning on taking out the engine and doing some cleaning/painting of the engine and bilges. In the meantime I am doing a bit of work on another charter boat doing some survey work off the Isle of Tiree. Check out Elizabeth G charters, she is an ex Norwegian safety vessel and very well kitted out for extended cruises, a real little ship.

Cheers and thanks again

Martin

chas · Senior Member

Hi Martin

Sorry mate but I did write a full reply and try to upload some photos but there is one photo which screwed it up (I think it is a Bitmap and doesn't seem to work, just jammed everything up)

I'm a bit knackered now but I'll rewrite it and re post.

What youv'e been told about separate batteries in the bows is a cr@p way of doing it. I've taken mine from the main starter bank and it's fine.

I'll post your shopping list tomorrow.

Cheers

Chas

kees · Veteran Member

Hi Martin,
just see that fox's gives 25 % dicount on Vetus bow thrusters.
but this is installed and maybe they are on the other side of England for you.

best regards,

kees.

chas · Senior Member

Hi Martin

Here we go again.

Buy a 24 volt thruster as it is half the current draw of 12 volts and you do not need a separate battery bank.

In addition to the thruster, you will need the following:

1. The tube. (I'm pretty sure that I bought the 600mm long one)

2. Control head. (I bought the BPSE2 which has two push switches but I now think that the BPJE2 which has a little "joy stick" type switch would have been better.)

3. Control cable. (The 6.0 metre one was long enough for my boat.)

4. Power cables - round about 50mm square conductor size. (If you tell me the "round trip" legnth, I can size them for you.)

5. Crimps for the above and shrink tube. (You will need a big crimping tool for this but you may be able to borrow one.)

6. 125 Amp slow blow fuse.

7. Fuse holder for the above.

Take the power supply from your engine start batteries as close to the battery switches as possible.

Don't buy it now - the boat show is on next month and people will be offering "deals"

If you have anymore questions, don't hesitate to ask.

Mine's still in the water, I will have it out for a couple of weeks in March for re-antifouling and anode changes etc then be ready to go for April (touch wood)

Cheers

Chas

Martin · Senior Member

Hi Kees

Thanks for the info. I got an e mail from Boats and Outboards with the offer so I have phoned them to see if they will give me the same discount for supply only. You are right Fox's yard will be much closer to you than it is to me. I'm guessing that it will be 600 miles from me and almost 800 by sea if I go through the Caledonia canal !

Chas's idea is probably best, if I wait fro the boat show I will get a good deal then.

Regards

Martin

Martin · Senior Member

Hi Chas

Thanks for the info. I can price the bits up now and get a rough idea of cost but I am sure your right about the boat show offers. Fox's are offering 25% off for supply and fit at the mo but they are light years away from me.

Considering going to the boat show it is years since I have been and things have moved on so much I need to get up to speed again with what is on offer.

I'll keep you posted on progress but I am more and more thinking that a bow thruster would change my life for the better.

Kind regards

Martin